Browse Topic: Finite element analysis

Items (4,181)

Application of Machine Learning for the Prediction of Automotive Panel Oil Canning to Accelerate Design Exploration

2026-28-0187

To be published on 11/05/2026

Oil canning, characterized by localized buckling and surface waviness in thin metal panels, is a critical quality parameter in the automotive industry. Since outer panels serve both structural and aesthetic functions, even minor surface distortions can adversely affect perceived vehicle quality. Traditionally, evaluation of oil canning relies on extensive nonlinear Finite Element simulations. For example, assessing a single hood design variant may requires thousands of nonlinear Finite Element analyses. Considering multiple design iterations across major vehicle panels including hood, roof, doors, fenders, and trunk, the total number of simulations can exceed tens of thousands, leading to substantial computational cost and development time. Consequently, this conventional approach is both time intensive and resource demanding. To address these limitations, advanced Machine Learning techniques are employed to significantly reduce simulation effort as well as accelerate design exploration. Initially, a deep learning based one-dimensional Reduced Order Model is developed to predict load–displacement response and oil canning propensity for a given panel. Indentation points on the hood panel are selected using a space filling Latin Hypercube sampling method. The Machine Learning based one-dimensional Reduced Order Model is trained by using 300-500 indentation points and validated using approximately 40-50 unseen indentation points. The verification is performed on multiple hood geometries. The predicted results demonstrate strong correlation with Finite Element generated load–displacement curves with that of ML based 1-dimensional reduced order model. Furthermore, to enable rapid design exploration across different panel geometries, a dataset of 40 different hood designs is utilized. A geometric deep learning approach is applied to cluster panel geometries, and the resulting representations are used within a 3-dimensional deep neural network tool Ansys SimAI™ to predict oil canning propensity and quantify it using the canning ratio. Validation study is carried out on unseen panel geometries, and the Machine Learning predicted oil canning zones show good agreement with Finite Element identified critical regions. The proposed Machine Learning framework reduces prediction time from hours to minutes, offering a scalable and cost-effective solution for early-stage design evaluation and mitigation of oil canning in automotive panels.

Sarnobat, Rajvardhan Vilasrao, Kumar, Dinesh, Jawale, Akshay, Balaji, Ananya, Kulkarni, Shreya

Influence of Transversely-Isotropic Lining Elastic Constants on Brake Squeal in S-Cam Drum Brakes: An Optimization Framework

2026-28-0161

To be published on 11/05/2026

Brake squeal in heavy-duty S-cam drum brakes remains a persistent NVH challenge, primarily driven by friction-induced modal instabilities. Existing studies on drum brake squeal mitigation largely emphasize geometric modifications, stiffness tuning, or the application of damping treatments, while the influence of directional stiffness characteristics of friction linings remains insufficiently explored. This research presents a novel, material-centric approach by modelling the brake lining as a transversely isotropic material, characterized by six independent elastic constants, and systematically quantifying their influence on squeal-prone unstable modes using Complex Eigenvalue Analysis (CEA). A validated finite-element model of a production S-cam drum brake assembly is developed and correlated through experimental modal analysis, ensuring close agreement between predicted and measured natural frequencies and mode shapes. The validated model is then integrated with a Design of Experiments (DOE) within commercially available FEA software to quantify both main effects and higher-order interactions across practical ranges of in-plane and out-of-plane elastic moduli and shear constants. To enhance the predictive accuracy of the surrogate models, a subsequent sampling–fit study is conducted, significantly improving the coefficient of determination (R2) of the response surfaces. The refined surrogate models are employed within a Global Response Surface Methodology (GRSM) framework to perform multi-parameter optimization aimed at minimizing squeal propensity under representative operating conditions. Finally, complex eigenvalue analysis quantifies the impact of the optimized transversely isotropic property combinations on modal stability, establishing a predictive, optimization-driven methodology for robust, noise-free drum brake design. The study culminates in the identification of an optimized transversely isotropic elastic-constants signature for the friction lining, providing actionable targets for friction material formulation and reinforcement alignment. Unlike prior research focused on isotropic material assumptions or component-level design changes, this first-of-its-kind methodology advances the state of the art by enabling friction material– centric NVH optimization for heavy-duty drum brake systems.

Philip, Rony, Muralidharan, Sudharsan, Mohanam, Gopalakrishnan

Enhancing FEA Preprocessing Efficiency through a Multi AI Model Strategy

2026-28-0174

To be published on 11/05/2026

Finite Element Analysis (FEA) plays a vital role in accelerating product development and reducing overall engineering costs. Accurate simulation of powertrain components requires extensive preprocessing of solid models. Detailed contact definitions and bolt representations are required to properly evaluate screw joints. Pipe joints present similar challenges, as they often incorporate various types of nuts and connectors. As a result, engineers spend a significant amount of time manually modelling these joints. Automating the modelling process is difficult due to the high variability in bolt sizes and pipe joint designs. This paper proposes AI-based models to automatically classify these components and extract their distinctive geometric features. Because bolts and pipe joints have wide feature variations, developing a generalized AI model requires a large dataset which is often hard to obtain. To address this limitation, this paper explores strategies for generating smaller, specialized AI models tailored to each unique joint type. This study describes the development of deep learning neural network models capable of learning distinguishing features of different joint configurations from limited training data. A multilayer graphical neural network architecture is employed, enabling efficient extraction and representation of these unique geometric characteristics. The proposed models can robustly generalize different joint types while maintaining high classification accuracy and reliable feature detection despite constrained training data availability. Automated workflows have been implemented in commercially available preprocessing tools to validate the proposed AI methodology and demonstrate its effectiveness in practical engineering applications. The integration of AI model automation in preprocessing tools significantly reduces engineering effort and repetitive manual preprocessing steps. This work highlights the potential of hybrid AI models to accelerate CAE workflows and provides scalable framework for future automation in FEA.

Jayachandran, Janarthanan, Agarwal, Deepak

Thickness Optimization of Constrained Layer Damping Shims for Reducing Friction-Induced Instabilities in Drum Brakes

2026-28-0160

To be published on 11/05/2026

Commercial vehicles predominantly employ drum brakes because of their low cost, robustness, and simple construction. However, with the increasing push toward quieter powertrains, particularly in electric commercial vehicles, brake squeal has become a dominant noise source. The inherent complex and chaotic nature of brake squeal makes its prediction and suppression especially challenging. Traditional squeal mitigation strategies, such as modifying component mass and stiffness or using materials with higher native damping (e.g., cast iron), are inherently constrained in their capacity to mitigate instability. In such scenarios, constrained layer damping (CLD) shims have proven to be an additional, effective and practical solution in disc brakes, which is motivating growing interest in extending similar concepts to drum brake applications. A key challenge in adopting shims for drum brakes lies in identifying and achieving the required damping level necessary to suppress squeal while adhering to stringent packaging, manufacturability, and cost constraints of foundation brakes. Establishing a clear relationship between squeal propensity, noise intensity, and target damping is therefore essential. While past CLD studies discuss layer-thickness effects in generic structures and caliper brakes, no work applies thickness optimization to brake shims in a drum brake assembly. This paper presents a systematic and target-driven framework for the design of CLD shims for drum brake applications. The approach initially defines the damping requirement for squeal suppression using system noise metrics and dynamic stability evaluations. Based on this requirement, a design optimization approach is employed to determine the appropriate thickness distribution of the individual shim layers, while accounting for practical constraints such as packaging limitations, material feasibility, and manufacturing considerations inherent to foundation brake systems. The optimized CLD shim configurations obtained through this process are subsequently integrated into the drum brake assembly and evaluated using complex eigenvalue analysis. The simulations utilized a validated FE model of the S-cam drum brake assembly, whose accuracy was established through experimental modal analysis–based correlation. The results indicate that the proposed target-based shim design methodology leads to a measurable improvement in modal damping and system stability, thereby demonstrating its effectiveness as a practical and robust approach for brake squeal mitigation in drum brake systems.

Muralidharan, Sudharsan, Philip, Rony, Mohanam, Gopalakrishnan

Efficient Finite Element Modeling and Sensitivity Analysis of Adhesive Joints for Early-Stage Battery Pack Design

2026-28-0190

To be published on 11/05/2026

The increasing adoption of structural adhesives in electric vehicle battery packs introduces challenges in predicting joint performance under complex loading and operating conditions. While advanced material models can capture detailed failure mechanisms, their application in early-stage design is often limited by extensive material characterization requirements and high computational cost and time. This study presents a computationally efficient finite element methodology for screening-level assessment of adhesive joint stress distribution and utilization using readily available material data from standard datasheets. The approach is specifically developed for early design stages, where rapid assessment, limited input data, and multiple design iterations are critical. The method is compared against adhesive manufacturer material datasheet strengths using strength-normalized loading to assess consistency of load transfer representation, hotspot locations, and relative stress-utilization trends. It is further extended to evaluate multiple joint configurations, including lap joints, T-joints, and hybrid joints, enabling a broader assessment of adhesive behavior across different loading conditions. A systematic design sensitivity analysis is performed to investigate the influence of key parameters such as adhesive bonding area, and geometric variations on joint stress utilization and hotspot sensitivity. The results highlight the capability of the approach to identify key design sensitivity parameters within the studied joint configurations and support informed decision-making during the concept development phase. The study demonstrates that the proposed methodology enables efficient screening of design concepts, can reduce reliance on high-fidelity material models during early-stage concept screening, and supports reduced evaluation turnaround time. This work establishes a practical right-level modeling strategy that complements advanced simulation techniques by enabling faster iterations, reduced computational effort, and compatibility with existing automotive CAE workflows.

Sugumar, Mohanraj, Bhat, Sadashiv

A Surrogate Modeling Approach for the Weight Optimization of a Two Wheeler Chassis with PSD Based Durability Validation

2026-28-0207

To be published on 11/05/2026

As the global automotive industry pivots toward sustainable mobility, reducing vehicle curb weight remains a paramount objective for enhancing energy efficiency and range. This paper presents a robust and comprehensive methodology for the light weighting of a two-wheeler chassis through the integration of Design of Experiments based optimization and Power Spectral Density durability analysis. The study begins by establishing a baseline durability profile for the vehicle using frequency-domain durability simulations under random vibrational loading, ensuring a benchmark for structural integrity. To explore the design space effectively, frame tube thicknesses are parameterized, and a Design of Experiments design matrix is constructed using Modified Extensible Lattice Sequence technique. This design matrix is solved, and a response matrix is built. These two matrices are combined, and appropriate curve-fitting techniques are applied to construct a Reduced Order Model. This mathematical surrogate model enables the rapid evaluation of the frame’s response under varying frame thickness combinations, thereby avoiding computationally expensive traditional Finite Element Analysis iterations. The optimum combination of frame tube thicknesses is identified using the Global Response Surface Method. This configuration minimizes the overall mass of the vehicle while strictly maintaining predefined durability and safety targets. The final optimized frame is evaluated by a secondary Power Spectral Density durability analysis to validate the accuracy of the surrogate model’s predictions. The integration of this metamodel-based design approach results in a significant reduction in structural weight. Ultimately, this framework accelerates the design cycle by developing a lightweight, cost-effective, and durable structure, thereby minimizing the overall time-to-market for sustainable automotive products.

Chettiar, Alfred Selvamani, V., Vinothkumar, S., Deepak, Praveen, Kannan

A Physics Artificial Intelligence Framework for Durability Analysis of Motorcycle Brake Pedal

2026-28-0188

To be published on 11/05/2026

The brake pedal assembly is a critical load bearing automotive component that must perform reliably under severe service conditions, especially during emergency braking events. Structural assessment is commonly carried out using computationally intensive non-linear finite element analysis, which can limit rapid design iterations during early product development. This study presents a physics informed surrogate modelling framework for predicting displacement and von Mises stress responses of a brake pedal directly from unstructured three dimensional mesh geometry. A structured dataset was created through parametric morphing and a Design of Experiments approach by varying pedal arm angle, pedal moment length, flange/web thickness, and combined geometric conditions. The simulation database was developed using conventional solvers and the generated cases were used to train Physics Artificial Intelligence based on the Transformer Neural Simulator architecture. The trained model showed close agreement with conventional solver results for both peak response values and contour distributions. For representative testing cases, predicted displacement and stress responses remained within acceptable engineering tolerance compared with the finite element baseline. After training, the PhysicsAI workflow reduced the prediction turnaround time compared with the conventional solver workflow. The results suggest that Design of Experiments driven datasets combined with geometric deep learning can provide an efficient workflow for rapid brake pedal structural assessment during concept development and iterative design studies.

N., Rengarajan, Praveen, Kannan, Philip Thomas, Febin

Rapid Optimization of Body Structures Using an Interface Simplified Super-Element Model

2026-28-0183

To be published on 11/05/2026

Finite element (FE) models of Body In White (BIW) structures are inherently large and computationally intensive due to a high number of degrees of freedom. Performing optimization studies of body structures in a full BIW model requires a significant amount of time, as each optimization cycle requires multiple iterations of the complete FE model. To reduce computational effort, techniques such as the Component Mode Synthesis (CMS) based reduction methods are commonly utilized. In this work, we adopt the Craig Bampton Nodal (CBN) approach by retaining the component targeted for optimization as the residual structure, while condensing the remaining BIW into a super element. This strategy significantly decreases simulation runtime. To generate the reduced model, all the interface nodes that connect the retained residual with the super-element structure need to be defined as analysis sets (ASETs). Earlier studies primarily considered residual structures connected through simple RBE2 bolt connections, resulting in a relatively small set of ASET nodes. In the present work, we address more realistic BIW assemblies incorporating complex joining technologies such as spot welds, structural adhesives, bolts, rivets and other intricate connection schemes. This leads to a substantially larger number of ASET nodes. A high ASET count increases boundary condition complexity, memory requirements, and overall simulation runtime, thereby limiting the efficiency of the reduced model. This paper proposes a novel methodology to simplify the connection interfaces between the optimization component and the rest of the BIW while preserving essential dynamic characteristics. With this strategy the number of ASET grids is reduced by roughly 70%, thereby reducing the computation time by approximately 80% without compromising accuracy. The resulting reduced order model enables rapid execution of multiple optimization studies through an efficient use of computational resources, thereby reducing overall lead time and improving the feasibility of iterative design exploration in early vehicle development.

Rajendran, Hariprasad, Pal, Arkaprabho, Schauwecker, Florian

Integrated Virtual and Field Assessment of Stabilizer Bar for Truck Rollover Stability and Strain-Force Calibration

2026-28-0168

To be published on 11/05/2026

Rollover stability is a critical safety requirement for heavy-duty trucks, particularly during severe manoeuvres and tipping-prone operating conditions. Accurate estimation of stabilizer bar forces plays an important role in assessing vehicle rollover behaviour. This study presents a finite element-based virtual strain gauge calibration methodology for estimating stabilizer bar forces from measured strain signals, using a heavy-duty vehicle tipping stability application as an industrial case study. A high-fidelity vehicle dynamics model was developed to assess the influence of the stabilizer bar on vehicle roll performance. To increase confidence in the virtual assessment, strain measurements were obtained from instrumented stabilizer bars during durability track testing and correlated with simulation results. A key challenge in the measurement process was the calibration required to convert strain signals into applied forces. To address this, a virtual calibration approach was developed using finite element analysis to establish linear strain-force transfer relationships. By combining FEM-derived transfer functions with measured strain data, stabilizer bar forces were successfully reconstructed under real operating conditions without the need for conventional physical calibration. Correlation between simulation and test measurements demonstrated the capability of the proposed methodology to estimate component loads with good accuracy. The results show that virtual strain gauge calibration can significantly reduce reliance on dedicated test rigs and prototype-based calibration activities, enabling earlier load assessment and more efficient chassis development. The methodology is scalable and can be extended to other dynamically loaded suspension and chassis components for durability and vehicle dynamics applications.

Thirunavukkarasu, Siddeshwaran, Sheepri, Sunil, N., Balagangadharan

A Sequential Structural Optimization Framework for Chassis Components Using Efficient Linearized Finite Element Models

2026-28-0200

To be published on 11/05/2026

As the global automotive industry increasingly prioritizes electrification and long-term sustainability, the demand for aggressive lightweighting in automotive chassis engineering has intensified. This study presents a process-driven, multi-stage structural optimization workflow designed to maximize total mass reduction while maintaining rigorous structural performance. To mitigate the high computational costs and software license overhead of nonlinear Finite Element (FE) analysis, the methodology transforms complex models into efficient linear representations. This strategic shift preserves critical structural behaviors while significantly enhancing license efficiency and total computational simulation throughput. The novelty of this workflow lies in an integrated optimization loop that begins with Topology Optimization to define primary load paths, followed by Free Shape Optimization to mitigate stress concentrations. By embedding manufacturing constraints such as draft angles and minimum thickness directly into the optimization process, the methodology effectively eliminates traditional redesign cycles. Optimized designs are then seamlessly translated into CAD via advanced ANSA tools for validation of von Mises stress, plastic strain, and buckling. This synchronized transition from analysis to realization reduced the development cycle by 50%, enabling a design freeze significantly faster than conventional methods. The integrated approach achieved a 15% mass reduction while meeting all functional durability and crash requirements. Given that a 1% reduction in mass correlates directly to a 1% reduction in CO2 emissions, the resulting design substantially minimizes the vehicle's total carbon footprint. By lowering material consumption and maximizing computational efficiency, this study offers a repeatable solution for balancing simulation fidelity with the urgent demands of modern sustainable automotive design.

Venkataraman, Nageswaran, Rajendran, Hariprasad, Karimbedu, Saikumar, Yadav, Balwan

Investigation on Dynamic Expansion Response and Structural Safety Assessment of Typical Polygonal Fabric Gasbags

2026-99-2337

10/30/2026

The geometric structure of a gas bag has a profound effect on its effectiveness in transferring energy and reliability of its structure when rapidly expanding. Even though there have been considerable improvements in high-performance composite materials such as Kevlar, the transient dynamic reaction and possible rupture mechanisms associated with particular polygon shapes have been greatly unexplored. In this paper, we focus on conventional polygonal gas bags, and perform extensive inflation tests using high-accuracy transient data recorders to monitor the development of the dynamic pressure. In order to overcome the limitations of physical testing, a highly non-linear dynamic finite element model - based upon the application of the *MAT_FABRIC material model in LS-DYNA - is used. This technique allows the systematic examination of how changes in geometric parameters affect the performance of payload dispersion and membrane stress distribution. The results indicate unique ways of deploying depending on their geometry. The circular gas bags are capable of obtaining a velocity of the payload of 4.23 m/s but have high stress concentrations of up to 426 MPa due to the lack of geometric boundaries which make them prone to tearing failure. Rectangular gas bags with very large aspect ratios will experience a tubular expansion deformation that causes energy transfer efficiency to plummet; the release speed of these types of gas bags falls below 2.77 m/s. Ultimately, the optimal structural design is a regular hexagonal shape that optimally balances work performance and structural safety. It can keep good levels of energy transfer efficiency with a final release velocity of 4.12 m/s. Moreover, it successfully stops the continuous hoop tension and reduces the peak stress by around 46 percent through straight edge boundary constraints. This complete research offers an adequate scientific foundation to the anti-burst design of sophisticated polygonal gas bags.

Wang, Jinwei, Shi, Lv, Hou, Jingjing, Li, Yilong, Li, Dailin, Liu, Zhiyi

Research on Dynamic Response and Impact Resistance of Airport Pavement Made of Gradient Carbon Fiber Reinforced Composites

2026-99-2346

10/30/2026

Aiming at the engineering problems of easy cracking and insufficient impact resistance of traditional airport concrete pavement under complex dynamic loads, this paper studies the application of functionally graded carbon fiber reinforced polymer ( FG-CFRP) in airport pavement. Based on the modified Halpin-Tsai model and the first-order shear deformation theory, the dynamic finite element control equation is established. Based on the COMSOL Multiphysics platform, the modal characteristics and transient impact response analysis are carried out, and the dynamic response of the aircraft under moving wheel load is simulated. The static bending test of FG- CFRP plate samples made in the laboratory was carried out, and the numerical model was calibrated. The relative error of test-simulation was controlled within 5 %, which verified the accuracy of predicting static response. The carbon fiber volume fraction gradient curve was parametrically studied to reveal the sensitivity of the gradient to impact and stress reduction. The key engineering factors such as long-term environmental durability and life cycle cost of FG-CFRP pavement are discussed, and targeted improvement and optimization strategies are proposed. The results show that the fundamental frequency of the gradient plate is about 1.93 % lower than that of the homogeneous plate, and the vibration mode characteristics are highly consistent. The peak displacement of transient impact is reduced by 9.4 %. Under the action of moving wheel load, the peak Von Mises stress decreased from 5.32 MPa to 2.15 MPa, with a decrease of 60 %. The gradient design realizes efficient load diffusion and impact hardening through the surface high modulus layer, and the gradual change of interlayer wave impedance promotes the dissipation of stress wave, which significantly improves the safety reserve and dynamic stability of pavement structure. This study verifies the application feasibility of FG-CFRP in high-performance airport pavement engineering, and provides innovative material solutions and theoretical support for the development of a new generation of long-life and high-reliability airport pavement.

Li, Zhenyue

Study on Fatigue Crack Growth of Sandwich Composite Panels with Opening

2026-99-2327

10/30/2026

Owing to their remarkable specific strength and stiffness, coupled with superior impact resistance and thermal/acoustic insulation, sandwich composite panels are extensively utilized in marine, aerospace, and transportation sectors. In contrast to conventional monolithic structures, the multi-layered architecture of sandwich panels introduces complex fatigue failure mechanisms that are not yet fully understood. This study experimentally investigates a U-shaped core sandwich panel featuring a rectangular hatch opening under uniaxial tensile fatigue loading, aiming to characterize its crack initiation and propagation behavior. Subsequently, a custom three- dimensional fatigue crack growth simulation code is developed, grounded in linear elastic fracture mechanics and the extended finite element method (XFEM). A comparison with experimental measurements reveals that the maximum relative error between the predicted and observed fatigue life is 15.7%. The findings offer a theoretical foundation and a technical reference for the fatigue design and life assessment of such sandwich structures.

Chen, Siyu, Xu, Yunze, Liu, Gang

High-Temperature Sealed Disc Spring Compression Load-Holding Performance Testing and Material Parameter Calibration

2026-99-2322

10/30/2026

In high-temperature sealed assemblies, disc springs provide sustained preload to suppress leakage. However, at elevated temperatures, material creep and stress relaxation may reduce elastic recovery and accumulate permanent deformation, thereby degrading sealing reliability. Because the material properties of commercially procured disc springs vary with suppliers and production batches, they are difficult to apply directly in the analysis of high-temperature components. This study investigates Inconel-800 disc springs. Sustained compression tests were conducted at 600–900 °C to systematically obtain load–time responses and the temperature dependence of permanent deformation. The results show that, as temperature increases, the rate of force decay accelerates significantly and the residual load decreases markedly. At 800 °C and 900 °C, the permanent deformation approaches the compression limit, indicating that time-dependent material deformation becomes the dominant factor. Based on these results, a finite-element model consistent with the test conditions was established. Material creep parameters were calibrated from component-level compression data by minimizing the discrepancy between simulated and experimental curves. The identified parameters were validated under different temperature conditions and loading cases. The simulation results agree well overall with the experiments, and the errors remain within engineeringly acceptable limits. This study provides baseline data and an engineering method for obtaining material parameters to support material selection and structural optimization of high-temperature sealed disc springs.

Yang, Yuyao, Cai, Xianhui

Multiscale MD-FEA Investigation on Large-Deformation Mechanical Behaviors of Hydrogels Modified with Ionic Liquids

2026-99-2306

10/30/2026

Hydrogels incorporated with ionic liquids (ILs) demonstrate broad application prospects in the fields of wearable flexible sensors and human physiological monitoring. Nevertheless, the intrinsic correlation between microscale intermolecular interactions and macroscale nonlinear mechanical responses under large tensile deformation has not yet been fully clarified. In this work, a coupled numerical framework integrating molecular dynamics (MD) and finite element method (FEM) was adopted to explore the mechanical behaviors of poly(acrylic acid)/N,N’-bis(acryloyl)cystamine/ionic liquid (PAA/NB/IL) hydrogels under large deformation. A series of molecular models with graded IL doping levels were established to characterize the structural rearrangement and energy change characteristics during uniaxial tension. Numerical results from MD simulations reveal that the addition of ILs strengthens non-covalent interactions such as van der Waals forces and electrostatic attractions, and further drives covalent bond stretching and angular deformation to bear external loads under high-strain conditions. Meanwhile, a generalized Maxwell constitutive model, whose Prony-series parameters were fitted by experimental stress-relaxation data, was introduced into FEM numerical calculations. The simulated quasi-static tensile properties are highly consistent with experimental measurements. Comprehensive analysis demonstrates that the mechanical enhancement induced by ILs stems from the synergistic effect of covalent structural deformation and the reconstruction of non-covalent interactions, which offers valuable theoretical guidance for the development of hydrogel materials applied in large-deformation engineering scenarios.

Li, Sitan

Pressure-Type Anchors in Weathered Rock for Transportation Infrastructure

2026-99-2366

10/30/2026

In transportation infrastructure constructed in mountainous and rocky regions, such as highway slopes, railway cuttings, bridge abutments, and tunnel portal slopes, uplift-resistant anchorage systems are widely required to ensure structural stability and service safety. To support anchorage design in such conditions, this study investigates the uplift bearing behavior, load-transfer mechanism, and key design parameters of pressure-type rock anchors in weathered rock strata through a combined field-and-numerical approach. A rock anchorage project in mountainous terrain in Shaoxing, Zhejiang Province, China, was adopted as the prototype case, and two representative anchors installed in strongly weathered and moderately weathered tuffaceous sandstone were selected for field pullout testing and three- dimensional finite element simulation. The failure characteristics, uplift load–displacement response, axial strain distribution of the grout body, and the effects of anchorage length and rock-socketed length were systematically examined. The results show that pressure- type rock anchors exhibit favorable uplift resistance in weathered rock strata. No overall pullout failure occurred during the tests, and no obvious cracking or significant ground deformation was observed. The uplift load–displacement curves exhibited a pronounced steep- transition pattern, and the axial strain of the grout body was mainly concentrated near the bearing plate and attenuated upward along the anchorage section. When the anchorage section extended into the moderately weathered rock stratum, strain attenuation became faster and interfacial load transfer became more efficient. Parametric analysis further indicates that the uplift bearing capacity increases approximately linearly with anchorage length before a critical anchorage length is reached, whereas the increase becomes much less significant beyond about 8 m. In addition, a proper increase in rock- socketed length can significantly improve the uplift bearing capacity. The findings provide useful reference for the design and optimization of uplift-resistant anchorage systems in transportation infrastructure founded in layered weathered rock.

Feng, Bing, Li, Panfeng, Zhou, Ji’an, Lv, Qing

Optimal Design and Analysis of Axial Gradient Buffer Structure Based on 2-DOF Flexible Hinge

2026-99-2356

10/30/2026

Conventional unmanned aerial vehicle (UAV) landing gears exhibit deficiencies including severe stress concentration, insufficient cushioning deformation capacity, and inadequate fatigue resistance during the landing impact process, which makes it difficult for them to meet the technical requirements of high-overload buffering conditions. Based on the elastic mechanics theory of the cantilever beam and using a two-degree-of-freedom (2-DOF) flexible hinge as the base, an analytical equation for the rotational stiffness of a 2-DOF flexible hinge in the direction was established. By combining the response surface methodology (RSM), the influence laws of key geometric parameters on the mechanical performance of the hinge were systematically analyzed. The optimal value range of the core structural parameters of this 2-DOF flexible hinge was determined as follows: the radius of the rounded corner R = 2.5 - 3.5 mm, the minimum thickness t = 1.5 - 2 mm, and the width a = 20 - 30 mm. Building on this foundation, an axial gradient columnar buffering structure incorporated with flexible hinges is proposed for the application of UAV landing buffering. Cross-verification between theoretical analysis and finite element simulation shows that the relative errors of structural deformation in each loading direction are merely 1.76% and 1.9%, respectively, which validates the accuracy and reliability of the proposed theoretical model. Parametric studies incorporating transient dynamic analyses under impact loading conditions elucidate that the maximal deflection and peak stress characteristics of the flexible hinge are positively correlated with the drop height and the structural connection angle. The outcomes of this research contribute a foundational theoretical framework and actionable technical support for facilitating the lightweight design and performance enhancement of flexible landing gears within high-load buffering systems of UAV.

Zhang, Qixian, Zhou, Jinhua, Zhang, Dongsheng, Wang, Jiashuai, Yang, Zengliang, Zhang, Yingxue

Machining Deformation Control of 5A06 Aluminum Alloy Aircraft Skin

2026-99-2343

10/30/2026

Aircraft skin is a critical external structural component that provides aerodynamic profile, sustains and transfers aerodynamic loads, and protects internal systems from harsh environments. High machining precision is essential to ensure assembly accuracy and flight performance. However, large scale thin walled skin components are prone to significant machining deformation due to their low stiffness. Traditional deformation control methods, which relying heavily on experiments and full-process simulations, are inefficient and costly for industrial applications. To address this issue, this paper establishes a correlation model among machining parameters, residual stress, equivalent bending moment, and machining deformation. Single-factor experiments are conducted to reveal the effects of spindle speed, feed rate, and cutting depth on surface residual stress. Based on plate-shell theory, the relationship between residual stress and equivalent bending moment is established. The quantitative relationship between equivalent bending moment and machining deformation of the skin is obtained via finite element simulation modeling. Finally, a deformation control strategy for the skin during finish machining is established by optimizing the cutting depth. Experimental results show that after parameter optimization, the overall machining deformation of the 5A06 aluminum alloy skin is reduced by 81%, and the maximum deformation is controlled within 0.17 mm, which fully meets the aeronautical assembly requirements. This work provides an efficient and low-cost process optimization strategy for the machining deformation control of large weak-stiffness thin-walled components.

Chen, Shu-Guang, Wang, Jing-Kai, Wu, Chao, Wang, Tian-Rui, Yuan, Hao

Vehicle Front-End Architecture as a Driving Factor in Occupant Injury Risk during Vehicle-Guardrail Impacts: A Hybrid III Dummy-Based Numerical Study

09-14-03-0011

10/26/2026

The performance of Midwest Guardrail Systems (MGS) during impact with electric vehicles (EVs) has raised concerns with recent observations demonstrating a higher susceptibility to rail failures. These failures are hypothesized to be related to EV-specific design, including variations in front-end geometry and inertial properties. Current guardrail evaluations rely on two vehicle types, a small car and a pickup truck, potentially overlooking sensitivity to front-end geometry variations, potentially leading to unanticipated impact responses. Additionally, the extent to which geometry influences occupant injury risks and trends during vehicle-guardrail impact remains insufficiently investigated. The objective of this study is to quantify the influence of vehicle front-end geometry on occupant injury risk during vehicle-guardrail impacts using finite element (FE) simulations. Occupant injury risk is analyzed using Hybrid III anthropomorphic test device (ATD)-based injury criteria and flail space-based vehicle severity metrics to identify trends and relationship between geometric variations and injury probability. Front-end geometry data from the Insurance Institute of Highway Safety (IIHS) were analyzed to identify parameters and ranges associated with adverse MGS performance. Based on vehicle alignment with the W-beam, hood leading-edge height, hood leading-edge angle, and bumper height were morphed on the Toyota Yaris model. A Latin Hypercube Design of Experiments generated 13 unique configurations for detailed analysis. Full-scale Manual for Assessing Safety Hardware (MASH) Test Level 3 FE simulations were then performed between the morphed vehicle models integrated with Hybrid III 50th percentile male ATD and MGS guardrail. Occupant injury metrics were evaluated alongside vehicle-based crash severity measures. All vehicle geometries fulfilled MASH criteria with occupant impact velocity (OIV) and occupant ride down acceleration (ORA) within tolerance with no rail rupture. Simulations suggest that probability of serious full-body injury (AIS3+) was estimated at 17.11% while probability of severe neck injury was the highest at 15.64% among the component level probabilities. While front-end geometry influences occupant kinematics, resulting injury metrics and vehicle-guardrail interaction characteristics, it does not independently govern occupant injury risk. Although, the MASH tests have the same outcome as the geometries studied, the changes in EV inertial properties could interact with the geometry leading to barrier failure, which will be explored in future work.

Bubna, Maheep, Buckland, Elijah, Riexinger, Luke E., Untaroiu, Costin

Deriving Representative Head-Impact Profiles in Contact Sports: A Shape-Based Clustering Approach

09-14-03-0018

10/26/2026

Instrumented mouthguards (iMGs) capture thousands of head acceleration events in contact sports, though processing the data from these into meaningful information remains a challenge. To bridge this gap, we developed a principled clustering pipeline to extract concise kinematics that are representative of real-world impact scenarios. We evaluated six multivariate time-series distance metrics using k-medoids clustering and a dataset of 5149 impacts across three sports: mixed martial arts, boxing, and rugby union. Model performance was evaluated using a Coverage Quality Score (CQS), prioritizing reconstruction coverage and cluster separation. Joint Shape-Based Distance (SBD) significantly outperformed all other metrics, including Dynamic Time Warping (DTW), driven primarily by superior reconstruction coverage. The methodology yielded two complementary archetypes. First, a 36-impact canonical set provides distinct medoids representing core kinematic mechanisms; however, distributional checks confirm these medoids alone do not reproduce cohort severity distributions. To resolve this, we generated a second, extended impact set sampled proportionally within clusters along specific severity axes (e.g., peak acceleration and whole-brain strain). This targeted sampling recovers full severity-distribution fidelity using fewer than 150 impacts per dataset. Ultimately, this framework successfully distills large iMG datasets into manageable cohorts providing a scalable solution for assessment, experimental targets, and finite element simulations.

Koumantou, Eleni, Chan, Emily Yik Kwan, Jones, Chris M., Austin, Kieran, Loosemore, Mike, Ghajari, Mazdak

Analysis of Structural Stress Distribution and High-Temperature Performance of Load-Bearing Components in External Fire Scenarios of Steel-Structured Aircraft Models

2026-99-2975

10/19/2026

This paper focuses on three typical external fire scenarios in aircraft firefighting and rescue training systems: engine fires, external fuselage skin fires, and nose landing gear fires. Unlike internal fires, these external fires expose the load-bearing steel structure directly to flame radiation and high-temperature environments, and the cooling methods and stress conditions associated with each fire scenario differ significantly. Based on the ABAQUS finite element platform, this study established a three-dimensional finite element model comprising an engine model, a water-cooled thermal insulation structure, and a fuselage support system, fully accounting for the actual structural layout and cooling protection measures of the training system. Material parameters were derived from measured performance data for Q355NH steel. The calculation results indicate that under the three types of external fire scenarios, the steel structure model maintained sufficient structural safety margins, with a minimum safety factor of 4.49 and a maximum of 9.43. This demonstrates that the current design meets the safety requirements for prolonged external fire training, providing a reliable mechanical basis for the safe operation of the ARFF training system.

Gao, Jianwei, Xu, Xiaodong, Huang, Min, Wang, Shumin, Shi, Yajie, Zhang, Yun

Coupled Vibration Analysis and Vibration Suppression for Spacecraft Multi-Panel Structures by Stiffness-Tunable Hinges

2026-99-2924

10/19/2026

Spacecraft hinged-panel structures feature a multi-hinged configuration, substantial dimensions, low stiffness, and low damping, making them susceptible to sustaining low-frequency vibrations under multi-source excitations. To address this challenge, a novel stiffness-tunable hinge is proposed for low frequency vibration attenuation. Firstly, the hinge structural geometry and stiffness-tunable principle are presented. Subsequently, FEM models of multi-panel structures incorporating stiffness-tunable hinges are developed. The natural frequencies and mode shapes of the system are investigated. Simulation results indicated that the multi-panel structures reveal bending vibrations, torsional vibrations, and coupled bending–torsional vibrations of the hinge-panel structure. Finally, a microgravity experimental platform was developed, this experimental platform offers several advantages, including extremely low friction, unconstrained horizontal motion, a compact structure, a small footprint, and robust reliability. The gravitational load of the hinged-panel is nearly counterbalanced, thereby enabling its unrestricted, omnidirectional translation across the horizontal plane. The experimental results rigorously validated the link between hinge stiffness-tuning and system eigen-frequency migration. Furthermore, vibration suppression at low frequencies of 0.29 Hz (for three-panel) and 0.31 Hz (for four-panel) was realized using non-contact magnetic excitation. This approach achieved amplitude reductions of approximately 9.70 dB at 0.29 Hz and 12.53 dB at 0.31 Hz. These findings demonstrate a novel strategy for suppressing low-frequency vibrations in spacecraft structures.

Bi, Zhiwei, Lin, Hui, Hu, Wei, Wang, Yufeng, Zhang, Ce, Yu, Ruijiang

Nonlinear Dynamic Modeling and Active Control of a Large-Scale Two-Dimensional Planar Phased Array Antenna

2026-99-2901

10/19/2026

A new method for dynamic modeling and active control of the large-scale, on-orbit assembled two-dimensional planar phased array antenna is proposed in this study. As the demand for high imaging accuracy and scanning coverage in satellite antennas increases, there is a shift toward larger apertures. However, large-scale phased array antennas face challenges such as low rigidity and significant nonlinear vibration during attitude maneuvers, which can degrade pointing accuracy and shape precision. To address these issues, this study proposes a dynamic modeling framework that incorporates geometric nonlinearity, employing finite element method (FEM) and a polynomial fitting-based model order reduction technique. A rigid-flexible coupling dynamic model is then developed based on the velocity variation principle. In control design, the paper integrates an active vibration control law using cable actuators with a computation torque algorithm based on control moment gyroscopes (CMGs) to design an integrated attitude-vibration control system. This system aims to suppress nonlinear vibration while achieving high-precision attitude control. Simulation results demonstrate the effectiveness of the proposed integrated control approach in both vibration suppression and attitude maneuvering, offering valuable insights for its practical application in future space missions.

Ma, Yihao, Liu, Xiang, Jin, Chaochen, Cai, Guoping

Multilevel Bayesian Model Updating for Satellite High-Stability Brackets Considering Welding Uncertainties

2026-99-2925

10/19/2026

The high-stability bracket is the primary component in remote sensing satellites responsible for carrying the camera and attitude control equipment; its dynamic behavior directly affects imaging quality and in-orbit service life. Welding-based connections introduce uncertainties during manufacturing and assembly, leading to significant discrepancies between finite element analysis results and experimental data. To quantitatively assess the impact of welding processes on the accuracy of the high-stability bracket’s finite element model(FEM), this study proposes a Bayesian parameter correction method based on Markov Chain Monte Carlo (MCMC) sampling and the Metropolis-Hastings (MH) algorithm. It employs a multilevel correction experimental framework—”material-level, component-level, and system-level”—to progressively refine material parameters and establish a high-fidelity FEM. First, the elastic modulus of the welded and non-welded regions were calculated using stress-strain curves obtained from static tensile tests on welded and non-welded plates; then, targeting the first two natural frequencies from dynamic impact tests on bar specimens, the material densities of the welded and non-welded regions were corrected using the Bayesian method; finally, the effectiveness of the correction method was verified through free vibration tests on the actual high-stability bracket. The results indicate that, compared to the undamaged region, the welded region exhibits a 13.87% loss in elastic modulus and a 55.32% loss in density. The relative errors in the first three natural frequencies of the corrected model were 0.59%, 0.01%, and 0.83%, respectively, verifying the high reliability of the proposed method in modal identification and providing a new technical approach for correcting spacecraft structural models.

Liu, Kun, Guo, Chongchong, Wu, Wenhua

Integrating MBSE with High-Fidelity Crash Simulation

2026-01-7542

9/22/2026

Modern electrified ground vehicles introduce complex, multi-domain safety requirements, such as post-crash thermal runaway prevention, that expose the traceability limitations of Document-Based Systems Engineering (DBSE). This paper proposes a four-layer, bidirectional digital thread architecture that integrates Model-Based Systems Engineering (MBSE) with high-fidelity, non-linear Computer-Aided Engineering (CAE) crash simulations. Leveraging SysML, System-Theoretic Process Analysis (STPA), and Python-based orchestration middleware, the framework automates the translation of descriptive safety requirements into explicit finite element boundary conditions. The architecture programmatically extracts key performance indicators from massive binary solver outputs and injects them back into the SysML environment for automated compliance verification. Demonstrated through a simplified electric vehicle side-pole impact case study utilizing LS-DYNA and a 1D thermal model, the framework successfully eliminates manual data handoffs, accelerates multidisciplinary design optimization, and ensures robust, risk-driven requirement traceability across the engineering lifecycle.

Rye, Patrick J.

Initial Thermal Evaluation of 422 Martensitic Stainless Steel Piston in a High-Output Diesel Engine

2026-01-7564

9/22/2026

A piston manufactured with a crown comprised of grade 422 martensitic stainless steel and skirt manufactured from 4140 steel was instrumented with fifteen thermocouples and a wireless telemetry system. Piston temperature data were collected at five engine operating conditions and compared to two additional instrumented pistons with crown and skirt both made of 4140 martensitic steel, which is traditionally used for heavy-duty diesel applications. Thermal finite element modeling was used to predict the increase in operating temperature of the 422 piston relative to the 4140 piston and help understand instrumentation uncertainty. Previous research of candidate high-temperature alloys indicated that 12Cr martensitic steel alloys, such as alloy 422, offer several potential benefits when used in a diesel piston application, including increased high-temperature oxidation resistance and strength. The potential benefits of alloy 422 may however be partially negated by the expected increased piston operating temperature due to the alloy’s lower thermal conductivity. In this work 422 alloy resulted in no statistically significant change in piston temperatures relative to the baseline 4140 steel during engine testing. The 422 alloy is poised to offer a dual durability advantage because the initial results show it can achieve superior oxidation resistance without operating at the higher temperatures that would accelerate such degradation. Maximum piston temperature capability is expected to be a critical design limit in next generation diesel engines with greater power density, lower heat rejection, and improved fuel economy. Citation: E. Gingrich, et. al., “Initial Thermal Evaluation of 422 Martensitic Stainless Steel Piston in a High-output Diesel Engine,” In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 11-13, 2026.

Gingrich, Eric, Tess, Michael, Grunin, Arkady, Korivi, Vamshi, Sebeck, Katherine, Pierce, Dean, Wang, Yiyu, Muralidharan, Govindarajan, Pillai, Rishi, Haynes, James A., Will, Kurt

Methods for Designing Rotating Components for Compliance to ISO 1940 Balance Requirements using Generic 3D CAD Software

2026-01-7565

9/22/2026

The benefits of specifying balance requirements in terms of an ISO 1940 balance quality grade instead of traditional mass-distance based requirements are discussed along with methods to convert ISO 1940 balance quality grades into permissible imbalance limits at the bearing supports. Methods are developed to determine the expected imbalance values at bearing supports using mass property data from generic 3D CAD software packages without the need for Finite Element Analysis. Practical exercises are presented using these methods to assess a part’s compliance to ISO 1940 while still in the conceptual 3D CAD design stage. These practical exercises cover the selection of appropriate geometric tolerances to ensure part balance without the need for post fabrication balancing as well as the design of nonsymmetrical components for ISO 1940 balance compliance. Citation: J. Srodawa, “Methods for Designing Rotating Components for Compliance to ISO 1940 Balance Requirements Using Generic 3D CAD Software,” In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 11-13, 2026.

Srodawa, John

Precision Simulation and Test of Drag Torque for Carbon Ceramic Disc Brakes with In-Wheel Electric Motor

2026-01-0813

9/14/2026

Aiming at the industry pain points of low simulation accuracy and lack of authoritative closed-loop experimental verification for the drag torque of special brake calipers for in-wheel electric motors, this study takes the hub motor-integrated carbon-ceramic inboard caliper as the research object. The inboard caliper layout has been realized on Protean’s in-wheel motor products [12], while the matching integration of the C/C-SiC brake disc with such an inboard structure for a compact hub-motor layout is original and covered by Chinese invention patent CN120207087A[15]. The inboard caliper is defined as a special brake structure installed on the inner side of the brake disc/hub motor cavity (distinguished from the traditional outboard caliper mounted on the outer side of the brake disc), which is specially adapted to the compact assembly space of in-wheel motors and realizes structural integration of braking and driving systems. This study proposes a high-precision finite element simulation method coupling the nonlinearity of piston seal material with bilateral parallel return springs. The simulation boundary conditions are calibrated by matching the bench test working conditions. To verify the simulation results, the drag torque bench test is carried out in accordance with the industry standard [13], realizing a complete closed loop of simulation modeling and experimental verification. Although a certain numerical deviation exists, the high consistency in core trends and key evolutionary nodes, together with a low error (≈5.6%) within the initial 0.9–1 rotation regime, demonstrates that the model reasonably reproduces the generation and attenuation mechanisms of drag torque during the early rotation stage.

Meng, Dejian, Liu, Yuqi, hu, Pengfei, Li, Birui, Shao, Jiyong

Thermomechanical Fatigue Life Prediction of Grey Cast Iron Brake Rotors Using Advanced Material Models and Elastic-Plastic Fracture Mechanics

2026-01-0816

9/14/2026

A unified thermomechanical fatigue (TMF) life-prediction methodology is presented for lamellar graphite (grey) cast iron brake rotors operating under the severe transient thermal loads that arise in brake dynamometer durability testing. The workflow links four ingredients within a single rotor-level framework: transient nonlinear finite-element analysis, temperature-dependent inelastic constitutive modeling, a mechanism-based short-crack TMF damage model, and an elastic-plastic (nonlinear) fracture-mechanics crack-growth simulation. Two constitutive descriptions are exercised for the structural analysis — the standard rate-dependent Chaboche viscoplastic model available in Abaqus, and a user material subroutine (UMAT) that couples Chaboche viscoplasticity with continuum damage in order to reproduce the tension–compression asymmetry of cast iron. The resulting stress, strain, and temperature histories drive a multiaxial thermomechanical fatigue Damage (DTMF) computation that estimates crack initiation and early extension, after which a nonlinear fracture-mechanics procedure simulates crack-front advance toward through-thickness failure. Both constitutive models correctly localize the crack-initiation site on the rotor inner diameter, consistent with the dynamometer observations; for the loading histories examined, the standard Chaboche model yields lives in closer agreement with test. The crack-growth simulation reproduces the rapid post-initiation propagation seen experimentally and resolves branch-wise differences in crack-front evolution through the rotor section.

Lee, Heewook, Garcia, Arnoldo, Liu, Yi, Hazime, Radwan, Boughanmi, Heni, Kassir, Abdallah

A Virtual Methodology to Define Air Tightness Criterion for Brake Calipers Based on Experimental Data

2026-01-0818

9/14/2026

Air tightness in brake calipers is a critical requirement for ensuring braking system reliability and safety. However, defining a clear and practical analytical criterion for air leakage prediction remains challenging due to the complex contact behavior at the seal–piston interface. This study presents a virtual methodology to define an air tightness criterion for brake calipers based on experimental evaluation and structural analysis. The seal squeeze ratio was selected as the primary design variable to evaluate its effect on sealing performance. Test samples with different seal squeeze ratios were manufactured, and air tightness was tested under controlled pneumatic pressure to determine when leakage occurred. In parallel, a finite element (FE) structural analysis was conducted to simulate the seal installation process and quantify the resultant contact pressure distribution between the seal and the piston surface. To support reliable structural analysis, preliminary experiments were performed to determine the hyperelastic properties of the seal elastomer. Furthermore, the seal squeezing force was experimentally verified. The experimental results showed that low seal squeeze ratio caused leakage, demonstrating that seal compression strongly affects sealing performance. Based on these observations, an analytical criterion was established using the contact pressure between seal and piston, with a minimum contact pressure defined to prevent air leakage. Although a direct quantitative correlation between air leakage and contact pressure was not determined, the proposed criterion provides a practical and physically meaningful basis for evaluating air tightness. This methodology allows designer to predict sealing performance during the product design, reducing a necessity for extensive testing and enabling more efficient and reliable brake caliper development.

Cho, Inyong, Kim, Beomseok

Design and Research of Large-Tire Replacement Robots

2026-99-1127

9/11/2026

In view of the large volume and weight of the tires of mining dump trucks and the difficulty in replacing them, a large tire replacement robot is proposed based on the tire parameters and the tire replacement process. The overall research scheme for the robot was developed using the functional analysis method, and the functional element solution and combination were completed. Based on the best solution obtained, a three-dimensional model of the tire changing robot was established using the SolidWorks software, followed by control system design and workflow analysis. To investigate the robot's operational kinematics, a simulation was conducted in the SolidWorks Motion module. The motion curve of the flipping platform during its operational state was obtained. A finite element simulation of the robot's front support beam was performed using ANSYS Workbench to obtain its stress and deformation contours under both no-load and heavy-load conditions. The structural parameters of the front support beam were optimized, focusing on its mechanical characteristics under heavy-load conditions, and the response surfaces of different parameters were obtained. The optimization yielded a 9.599 kg reduction in the mass of the front support beam. The maximum stress of the grasping mechanism under static simulation analysis is 50.617 MPa, with the maximum deformation of 0.4221 mm occurring at the end of the mechanical hand. Ground contact simulation for the robot's walking tires was conducted with Abaqus. Employing the Mooney-Rivlin hyperelastic model, this study investigated the mechanical response of the tire to static and dynamic loading, leading to the identification of the optimal operational load. The simulation results show that there is no interference among the various mechanisms of the large tire changing robot during operation. It can quickly complete the tire installation and removal tasks with precise control, and its strength and rigidity meet the requirements. This verifies the rationality and feasibility of the robot. The research on the large tire changing robot can provide a new approach for the maintenance of large transport vehicles such as mining dump trucks.

Tian, Liyong, Zhang, Haijian

Numerical Investigation of In-Plane Antisymmetric Failure Modes and Load-Carrying Mechanisms of Steel Portal Piers

2026-99-1594

9/11/2026

A nonlinear finite element model was applied to study the in-plane instability of steel portal piers, in which initial geometric imperfections, welding residual stresses, and material nonlinearity were considered. The modeling procedure was compared with experimental results from box-section members, and consistent tendencies in load level and deformation evolution were observed. In the numerical analyses, the initial elastic buckling configuration exhibited an in-plane antisymmetric form. As loading continued beyond the elastic range, this deformation pattern persisted. With further loading, the deformation remained purely axial while combining compression with bending. During this stage, plastic hinges appeared near the column tops, while lateral displacement became clearly observable. Comparison models with different geometric proportions show that variations in the span-to-height ratio and the beam–column stiffness ratio influence how instability develops and where plastic deformation tends to localize. From a design perspective, these trends can be considered when distinguishing instability characteristics and selecting stiffness proportions between beams and piers.

Li, Jie, Shangguan, Bing, Cheng, Zhangxu, Ruan, Furong, Bai, Fan

Research on the Design of Reconfigurable Assembly Fixture Frame for Aircraft Based on Rapid Manufacturing

2026-99-1409

9/11/2026

With the increasing demand for efficiency, flexibility, and cost-effectiveness in the aviation manufacturing industry, the prototyping cycles of aircraft development have significantly shortened. Traditional assembly fixtures, due to their high degree of customization and poor reconfigurability, struggle to meet the requirements for rapid prototyping of multiple aircraft models. To address this issue, research has been conducted on reconfigurable framework structures for aircraft assembly fixtures, and finite element analyses have been performed on different types of reconfigurable fixture frameworks. The study indicates that although the stiffness of reconfigurable frameworks is slightly lower than that of traditional welded framework structures, it still meets the requirements for rapid prototyping of development aircraft. By adopting standardized, low-cost reconfigurable assembly fixtures, the design and manufacturing cycle of tooling can be significantly shortened, and the reusability of tooling components can be enhanced, thus facilitating rapid and cost-effective development of prototype aircraft.

Wang, Xingzhong, Wang, Hongtao, Liu, Bing, Bi, Xinying, Liu, Zhanzhan

Numerical Calculation of The Ice-Breaking Resistance of the Icebreaker

2026-99-1517

9/11/2026

This study investigates the governing characteristics of ice resistance encountered by icebreakers operating in multi-year ice regions, with particular emphasis on the effects of bow truncation length, vessel speed, and ice thickness. A numerical simulation framework was developed using the finite element platform LS-PrePost to reproduce ice bending, failure, and ship–ice interaction throughout the icebreaking process. The numerical predictions were subsequently validated against physical model test data. The results indicate that ice resistance exhibits an increasing trend as the bow truncation length, navigation speed, and ice thickness increase. The ice resistance of different bow truncation lengths in the multi-year ice area is different. By truncating the model ship at different positions from the bow and analyzing the ratio of the ice resistance of the truncated models to that of the full-scale model, researchers can better understand the effects of bow size. This can provide a theoretical basis for conducting ice resistance tests with truncated model ships in a limited-scale ice water tank, and has certain practical value for the design and optimization of the icebreaker’s hull lines.

Liu, Yanwei, Zhang, Xiufeng, Yu, Yingjie, Wang, Lucai, Zhao, Weihang

Loosening Behavior of Flared Tube Fittings under Transversal Vibration Conditions

2026-99-1113

9/11/2026

Flared tube fittings are extensively utilized in pipeline systems due to their effective connection and sealing capabilities. However, during practical service conditions, transversal vibration frequently induces thread loosening, subsequently leading to seal failure and other malfunctions. Current research lacks a systematic investigation into the loosening behavior of flared tube fittings under transversal vibration conditions. This study establishes a precise finite element model of the flared tube fitting and systematically examines its loosening behavior under stress redistribution, plastic deformation, and fretting wear conditions by simulating the assembly process and applying cyclic transversal vibration loads. The research findings demonstrate that the loosening process of flared tube fittings occurs in two distinct stages. The initial stage primarily involves preload reduction caused by non-rotational factors such as stress redistribution, while the subsequent stage features continuous preload attenuation resulting from relative rotation between internal and external threads. Notably, a critical amplitude has been identified. When the actual transversal amplitude remains below this critical value, only non-rotational loosening occurs in the flared tube fitting, with no rotational loosening taking place. Further investigation into factors affecting the critical amplitude, including preload, friction coefficient, material properties, and thread type, reveals that preload, friction coefficient, and material elastic modulus significantly influence the critical amplitude, whereas thread type demonstrates a negligible impact. These findings provide valuable insights for enhancing the reliability of flared tube fittings in vibration-prone applications.

Liu, Chang, Li, Muxiao, Chen, Hanlin, Xu, Dong, Gong, Zhengchao

Structural Airworthiness and Mechanical Characteristics Analysis of Real-Time Flight Data Acquisition Equipment

2026-99-1411

9/11/2026

The rising complexity of civil aviation and recent incidents, including Sichuan Airlines “14 May” and China Eastern Airlines “21 March,” highlight the urgent need for real-time flight data acquisition systems to support timely safety monitoring and early warning. Current methods rely mainly on post-flight data, while real-time monitoring remains constrained by limited bandwidth and insufficient device capabilities. This study presents a comprehensive structural and mechanical analysis of a real-time flight data acquisition device designed according to ARINC-600 standards and airworthiness regulations (ED112A, DO-160G). The device integrates data acquisition, storage, processing, and power modules, utilizing a Xilinx Zynq UltraScale™ platform for hardware-software co-processing, enabling high-speed data parsing, time synchronization, encryption, redundant storage, and secure transmission. Finite element modal analysis was performed to evaluate the structural airworthiness and vibration characteristics. The first ten natural frequencies range from 246.41 Hz to 1109.2 Hz, significantly exceeding typical aerospace excitation frequencies, effectively preventing resonance under operational conditions. Mode shape analysis indicates an evolution from low-order global bending and torsion to high-order local complex deformations, revealing relative stiffness weaknesses at panels and connection points, providing guidance for structural optimization. The study establishes a closed-loop framework connecting mechanical characterization, data security, and equipment reliability. Combined simulation and experimental validation ensures accurate assessment of dynamic performance, supporting operational robustness and airworthiness. The findings not only advance the development of high-performance real-time flight data acquisition systems but also enhance risk identification, early warning, and overall flight safety management in civil aviation.

Xu, Xiaodong, Gao, Jianwei, Guo, Qiang, Zhang, Yun, Kong, Xiangjun

Study on Water Hammer Effect of an Aircraft Composite Fuel Tank under High-Speed Impact of Multiple Fragments

2026-99-1420

9/11/2026

The investigation examines the damage mechanisms of composite fuel tanks under high-speed impact by multiple fragments utilizing a fluid-solid coupling finite element approach. The Arbitrary Lagrangian Eulerian (ALE) algorithm is used to simulate the single-box composite fuel tank under the impact of different distribution distances of fragments by using the software LS-DYNA. The cavity evolution and the panel deformation of the composite fuel tank are analyzed in detail. The findings indicate that the water hammer effect amplifies the extent of damage to the composite fuel tank structure. During the initial phase following fragment impact, a cavity forms within the tank. The resulting rise in the pressure difference between the interior and exterior of the tank causes the liquid to impinge on the impacted panel, leading to its deformation. In the later stage, due to the large degree of damage to the incident panel, there is a certain degree of pressure relief inside the fuel tank, the degree of water hammer effect is obviously reduced, and the cavity in the fuel tank gradually disappears. The distribution distance of the fragments has a great influence on the damage effect of the fuel tank. As the spacing between fragments diminishes, their effects become more concentrated. This results in increased force from the liquid on the fuel tank panel, leading to greater deformation and more severe damage to the panel.

Wang, Ruiwen, Song, Yahui, Li, Chengwang

Numerical Simulation Study on the Influence of Explosive Shape on the Dynamic Response of Tracked Vehicles

2026-99-1103

9/11/2026

This study utilizes finite element analysis and a multi-material arbitrary Lagrangian-Eulerian (ALE) formulation to systematically investigate the dynamic responses of tracked armored vehicles under underbody blast loading from cylindrical, spherical, and cubic charges. Numerical results indicate that, given equivalent charge masses and detonation distances, the shape of the explosive geometry significantly affects shock wave propagation characteristics and the subsequent structural response behavior. Compared to the other two charge configurations, the cylindrical charge exhibits superior shock propagation velocity and a more rapid dynamic response time in the vertical direction. Consequently, the cylindrical charge induces a maximum elastic displacement of 114.9 mm in the underbody structure—surpassing the cubic and spherical charges by factors of 1.16 and 1.18, respectively—while significantly intensifying near-field overpressure.

Tang, Jing, Fu, Tiaoqi, Liu, Yong, Feng, Yu, Sun, Xiaowang

Study on Temperature Rise and Heat Dissipation of Micro Electric Vehicle Drive Motor Based on Multi-Physics Coupling

2026-99-1131

9/11/2026

This paper is mainly about heat dissipation and improvement technology, aiming at solving the problem that the driving motor of 4 low-speed electric vehicles has too high a rising speed when running under complicated working conditions. Core losses and conductor losses are calculated by using the finite element method as well as known empirical formulas, and magnetic eddy loss at three operating conditions (normal condition, maximum speed, and peak torque. The computed heat loads are then used to establish the complete 3- dimensional model of thermal analysis. As shown in Figure 3, without active cooling, the hottest conductors would be at about 141°C (Class-B Insulation limit). Therefore, three different liquid cooling designs (helical channel, serpent channel, and annular flow) have been designed and analyzed. A coupled thermal- fluid simulation has been performed on the helix structure, which showed better results, so we selected it to be optimized. The optimization is performed using central composite design, genetic algorithms for response surfaces, and multi-objective evolutionary optimization (NSGA-II). The objective function is to simultaneously achieve a low maximum working temperature as well as good heat transfer properties by changing the geometry of cooling channels. The cooling of the motor as well as the suction pressure was optimized, after which a decrease by up to 31.1°C (up 8.6% on the maximum temperature) was observed. Also, pressure drop reduction as much as 23% along with substantial increases in both the heat transfer performance and reliability.

Xi, Heyuan, Bai, Enjun, Ma, Wenyu, Tang, Fuyu, Liu, Zhiyi

Fatigue Damage Analysis of a Wheeled Vehicle

2026-99-1207

9/4/2026

This article studies the fatigue damage problem of vehicles under air drop and off-road conditions. First, a multi-body dynamics model of the entire vehicle is established in ADAMS/View to obtain loads and center-of-gravity acceleration under off-road conditions. Subsequently, a finite element model of the vehicle air drop is created in HyperMesh and LS-DYNA to simulate the landing impact and extract loads on key components. By superimposing and spectrum processing the loads from the two conditions, a vehicle load spectrum is compiled and used as input for fatigue analysis. Based on the Miner linear cumulative damage criterion and the material S–N curve, fatigue life predictions are made for key areas of the frame and suspension. The results indicate that the front cross beam and auxiliary longitudinal beam at the bottom of the frame are the most vulnerable components, with the auxiliary longitudinal beam reaching failure under both conditions, but having a limited impact on the overall vehicle operation. Although the peak acceleration under air drop conditions is higher, the off-road conditions lead to more severe cumulative damage due to higher impact frequency and duration. This study provides references for vehicle structural optimization and service reliability enhancement.

Lin, Qingpeng, Zhang, Qiang, Fu, Lei, Huang, Jianbing, Qin, Weiwei, Sun, Xiaowang

A Computing Method of Splitting Factor for 3D Non-Compatible Generalised Mixed Hexahedral Element

2026-99-1211

9/4/2026

With the rapid development of the aerospace industry, FEM has been widely applied as a key tool. However, the high complexity of aircraft and spacecraft geometries and structures often leads to unavoidable distorted meshes in FEM, which significantly degrades the accuracy of analysis results. Both the splitting factor and the mesh distortion significantly affect the accuracy of the generalised mixed elements. The coefficient matrix deviation between the distorted element and the standard element was quantified. Thus, the computing equation for a three-dimensional (3D) hexahedral distorted element’s splitting factor was constructed. Examples were used to validate the proposed method. For distorted meshes, the accuracy of NCGME has been improved.

Shen, Ao, Qing, Guanghui

Experimental Testing and Finite Element Simulation on Tensile Mechanical Behavior of Nickel-based Superalloys

2026-99-1224

9/4/2026

The accurate prediction of high-temperature mechanical behavior of GH3230, as a core material for the new generation of combustion chambers in China, is a key technical prerequisite for promoting engineering applications. This article is the first to conduct a systematic study on the tensile properties of the alloy at three typical service temperatures of 200°C, 550°C, and 900°C, combining high- temperature tensile testing with numerical simulation. Through metallographic observation, the excellent microstructure characteristics of the alloy, including no grain boundary defects, inclusion phase size less than 5 μm, and uniform distribution, were clarified. Based on this, a multi-temperature adaptive tensile simulation model was established. Experimental verification showed that the model can accurately reproduce stress-strain tensile curves at different temperatures, with prediction errors controlled within a reasonable range, effectively breaking through the limitations of traditional single-temperature simulation. This study not only provides an efficient and accurate new method for the performance analysis and safety evaluation of GH3230 in a wide temperature range but also provides practical technical means to support the component-level engineering application of this material. At the same time, the research results also provide a reference technical path and research ideas for the multi-temperature mechanical performance prediction of other nickel-based high-temperature alloys.

Qiao, Yongle, Xie, Jiahui, Li, Lei, Zhou, Jie, Zhu, Yankun, Wang, Yifei

High-Precision Micro-Satellite Attitude Control: Design and Testing of an Ultrasonic Motor-Driven Control Moment Gyroscope

2026-99-1291

9/4/2026

The issues associated with the traditional single-gimbal control moment gyroscope (SGCMG) driven by electromagnetic motors, such as complex structure, significant gear backlash, weak anti- interference capability, poor adaptability to space environments, and large volume and weight, make it difficult to meet the attitude control requirements of micro/nano satellites. To address these issues, this paper proposes an SGCMG design based on a rotary traveling wave ultrasonic motor (RTWUM) drive. Ultrasonic motors offer advantages including high torque, fast response, self-locking upon power-off, immunity to electromagnetic interference, and simple structure, making them suitable for spacecraft attitude control systems. This paper elaborates on the working principle and structural design of the ultrasonic motor, covering the entire process from stator modal optimization, flywheel and gimbal structural design to system integration and control system implementation. Through finite element analysis and experimental verification, the designed ultrasonic motor-driven SGCMG meets the requirements of micro/nano satellites in terms of output torque, speed control accuracy, and structural compactness, demonstrating the promising application prospects of ultrasonic motors in aerospace attitude control.

Wu, Jintao, Zhang, Jiyang, Li, Huafeng, Pan, Song

Aerodynamic Load Calculation and Prediction Method for Folded Wing Mechanism

2026-99-1289

9/4/2026

The folding wing mechanism is widely used in aircraft design. Whether the folding wing surface can unfold smoothly determines whether the aircraft can fly normally. Therefore, studying the aerodynamic loads and structural deformations during the unfolding process of folded wing surfaces is very important. The motion process of a folded wing mechanism is a typical fluid-structure interaction (FSI) process. During deployment, the wing surface moves under the combined action of the actuator’s pull and the aerodynamic loads from the incoming flow, while the large deformation of the wing surface during its movement, in turn, affects the aerodynamic loads on the mechanism from the flow field. Considering the FSI effects during the unfolded motion process of the folded wing, simulation was conducted using the ALE algorithm in LS-DYNA to obtain the kinematic and dynamic parameters in the unfolded motion process, and also to get the aerodynamic torque on the wing under different angles and angular velocities. In practical engineering applications, the actuation force of the deployment mechanism can vary due to factors such as the amount and performance of the pyrotechnic material. Consequently, the final velocity and the whole motion process of the wing mechanism will also change. For the calculation of aerodynamic external loads under multiple operating conditions, using the ALE algorithm will consume a large amount of computational time and cost. Given the high computational cost and long computation time of finite element simulations, a BP neural network was established to calculate the aerodynamic loads on the wing surface under different actuation forces. This allows for a rapid assessment of whether significant deformation or damage will occur to the folding mechanism or nearby components during the deployment process.

Wei, Ting, Li, Naitian, Tong, Zongkai

The Flexibility Coefficient Fitting of Bolt in Metal-Composite Hybrid Joint Structures Based on L-M Method

2026-99-1267

9/4/2026

This study used the L-M (Levenberg-Marquardt) algorithm to analyze the fitting of the flexibility coefficient of fasteners in the mixed connection structure of metal composite materials to address key challenges in aircraft structural design. Through parametric modeling and finite element simulation of single lap joints, the system evaluates eight key factors, including the direction of the composite material layer, the elastic modulus of the metal plate, the plate thickness ratio, the fastener diameter, the elastic modulus of the fastener, the Poisson’s ratio of the fastener, the magnitude of the preload force, and the type of bolt configuration, covering convex and countersunk variants. Advanced material modeling techniques are introduced in the study to accurately capture the anisotropic behavior of the composite material layer and its interaction with metal components under different load conditions. The results show that the higher modulus and thickness of the composite material plate and metal plate significantly reduce the flexibility of fasteners, and larger fastener diameters are associated with reinforcement. The elastic modulus further reduces flexibility. The flexibility of convex head bolts is significantly lower than that of countersunk head bolts, while Poisson’s ratio, preload force, and humidity have little effect. Based on these findings, a new flexible calculation formula containing nine undetermined parameters is proposed. The L-M algorithm is used for nonlinear regression to derive formulas with physical significance. The verification shows that the proposed formula is highly consistent with the finite element results, with a corrected coefficient of determination of 0.956. Among 864 test sample points, 73.61% have an error of less than 5%, and only 0.23% have a deviation of more than 15%. Comparative analysis with twelve existing methods, including the Delft University and Boeing formulas, confirms that the proposed method has better accuracy. This method effectively expands the applicability of traditional flexible formulas, provides solid theoretical support for advanced aircraft connection design, and realizes diverse mixing in aerospace engineering and accurate calculation of connection configuration.

Fan, Zhuotao, Wang, Xu, Wang, Tong, Li, Xianchao

An Experimental and Numerical Study on the Optimization of Quasi-static Energy Absorption Performance in Aluminum Alloy Thin-walled Tubes with Varied Notch Configurations

2026-99-1255

9/4/2026

Aluminum alloy thin-walled tubular parts play an important role in the energy absorbing elements of automotive passive safety. The number of geometry-trigger based notches is a factor in alleviate the initial force peak and shift the progressive buckling mode. However, until now, only limited work has been reported considering multiple notches. It is hard to clearly understand the impacts of the number of triggers on the buckling behavior and thresholds. Here, a mixture of quasi-static axial compression testing with high-fidelity finite element simulations is used to explore the influence of elliptical perforation number on AA6061-T6 tube crushing behaviour. For the first time, it is demonstrated that increasing the perforations leads to non-monotonic buckling evolution: from symmetry increasing → asymmetrical instability → optimal re-symmetrization → excessive weakening. We observe this transition from isolated holes to a collective “weakening hoop” controlling symmetric buckling as the number of holes increases. Our results give optima for separate objectives; T6 offers the best overall crashworthiness (45.2% less maximum force), with the other measures showing T4 with the best stiffness. We determine quantitative relationships between the number of holes and corresponding performance metrics. This gives practical design criteria for the design of energy absorbers.

Guo, Zifa, Jin, Ming

Design and Analysis of Transmission Line Tower Erection Equipment

2026-99-1240

9/4/2026

In response to the industry's problems of transportation difficulties, low efficiency, and high safety risks during the erection of high-voltage transmission line towers in mountainous areas, this paper proposes a light tower erection device that integrates connection, assembly, and fixing functions. The device adopts 180 mm Q345 equal-angle steel tower legs and is equipped with a hydraulic drive system. The tower body is raised through the coordinated work of the main and secondary hydraulic cylinders. In contrast, the vertical and horizontal hydraulic cylinders are used for auxiliary descent and precise fine adjustment. Its modular and lightweight structural design meets the transportation needs in narrow spaces in mountainous areas. The specifications of the hydraulic cylinder are determined by mechanical calculation, and the structural strength of the square tube and the main and secondary hydraulic cylinder connecting rods is verified by finite element analysis. Kinematic simulation confirms that the operating performance of the device is stable. This device provides an efficient and reliable piece of technical equipment for the construction of transmission lines in mountainous areas, which has important engineering application value and broad promotion and application prospects.

Li, Hailong, Chen, Zhen, He, Longping, Wang, Zhongpan, Li, Cheng

Extreme-Condition Analysis of Flow and Structural Strength in a Closed Space

2026-99-1276

9/4/2026

This study investigates the transient Fluid-Solid-Thermal (F-S-T) multi-physics coupling behavior of a direct-acting reversible check valve under extreme working conditions in a closed environment. The valve operates within a military system, functioning for gas addition and resisting explosive reactions, where its internal chamber experiences rapid transitions to ultra-high temperature (2000°C) and ultra-high pressure (800 MPa). Given the threat posed by such transient impingement to the structural strength of the pressure-bearing components, a detailed study is essential. A coupled numerical simulation is employed, utilizing Ansys Fluent for Computational Fluid Dynamics (CFD) and Ansys Mechanical for Finite Element Analysis (FEA). A three-dimensional, compressible, Navier-Stokes model and F-S-T coupling governing equations are established to simulate the transient flow field and transient structural field. Results indicate that the Impinging Flow Field (IFF) exhibits a highly unsteady state due to fluid inertia and aggregation-recoil effects, with local pressure peaks reaching 1590 MPa. The temperature field shows marked hysteresis relative to pressure and develops pronounced thermal stratification. The equivalent stress distribution closely follows the transient fluid pressure in the Impinging Structure Field (ISF), confirming strong F-S-T coupling. Although localized areas, particularly near the outlet region and specific inner walls, experience stresses exceeding the yield strength and enter the plastic stage, the overall valve structure remains intact, with stress levels staying within the material's ultimate bearing capacity. This research demonstrates the viability of the adopted coupled simulation methodology for analyzing extreme transient events. The findings provide a valuable reference for the safety design and assessment of valves operating in similar extreme environments.

Lai, Fangye, Wang, Xuesheng

Stress-Strain Response Characteristics of Buried Gas Pipelines Under Landslide Action

2026-99-1275

9/4/2026

Typically, triggered by geological hazards such as landslides, ground displacement acts as the main cause for the failure of buried pipelines. To maintain the structural integrity of these pipelines, an in-depth investigation is required to understand how these pipelines, subjected to landslide thrust, respond mechanically. During the research, a refined three-dimensional (3D) finite element model for soil-pipeline interaction was established, as evidenced by existing experimental data, which takes the elastoplastic behavior of the soil and complex contact conditions into consideration. According to a thorough parametric study, on the basis of the model, the effects of pipeline, landslide, and soil vary in their protection, detrimental, and complex trade-off levels. On the one hand, protective measures concerning wall thickness, steel grade, and other similar factors serve to improve resilience; on the other hand, detrimental factors such as burial depth and soil stiffness escalate the possibility of failure risk. Notably, the influences related to landslide extent and pipe diameter are not straightforward and monotonic. In other words, when one factor increases, risk may be reduced in one regime and amplified in another. Therefore, words like “wider” or “bigger” should not be equal to “safer” by default. To conclude, based on the results, train-based evaluation is supported, and some practical guidance can be provided for the design and risk assessment for pipelines in areas where geohazards may occur.

Zhang, Ruijia, Dong, Shaocan, Wang, Xinyu, Li, Yuxing, Hu, Qihui, Wang, Wuchang

Investigation into the Crashworthiness of Freight Vehicles under Frontal Impact

2026-99-1286

9/4/2026

This paper investigates the crashworthiness of freight vehicles under frontal impact based on the C-NCAP (China New Car Assessment Program) standard. Explicit dynamics and finite element methods were employed to conduct simulation analyses of the impact event, with the aim of offering references for improving vehicle crashworthiness. The findings indicate that the vehicle cabin remains largely intact, providing sufficient survival space for occupants. However, increased load amplifies the impact impulse and reduces crashworthiness. Additionally, the use of an enhanced anti-collision beam helps distribute impact forces and lowers the peak impact load.

Liu, Zihan, Jiang, Yi, Wang, Pu

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