Browse Topic: Analysis methodologies

Items (10,592)
Find
Johnson-Cook Model Calibration of 10# Steel and Dynamic Mechanical Behavior Analysis under High Strain Rates2026-99-12019/4/2026
As a typical material for fragmentation warheads, the mechanical behavior and ballistic penetration performance of 10# steel are critical for assessing warhead lethality. To characterize the dynamic response of 10# steel, systematic experiments were conducted, including quasi-static tensile tests, split-Hopkinson tensile bar tests, and thermal softening measurements. A = 505.46 MPa, B = 292.84 MPa, n = 0.335, C = 0.0343, and m = 1.213 are the calibrated Johnson–Cook parameters. Bridgman-corrected notched tensile tests determined damage parameters D1 to D4: 0.065, 0.746, −0.646, and 0.031). A study of its constitutive behavior shows that the strength of 10# steel increases with stress triaxiality and strain rate, whereas increasing temperature enhances ductility and reduces strength. Finite element software was updated to include the calibrated parameters to develop a material model for ballistic impact simulation. When compared with the ballistic penetration test results obtained using a 14.5 mm projectile, the simulated residual velocities show less than 5% deviation from the measured values. 3D scanning reveals that fragment sizes in experimental data differ by under 10% from simulation predictions. This work enables precise numerical simulations for warhead fragmentation prediction and lightweight armor design.
Tian, Yumo, Zhang, Longhui, An, Fengjiang, Feng, Bo
The Vacuum System of Arc Section Standard Cell for STCF Collider Rings2026-99-12389/4/2026
The Super Tau-Charm Facility (STCF) is a new-generation positron-electron collider planned in China. The core mission of STCF is to design a new generation of large-scale scientific facility featuring a center-of-mass energy between 2 and 7 GeV and a peak luminosity of more than 5×10^31 cm^–2s^–1. Given its high beam intensity and high luminosity characteristics. This will provide serious difficulties for the vacuum system’s design due to its high beam intensity and high luminosity features. The double-ring collider and the injector are the two primary components of the STCF. Each collider ring is divided into arcs, straight sections, and the interaction region. The arc sections adopt the same standard cell design. This paper primarily introduces the vacuum system of a standard cell for the arc section. This is related to the space simulation of aerospace on the ground, which requires a very high vacuum. By designing an overall scheme for the vacuum system, the structure and dimensions of the vacuum chamber are determined. The synchrotron radiation power and dynamic gas load distribution are calculated for the Arc Dipole Magnet. The placement scheme for vacuum components such as vacuum pumps, bellows, and BPMs is determined. At the same time, simulation analysis was conducted on the temperature, strength, and internal pressure of the vacuum chamber using finite element analysis software. Different vacuum chamber materials will have different calculation results, and the copper vacuum chamber is selected in this paper. The design specifications meet the technical requirements proposed by the physical system, providing a theoretical basis for the development of the next prototype and technical guidance for the design of vacuum systems in other sections.
Zhao, Lijuan, Zhang, Ruiyang, Sun, Kun, Gong, Hailiang, Jiao, Weijie, Zhang, Benfu, Mao, Mingyang
Numerical Analysis of the Frequency Acceleration Effect on the Aerodynamic Efficiency of 3-DoFs Flapping Wing2026-99-12889/4/2026
This study examines how frequency acceleration affects the aerodynamic efficiency of a forward flying airfoil by establishing a kinematic model and conducting numerical simulations using the NACA0012 model. Since the aerodynamic force coefficients have been obtained in previous studies, this paper directly utilizes these coefficients to evaluate the effects of different frequency acceleration combinations on aerodynamic efficiency. It is concluded that under the condition of no pitch frequency acceleration, the combination of positive plunging frequency acceleration and sweep frequency acceleration significantly reduces the lift efficiency from 89.7% (under no frequency acceleration) to 18.1%, and can increase the propulsion efficiency from 44.1% (under no frequency acceleration) to 75.5%. Furthermore, under the AM-8 condition, the lift efficiency shows a decreasing trend as the acceleration factor increases. The analysis and investigation of frequency acceleration effect provide a theoretical foundation for enhancing the aerodynamic performance and optimizing the structural design of flapping wing drones.
Kong, Fanwei, Qu, Ligang, Li, Zhandong, Li, Jing, Lao, Yile
Aerodynamic Load Calculation and Prediction Method for Folded Wing Mechanism2026-99-12899/4/2026
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
High-Precision Micro-Satellite Attitude Control: Design and Testing of an Ultrasonic Motor-Driven Control Moment Gyroscope2026-99-12919/4/2026
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
Research on Scalelike Adaptive Suction Flow for Wide-Speed Range Hypersonic Inlets2026-99-12529/4/2026
As critical components of aircraft, hypersonic inlets utilize shock wave compression effects to pressurize incoming flow. The interaction between shock waves and the boundary layer tends to generate separation zones, and it adversely affects inlet performance. As a method to significantly enhance inlet performance, suction technology can substantially reduce the size of separation zones when they form in the inlet. However, when the inlet is started and operating normally, suction configurations may cause mainstream leakage and make it difficult to meet the requirements of inlets with wider speed ranges. This paper designs an adaptive scaliform suction structure that utilizes a lift-generating design to induce a slight upward deflection of high-speed near-wall flow. It can reduce high-speed mainstream leakage without compromising the effectiveness in low-speed separation zones. Numerical simulations are employed to evaluate its suction performance in both inlet separation zone flow fields and supersonic mainstream flow fields. The internal flow mechanisms of the scaliform suction structure are investigated, and differences in its behavior across various suction flow fields, as well as its interference with the mainstream, are discussed. The study reveals that when the height of the scaliform suction structure is approximately 1/8 of the incoming flow’s velocity boundary layer height, the suction flow coefficient in the separation zone is twice that in the hypersonic mainstream. Furthermore, the loss in Mach number and total pressure recovery coefficient of the near-wall supersonic mainstream is controlled within 5%. This structure exhibits an adaptive suction capability for separation zones, thereby extending the starting speed range of the inlet.
Zhao, Xuening, Zhao, Yilong
Design and Analysis of Transmission Line Tower Erection Equipment2026-99-12409/4/2026
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
The Flexibility Coefficient Fitting of Bolt in Metal-Composite Hybrid Joint Structures Based on L-M Method2026-99-12679/4/2026
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 Configurations2026-99-12559/4/2026
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
A Method of Hamiltonian System for the Vibration Problem of Cracked Plates with Piecewise Boundaries2026-99-12599/4/2026
This paper focuses on analytical solutions for studying the vibrations of partially cracked orthotropic plates with piecewise boundaries using the symplectic elasticity method. Crack compliance coefficients are derived from the line spring model and introduced into the governing equations. In this paper, by establishing the Hamiltonian system and solving the Hamiltonian canonical equations, the vibration problem of cracked plates with piecewise boundaries can be reduced to finding the symplectic eigenvalues and symplectic eigensolutions. In the Hamiltonian system, the problem is transformed into seeking the solution of an algebraic equation system by the aid of symplectic eigensolutions and the adjoint symplectic orthogonal relations between the eigensolutions. Thus, for orthotropic plates with cracks under piecewise boundary conditions, this work presents a set of analytical solutions. Specifically, expressions for the free vibration behavior are derived. Furthermore, the steady-state response is determined. Finally, the transient dynamic response is also formulated and solved. The numerical results show that this method is effective and the natural frequency obtained in this paper is consistent with experimental results. A parametric investigation is performed, with the aim of comprehensively investigating the dynamic behavior of cracked plates subjected to piecewise boundaries. Significant findings include how aspect ratio, piecewise boundary conditions, and crack length affect structural vibration characteristics. For the plates containing cracks under piecewise boundaries, the frequency-response and the time-history curves for the forced vibration are plotted. These curves clearly illustrate the corresponding vibration characteristics of the plates. Some of the results can provide benchmarks for validating numerical or approximate methods. The method presented in this paper can provide a pathway for solving similar problems in the field.
Qu, Jianlong, Yu, Qinyu, Jia, Jufang, Xu, Xinsheng
Experimental Testing and Finite Element Simulation on Tensile Mechanical Behavior of Nickel-based Superalloys2026-99-12249/4/2026
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
Research and Analysis of Civil Aircraft Radio Altimeter Malfunction2026-99-12359/4/2026
The radio altimeter is an important navigation instrument on an aircraft, capable of accurately measuring the aircraft's true height above the ground or sea to ensure safe flight. This capability is crucial for ensuring normal flight operations, especially during critical phases such as takeoff, approach, and landing. Polar terrain is complex and continually changing. The vast, endless ice fields, crisscrossing glacier crevasses, towering icebergs, and weather conditions all add significant uncertainty to air travel. In such environments, the aircraft's navigation system is particularly important as a core device to ensure flight safety. This article provides a brief overview of the aircraft radio altimeter system. Using data and observations from production flight tests, it studies the specific challenges posed by radio altimeter failures encountered during these critical validation flights. The study synthesizes these findings and proposes a relatively general troubleshooting approach to address such issues. Furthermore, the effectiveness of this method has been rigorously validated through its application in solving a complex real-world radar altimeter failure case.
Song, Mingming, Mi, Yujie
A Computing Method of Splitting Factor for 3D Non-Compatible Generalised Mixed Hexahedral Element2026-99-12119/4/2026
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
Fatigue Damage Analysis of a Wheeled Vehicle2026-99-12079/4/2026
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
Traffic-Load Fragility Assessment of Prestressed Concrete Hollow Slab Bridges Considering Load Characteristics2026-99-12999/4/2026
Assessing the vulnerability of bridges to traffic loads is critical for ensuring their long-term operational safety. The reliability of bridges under design vehicle loads or simulated random traffic flows constitutes the primary focus of existing research. Current research often lacks analysis that incorporates actual traffic load conditions. This paper proposes a traffic-load fragility assessment method for prestressed concrete hollow slab bridges considering load characteristics. The methodology integrates Metropolis-Hasting sampling algorithm with Copula functions to simulate random traffic flow, calculates resistance levels corresponding to structural cracking, yield, and failure states, and employs Monte Carlo sampling for failure probability calculation. Finally, a case study of four prestressed concrete hollow slab bridges is conducted to analyze their traffic load fragility. The results show that, under the same traffic load characteristics, different bridges have varying vulnerabilities corresponding to different failure states. The traffic-load fragility assessment approach put forward in this study can offer important technical support for both bridge design work and the development of vehicle load restriction policies.
Zhou, Yihang, Yang, Gan
Fluid-Structure Interaction Analysis of 150 m Wind-Turbine Concrete Tower2026-99-12959/4/2026
Wind turbines equipped with large blades significantly enhance power generation efficiency. For large turbines reaching 150 meters in height, concrete towers offer an effective means of cost savings. Nevertheless, the stability of such structures must be carefully considered, given that wind perturbations are amplified with increased height. In this study, we aim to develop a numerical approach for conducting fluid-structure interaction (FSI) analysis on a 150-meter wind turbine concrete tower. A two-way FSI analysis method has been developed using the immersed boundary method, effectively addressing the coupling effects between the structural and fluid models without the need for body-fitted meshing. Our numerical results demonstrate that the proposed method achieves stable convergence and accurately captures dynamic structural responses under high-speed wind conditions. This method will contribute to the numerical design and safety validation of wind turbine infrastructure in engineering projects.
Gan, Shishun, Li, Hao, Chu, Hao, Lin, Yiyang, Wang, Ban
Experiments on Effects of Self-Locking on Mechanical Response of Origami Metamaterials2026-99-12069/4/2026
Motivated by the negative Poisson’s ratio tetrahedral-trihedral polyhedron (TMP), this study systematically examines the role of self-locking mechanisms in determining the mechanical response and energy absorption capacity of rigid origami metamaterials. Quasi-static compression tests were conducted on specimens exhibiting three distinct geometries (B19, B22, B23) and four wall thicknesses (0.8–2.0 mm). The results of these tests revealed two unique self-locking behaviors. Type I self-locking originates from inter-wall interlocking, characterized by progressively decreasing inter-wall spacing during compression; Type II self-locking originates from interlocking between creases, characterized by creases contacting each other during compression. The fabrication of the specimens was accomplished through the utilization of FDM-based additive manufacturing, employing PEEK material. The results obtained from this study revealed two distinct locking behaviors: It has been demonstrated that type I locking enables sustained deformation without load reduction. In contrast, type II locking has been shown to result in premature collapse and diminished energy absorption capacity. The B22 configuration has been demonstrated to trigger both locking mechanisms concurrently, thereby significantly enhancing performance metrics. This has been evidenced by improvements in both crush force efficiency (CFE) and specific energy absorption (SEA), whilst also delaying densification. In contrast, structures dominated by a single locking mechanism exhibit premature failure (B19) or inefficient energy absorption (B23). These findings emphasize the pivotal role of synchronized self-locking activation and geometric configuration in enhancing impact resistance and energy dissipation, thereby establishing a foundational theoretical framework for the design of advanced metamaterials in protective engineering.
Wu, Baoji, Wang, Hairui, Jiang, Heng
Extreme-Condition Analysis of Flow and Structural Strength in a Closed Space2026-99-12769/4/2026
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 Action2026-99-12759/4/2026
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 Impact2026-99-12869/4/2026
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
Research on Multi-Condition Topology Optimization of Transport Ship Pillar Structure2026-99-12289/4/2026
Structural optimization in shipbuilding represents a significant research focus within the fields of naval architecture and marine engineering. This study investigates multi-condition topological optimization for the deck pillar region of a transport ship's sectional structure. A mechanical model incorporating six typical load conditions was developed, and the Analytical Hierarchy Process (AHP) was employed to quantify the weighting coefficients for each condition. This enabled multi-condition collaborative topological optimization of the pillar layout. The optimized configuration underwent model reconstruction and finite element verification. Results demonstrate that the proposed multi-condition collaborative topology optimization method effectively balances structural performance and weight reduction requirements while satisfying strength specifications. This method yields optimal pillar layouts meeting multi-condition constraints, providing a reference for multi-condition topology optimization studies in ship structures.
Pei, Zihao, Wei, Yi, Feng, Ruge, Liu, Kun
An Energy Balanced Splitting Factor Calculation Method for Nonconforming Generalized Mixed Finite Elements with Distorted Meshes2026-99-12239/4/2026
This paper presents an Energy-Balanced Splitting Factor Method (EBSFM) for nonconforming generalized mixed finite elements to enhance accuracy and stability under mesh distortion. The splitting factor significantly influences the numerical solutions. Traditional approaches employ a uniform splitting factor for all elements, neglecting their distinct characteristics and boundary conditions. Wang's geometry-based Stiffness–Compliance Splitting Factor Method (SCSFM) is adopted to obtain element-wise initial values. Building upon SCSFM, the proposed EBSFM optimizes the splitting factor through an energy balance criterion that minimizes the deviation between mixed energy and generalized strain energy, thereby improving the physical consistency of the finite element model. The method establishes an approximate mapping relationship between unknown variables and splitting factors via matrix decomposition and reconstruction techniques, enabling element-wise adaptive optimization. The EBSFM demonstrates consistent superiority in terms of displacement accuracy, stress accuracy, and energy balance.
Shang, Zhongxin, Wang, Zhenyu
Validation Study of the Jaguar Land Rover Aerodynamic Computational Fluid Dynamics Process Using Metric-Based Assessment Criteria2026-01-50729/3/2026
Credibility of simulation data has always been fundamental in aerodynamic vehicle development, as a significant amount of early design phase work is conducted virtually before a physical test property is made. As the automotive industry pivots toward artificial intelligence and machine learning techniques to assist in aerodynamic development, training these models with simulation data requires a comprehensive understanding of the accuracy and validity of the underlying simulation. It is critical these systems are trained from reliable data with a full understanding of both the limitations and predictive performance of the computational fluid dynamics (CFD) process and the wind tunnel facility it is benchmarked against. Validation and verification studies have been a long-established set of guidelines to determine if the simulation model appropriately reflects reality (validation) or if it has been set with robust numerical schemes, mesh settings, or boundary conditions (verification). The work presented here shows a comprehensive validation study with more than 400 test configurations and 18 vehicle properties. It evaluates Reynolds-averaged Navier–Stokes (RANS) and detached eddy simulation (DES) approaches using moving reference frame (MRF) and rigid body motion (RBM) to account for wheel rotation and comparing STAR-CCM+ CFD process and the FKFS Aeroacoustic Wind Tunnel (AAWT). The results demonstrate that DES—particularly when wheel rotation is modeled using RBM—provides the highest overall predictive performance, with a drag accuracy from −2% to +4% for 80% of cases with corrections applied, which gets to ±2% for over 95% cases with an additional calibration step. A metric-based assessment criterion that combines key performance metrics into a single detection event (DE) score derived from failure mode effects analysis (FMEA) principles is proposed with an example shown for the 2021 Range Rover Velar. The benefit being that it removes a more judgement-based, qualitative approach, aiding toolset selection and methods development gaps.
Beves, Christopher, Simmonds, Nicholas, Dalmau Graells, Eric
Shimmy Dynamics Analysis of a Dual-Wheel Main Landing Gear Considering Side Stay Angular Coupling01-19-02-00078/31/2026
Main landing gear shimmy is jointly affected by tire forces, structural elasticity, damping, and geometric coupling. To investigate the influence of side stay angular coupling on shimmy stability, this article establishes a shimmy dynamic model of a dual-wheel main landing gear considering side stay angular coupling. Numerical continuation bifurcation analysis, Hopf bifurcation frequency mapping, and local sensitivity analysis are then employed to study its influence mechanism on stability boundaries, dominant modes, and multistable behavior. The results show that the horizontal inclination angle of the side stay introduces additional structural coupling between strut torsion and longitudinal bending, causing the longitudinal motion to evolve from a passive response into an important mode participating in shimmy instability. A small horizontal inclination angle can induce the coexistence of multiple stable periodic responses, whereas a larger inclination angle changes the connectivity of Hopf bifurcation curves and forms a new instability branch involving longitudinal motion. Further analysis indicates that adjusting the orientation angle to make the local horizontal inclination angle approach zero can weaken the direct structural coupling between torsion and longitudinal motion and reduce the sensitivity of the longitudinal response to variations in the horizontal inclination angle. These results indicate that the angular design of the side stay should comprehensively consider the coupling effect between the horizontal inclination angle and the orientation angle, so as to avoid multistability and mode transition induced by the side stay angular arrangement.
Wei, Jian, He, Jipeng, Zhang, Jiahao, Zhu, Shixing, Li, Shuangbao, Zhu, Hengjia
Influence of Restraint System Angles on Impact Response and Protection of Child Occupants in Vertical Crash Conditions2026-99-04138/28/2026
Focusing on the protection needs of child occupants in the scenario of aircraft vertical crashes, a finite element calculation model based on the cabin structure of a certain type of small electric aircraft was established. The child seat restraint system was coupled with the THUMS 3YO human body model, and the vertical 15 g condition meeting the requirements of Article 23.562 of CCAR-23-R3 was simulated. The influence law of the safety belt restraint angles (formed by different safety belt routing positions) on the dynamic response and injury indicators of child occupants was explored. To verify the rationality of the simulation results, a physical impact experiment was conducted using a Hybrid III 3YO child dummy and the same type of child seat, with key indicators (e.g., head acceleration, lumbar load) measured and compared with simulation data. The analysis results show that the effect of the safety belt restraint angle on the overall protective performance is less pronounced under vertical conditions, but a clear trend is observed: when the angle is in the range of 76°~84°, the head acceleration is relatively low and the brain tissue injury indicators are in the optimal state, which can effectively reduce the risk of head and neck injuries; when the restraint angle increases to 92°, the lumbar axial load and lung strain increase significantly, indicating a detrimental effect. The results of this study clarify the differences in the protective performance of child seats under different restraint angles, and provide a theoretical basis and technical guidance for the layout of safety belt anchors of aircraft seats and the optimal design of child seats.
Wang, Yafeng, Guo, Pan, Li, Weiliang, Shi, Xiaopeng
Lightweight Research on CFRP Bumper Impact Beam2026-99-04118/28/2026
As a critical component in vehicular passive safety systems, the automotive bumper beam significantly influences overall crash safety performance and lightweight potential. This study presents a comprehensive investigation into the lightweight design of a carbon fiber reinforced polymer (CFRP) bumper beam, systematically substituting a conventional aluminum alloy component based on the principle of equivalent bending stiffness. The research methodology integrates finite element modeling, design of experiments, and multi-objective decision-making to optimize crashworthiness. Initial design replaced the 3 mm aluminum beam with a 2.4 mm CFRP configuration using a [0°, 45°, 90°, -45°] ply sequence, demonstrating maintained structural integrity with substantial mass reduction potential. Through Latin Hypercube Sampling, 50 design configurations incorporating variations in panel thicknesses (five distinct sections) and ply orientation sequences were generated and evaluated under an 8 km/h frontal impact simulation. Crashworthiness was assessed through four key indicators: mass, specific energy absorption (SEA), maximum intrusion distance (Dm), and peak impact force (Fm). The entropy weight method objectively determined indicator weights, revealing maximum intrusion (49.27%) as the most critical factor, followed by mass (32.75%), peak force (9.75%), and SEA (8.23%). Subsequently, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was employed to comprehensively evaluate and rank all design alternatives. The optimized CFRP configuration (Scheme #38) achieved remarkable performance: 69.1% mass reduction (from 4.505 kg to 1.392 kg), 379.6% improvement in specific energy absorption, 12.6% reduction in peak impact force, while maintaining intrusion within acceptable design limits. This research establishes a robust framework for CFRP bumper beam optimization, successfully balancing lightweight objectives with enhanced crashworthiness, providing valuable insights for automotive lightweight safety component development.
Wang, Yizhi, Zhong, Rong, Long, Jiangqi
Dynamic Response and Energy Absorption of a Novel Arc-Shaped Hourglass Re-Entrant Honeycomb under Impact Loading2026-99-04178/28/2026
This study introduces an arc-shaped hourglass re-entrant auxetic honeycomb (AHRH) and examines its impact-induced dynamic response and energy-absorption behavior via finite-element simulations. The conventional re-entrant honeycomb (RH) is adopted as the baseline, and side-by-side simulations are performed at impact speeds of 10, 20, and 30 m/s. The mechanical response of both lattices is assessed through force-displacement characteristics, absorbed-energy histories, and representative deformation modes. Results indicate that the AHRH significantly reduces the initial peak force, prolongs the plateau stage, and exhibits a distinct dual-plateau feature, thereby achieving the desirable crashworthiness mode of “low initial peak-extended plateau-high densification”. Compared with the RH, the AHRH achieves increases of approximately 42.9%-59.7% in total energy absorption and 42.8%-56.1% in specific energy absorption while maintaining nearly identical mass. The enhanced performance arises from the arc-edge geometry, which alleviates local stress concentrations, promotes progressive buckling, and generates multiple plastic hinges. These mechanisms lead to smoother load transfer, avoidance of excessively high initial impact loads, and more efficient crash energy management. Overall, the proposed AHRH structure demonstrates superior energy absorption capacity and deformation stability compared with the conventional RH, providing new insights and practical references for the lightweight design and optimization of advanced protective and crashworthy structures.
Jiang, Zhide, Chen, Long, Yu, Ping
Finite Element Analysis of Mechanical Behavior of Steel Reinforced Concrete (SRC) Columns Designed by Different Methods2026-99-04158/28/2026
The design of integrated station-bridge structures is challenged by the coexistence of building codes based on Limit State Design (LSD) and railway codes using Allowable Stress Design (ASD). This study employs finite element analysis to compare the performance of Steel Reinforced Concrete (SRC) columns designed under these two philosophies. The results demonstrate the significant conservatism of the ASD method: When achieving the same safety margin, the ASD-designed column required 2.36 times the cross-sectional area, yielding an 89% higher axial capacity but a disproportionately small increase in shear strength, indicating material inefficiency. A subsequent parametric analysis identified steel strength as key to axial capacity and concrete strength as critical for shear capacity, with shear performance reaching its maximum at an axial compression ratio of 0.6. These findings quantify these behavioral differences, offering a basis for refining design methods and codes harmonization for such structural members.
Tang, Jia, Duan, Linli, Chen, Nan, Huang, Yunfei, Guo, Wei, Jiang, Lizhong, Yu, Yujie, Xu, Yongjia
Numerical and Experimental Investigation of the Impact of Close-Range Construction of Large-Section Tunnels on Existing Subway2026-99-04258/28/2026
Large-section tunnel construction using the mining method can significantly affect the operational safety of existing metro lines and ground stability, while their non-uniform settlement remains challenging to monitor comprehensively. In this study, the post-station section of a metro project in Chengdu was investigated to elucidate the vertical displacement and ground settlement behavior induced by a large-section tunnel undercrossing an existing metro line. A displacement reconstruction method integrating sparse-point monitoring with a radial basis function neural network (RBFNN) was developed to fit the full-field settlement distribution of both the existing line and the ground surface. A finite element model incorporating the existing shield tunnels, station structures, and the newly constructed mined tunnel was established, and the construction process was simulated. The numerical results indicated maximum settlements of 4.42 mm for the existing line and 4.37 mm for the ground surface, with fitting errors below 5.8% and 6.1%, respectively. Physical model tests further validated the approach, yielding maximum settlements of 0.86 mm and 1.01 mm for the existing line and ground surface, respectively, and an average fitting error below 3.5%. Both numerical and experimental findings confirmed that the induced displacements were within a controllable range and that the surrounding strata remained stable. The proposed method enables accurate and intuitive reconstruction of displacement distribution during under-crossing tunnel construction, reducing the number of required monitoring points while maintaining high fitting accuracy.
Wang, Rui, Chen, Jian, Cheng, Tao, Du, Lin, Li, Ruixiao
Simulation of Gas Diffusion in Nanoscale Microchannels at the Parallel Seam-Weld Interface2026-99-04198/28/2026
Driven by the stringent service conditions of aviation, aerospace, and military equipment, parallel seam welding, as an advanced resistance-welding packaging process, has been widely applied in ceramic-metal packages that require high hermeticity, owing to its excellent sealing performance and reliability. In this study, targeting the hermeticity failures that appear in parallel seam-welded ceramic packages after temperature cycling, molecular dynamics simulation is used to systematically investigate helium diffusion in nanoscale interfacial microchannels and its effect on hermeticity. On the LAMMPS platform, a three-region model is constructed that includes a helium-charging region, a wall-channel region composed of Fe, Ni, and Au, and a vacuum leak region. The Lennard-Jones potential is used to describe interatomic interactions, and a thermal-cycling environment conforming to MIL-STD-883, with a temperature range from -50°C to +125°C, is simulated to represent actual service conditions. The simulation results show that when the channel diameter is less than or equal to 1.2 nanometers, the number of leaked helium atoms remains constant at approximately 22 and is not affected by temperature; when the diameter is greater than or equal to 1.6 nanometers, the leakage exhibits significant temperature dependence. For example, in a 2.6-nanometer channel, 212 atoms leak at 423 K and 176 atoms at 223 K. Both leakage flux and leak rate increase markedly with channel size. OVITO analysis confirms that helium diffusion exhibits molecular-flow characteristics; at very small apertures, atomic escape efficiency is limited by the frequency of collisions with the wall. These findings provide insight for improving hermetic packaging and reliability of critical electronics used in aviation, aerospace, and military equipment.
Li, Xiangyang, Gong, Yubing, Zheng, Xianling
Finite Element Simulation and Application of Ultrasonic TOFD Detection for Austenitic Stainless Steel Welds2026-99-04068/28/2026
Ultrasonic TOFD detection is one of the most important non-destructive testing techniques for welds. However, the complex beam deflection, scattering, and attenuation of ultrasonic waves in the heterogeneous weld structure lead to the weak signal of the defect diffraction wave received by the probe and the low signal-to-noise ratio, which has a negative impact on the engineering application of ultrasonic TOFD detection technology in austenitic stainless steel welds. In this study, a numerical model of the ultrasonic TOFD detection process for austenitic stainless steel welds was established based on the finite element method. Combined with the test method, the interaction mechanism between the ultrasonic wave and weld structure is analyzed, and the probe arrangement method to reduce the interference of weld scattering noise is proposed. The results show that the finite element model can simulate the anisotropic characteristics of ultrasonic waves in austenitic stainless steel welds, including sound field distortion, sound energy scattering, and attenuation. Combined with the detection test, it has been proven that the adverse effect of the weld structure on the TOFD detection signal can be reduced by changing the probe detection surface.
Hu, Lichen, Huang, Hui, Qian, Shengjie, Hu, Weiwei, Chen, Zhenhua
Mechatronic Transfer Wheelchair Based on SLAM, A*/DWA Algorithms, and Finite Element Safety Assurance2026-99-03418/14/2026
With the acceleration of population aging, the number of disabled older people is increasing, and the demand for home care is also rising. In the case of a narrow space and no gap between the bed and the ground, the transfer of patients between the wheelchair and the bed has become a challenge. Current solutions suffer from bulky designs, require caregiver assistance, and pose potential safety risks. In order to solve the above problems, this paper proposes an intelligent transfer wheelchair with voice interaction and autonomous navigation function. The wheelchair innovatively adopts a cantilever transfer device, which can enable safe and stable transfer without requiring bed-floor clearance, and has the dual functions of a wheelchair and a transfer device, effectively saving family space. The stability of the structure is verified by finite element analysis. Under the action of a 500 N load, the maximum stress and maximum displacement are within the safety limit of the material. The wheelchair is also equipped with an advanced human-computer interaction system with voice interaction and autonomous navigation functions. Users can control the operation of the wheelchair through voice. The navigation module of SLAM and the hybrid A*/Dynamic Window Approach (DWA) path planner realizes the high-precision docking of the wheelchair and the bed. The results show that the design can realize the safe transfer of disabled people between wheelchair and bed, and provide a solution for home intelligent nursing.
Wang, Shunli, Peng, Li, Zhao, Liang
Stress Analysis and Simulation Study of Propane Spherical Tanks2026-99-03348/14/2026
As special pressure-bearing vessels, spherical tanks are widely used in chemical, oil refining, and other fields. However, their safe operation faces the dual challenges of structural failure and leakage diffusion. Meanwhile, due to its low lower explosive limit and the low ignition energy required, propane will evaporate rapidly after leakage to form an explosive mixed gas, which may further trigger severe accidents such as combustion and explosion. Therefore, this paper takes a 3000 m3 propane spherical tank as the research object, comprehensively applies the finite element analysis method, and systematically researches stress distribution, aiming to provide theoretical support for the safety design of spherical tanks and accident prevention and control.
Huang, Yuanxuan, Tao, Gang, Zhang, Lijing
Reliability Calculation and Analysis of Influencing Factors for Girth Welds in High-Grade Steel Pipelines Based on HMC-SS2026-99-03428/14/2026
Fracture failure of girth welds in high-grade steel pipelines poses a critical threat to pipeline integrity. Leveraging enhanced digitalization in pipeline engineering, a statistical database has been developed to support reliability analysis based on actual operational data. This study utilizes real project data to analyze the failure probability and key influencing factors of girth welds containing crack defects, thereby providing theoretical support for safety design and risk management. To overcome the conservatism of traditional deterministic methods, a probabilistic reliability model was established, incorporating a modified PRCI-CRES ultimate tensile strain criterion. Addressing the inefficiency of standard Monte Carlo (MC) simulation in high-dimensional low-probability contexts, an efficient Hamiltonian Monte Carlo-Subset Simulation (HMC-SS) strategy was introduced. Results show that HMC-SS improves computational efficiency by 99.95% over MC, with only 0.90% relative error. Key findings include: crack depth has the strongest influence – variation from 0.92 mm to 3.68 mm, which increases failure probability by 103 times; the strength matching coefficient is dominant, and higher values reduce failure risk; strain demand exhibits a positive correlation with failure probability and couples with material properties. It is concluded that high- or equal-strength material matching should be emphasized in welding, and reliability-informed design should account for multi-parameter interactions to ensure global safety.
Yang, Kai, Wang, Kaihong, Wang, Bin, Shao, Jia, Yu, Weichao, Zhang, Dong
Anti-splash System of Sprinkler Based on Millimeter Wave Radar and Machine Vision Fusion2026-99-03238/14/2026
In view of the problems that it is difficult to accurately control the spraying area of the mining sprinkler, and the resource waste caused by the mis-spraying material stacking area, as well as the failure of traditional radar monitoring in the complex electromagnetic environment, this paper proposes an anti-splashing system for the mining sprinkler. By combining millimeter wave radar and visual recognition fusion technology, the overall scheme of the anti-splash system is proposed. Then the control simulation of the whole system is carried out. The results show that the problem of poor control in traditional sprinkler operation can be effectively solved, and the sprinkler area can be adjusted intelligently. Finally, in order to verify the accuracy of the algorithm used in this paper, different algorithms are used for comparative experimental verification. The results show that the Modified YOLOv4 algorithm has a high accuracy of 98.75 %, which has good applicability and provides a theoretical basis for subsequent research.
Hou, Lin
Research on Rigidity-Intensity Analysis and Structural Optimization of the Shuttle Vehicle Load-Bearing Plate2026-99-03068/14/2026
The shuttle vehicle is a critical piece of handling equipment in automated logistics warehouses. As its primary load-bearing component, the load plate is subject to spatial constraints, requiring both a compact structure and effective prevention of structural deformation that could compress the battery. For a shuttle vehicle load plate developed by a company—with a rated load of 1500 kg and a maximum allowable deformation of ≤ 2 mm—this study first adopts the finite element method (FEM) to analyze its structural characteristics and establish a hybrid mesh model consisting of 1D beam elements, 2D shell elements, and 3D solid elements. Symmetry constraints are applied to reduce the computational scale. The structural deformation and stress under two constraint schemes (fixed constraints and surface-to-surface contact constraints) are compared and analyzed. The results indicate that surface-to-surface contact constraints should be adopted under this working condition, and potential design risks are identified. During the analysis, mesh independence is verified to determine an appropriate mesh size, thereby avoiding errors induced by mesh dimensions. Finally, an optimization design is conducted with the goal of lightweighting. Taking the cross-sectional dimensions of the load plate’s stiffeners and the thickness of the load plate as variables, and deformation as the constraint condition, the overall structural weight is reduced from 32.7 kg to 29.6 kg through multiple gradient-based iterative optimizations, effectively achieving the lightweighting objective. Experimental results show good consistency with the computational predictions. Additionally, the manufacturing process requirements and cost impacts of the optimized scheme are analyzed, and a manufacturing solution that meets technical requirements while ensuring economic feasibility is proposed.
Liu, Rui, Shen, Jie, Chen, Meng
Finite Element Analysis of New Energy Vehicle Chassis Using ANSYS2026-99-03438/14/2026
Amid the rapid development of the new energy vehicle industry, the vehicle frame, as the core load-bearing component of the entire vehicle, plays a direct role in the vehicle’s safety, lightweight design, and power performance through its design and performance. Although research on new energy vehicle frames has matured, issues related to the lightweighting of drive shaft-associated structures and the balance between weight reduction and strength/stiffness still require in-depth exploration. This study focuses on the chassis of new energy vehicles, utilizing Q295 low-alloy high-strength steel. Based on the vehicle’s dimensions and mass parameters, a simplified 3D model was constructed using SolidWorks. Static analysis under bending and torsion conditions, along with a 6th-order modal analysis, was conducted using ANSYS software. Based on the analysis results, optimizations were implemented at both structural and material levels: structurally, the central crossbeam was widened, holes were opened on the crossbeam’s vertical plane to reduce weight, and the longitudinal beam welding process was optimized; materially, Q295 steel was retained in high-stress zones, while aluminum alloy replaced it in low-stress zones. The optimized frame achieved a 15% reduction in torsional stress, a 16% decrease in bending stress, a 2% reduction in torsional deformation, and a 3% decrease in bending deformation. Total mass decreased by 12.7 kg, with both strength and stiffness meeting design requirements. This approach synergistically enhances frame lightweighting and performance, providing technical support for optimizing the overall performance of new energy vehicles.
Guo, Lihong, Wang, Yiyou, Yang, Zihao
Research on Wind-Induced Vibration Response of Heavy Cargo Ropeways for Power Transmission Lines2026-99-03308/14/2026
The construction of overhead power transmission lines in remote mountainous regions frequently relies on aerial ropeway systems, as conventional ground transportation is often impractical. However, complex terrain conditions combined with highly variable wind environments can significantly threaten the operational stability and structural safety of these cargo ropeway systems. To investigate these effects, a refined finite element model of a ropeway support was developed in ANSYS, and stochastic, time-varying wind fields were generated in MATLAB. The simulated wind time histories were applied to the numerical model to perform nonlinear transient dynamic analyses, enabling the evaluation of wind-induced displacement responses under different wind angles of attack. Based on the simulated response histories, critical stress- and displacement-sensitive regions of the support structure were identified, and the implications for structural detailing and design optimization of cargo ropeway supports were discussed.
Lv, Yanfeng, Yang, Zhonglv, Sun, Minggang, Jin, Hengdong
Design of Adaptive Overtorsion Sliding Mode Observer Based on Logarithmic Gain Law and Estimation of Satellite Disturbance Torque2026-99-03158/14/2026
The vigorous rate of new spacecraft being launched has made the accurate estimation of in-orbit environmental disturbances torques paramount to reducing attitude control performance corrosion. Leveraging telemetry from an asset in low-earth-orbit, we present a novel Adaptive Super-Twisting Sliding-Mode Observer, which interlinks three techniques heretofore decoupled: 1) saturation-constrained angular-acceleration adaptation; 2) Kalman-filter preconditioning of angular velocity; and 3) state-weighted logarithmic gain with dual leakage. Denoising of raw Euler angle sequences and detection of quasi-steady epochs are achieved with a customized Kalman update, while an adaptive band-pass stage isolates the torque-related acceleration signature. Casting these filtered data into the super-twisting form, we update the log gain on-the-fly, and twin leakage terms remove excess energy with accompanying chatter rejection—without compromising bandwidth. Head-to-head telemetry tests show a positive margin headroom on noise attenuation that has to be compared with the power-gain type counterpart and that increases with the signal roughness, thereby validating the fact that this technique refines environment torque estimates and hence strengthens robustness design envelopes in next-generation attitude-control systems.
Yin, Xu, Deng, Yuhui, Chi, Dongxiang
Design of a Four-Wheel Turning Tobacco Harvester Suitable for Hilly Areas2026-99-03338/14/2026
To address the core requirement of “layered ripeness and non-destructive harvesting” in tobacco-growing hilly regions of China, a specialized tobacco leaf harvester was developed. Considering the challenges posed by scattered plots and complex terrain, a four-wheel steering chassis system was proposed. The platform adopts a four-wheel independent drive and steering (4WID-4WIS) configuration, powered by DC servo motors and integrated with a microcontroller-based ROS system. The resulting drive chain—comprising motors, gear reducers, and off-road tires—achieves a maximum operating speed of 0.5 m/s. A novel rotary cross-blade harvesting module was designed in conjunction with a conveyor-based transmission mechanism, enabling stratified harvesting and leaf transport. Full-condition field tests were conducted. In terms of mobility, the harvester achieved stable operation at 0.5 m/s on cement roads, 0.1–0.2 m/s in fields, and demonstrated slip-free climbing on 20° slopes. In terms of harvesting performance, the system’s adjustable modules accommodated varying plant heights; however, issues with blade grip were observed when handling irregularly slanted stalks, affecting collection efficiency. During continuous field entry and exit operations, no mechanical failures occurred, verifying the prototype’s operational stability. This study introduces an innovative combination of omnidirectional mobile chassis and stratified blade modules, offering technical support for the modernization of tobacco agriculture. Further refinement of the harvesting strategy will be pursued to enhance practicality.
Guo, Ting, Gu, Jin, Li, Wen, Tang, Xiaoming, Long, Chao, Yang, Dongchao
Failure Analysis of the Safety Valve Spring in a Dangerous Goods Tanker2026-99-03138/14/2026
During the operation, a spring in the built-in safety valve of a dangerous goods tanker. A comprehensive failure analysis of the material was conducted through macroscopic and microscopic inspections, metallographic analysis, energy spectrum analysis (EDS), and hardness tests. The failure mode of the broken spring was brittle fracture. The fracture morphology was like that of ice sugar, and the chemical composition of the spring steel met the specified requirements. The main cause of fracture failure is the mechanical damage to the inner surface during the spring manufacturing process, which leads to stress concentration in the damaged area and ultimately results in fracture. In addition, manufacturers should strengthen and standardize the production process to prevent mechanical damage and select high-purity spring steel to improve the durability of the springs.
Yang, Lijun, Li, Qingshan, Xiong, Mingming, Liu, Mingming, Wu, Junyao, Yu, Lang, Zhang, Zewei, Xie, Xumeng
Analysis of the Influence of the Centroid Distribution of the Raft on the Shafting Alignment2026-99-03048/14/2026
Aiming at the problem of shaft alignment disturbed by the centroid distribution of the raft in the ship propulsion system, the quantitative influence of centroid offset on bearing load distribution and axis deformation is revealed. Based on the theory of an elastically supported continuous beam, the finite element model of the raft-shaft coupling system is established. By adjusting the position of the raft counterweight mass point (longitudinal offset range ±0.5 m) to simulate the centroid change, the static solution algorithm is used to analyze the key parameters, such as bearing load and axis alignment accuracy, under multiple groups of centroid offset conditions. It is concluded that when the centroid of the raft moves to the propeller end, the load of the 1# and 2# bearing near the propeller end increases, and the load of the 3# and 6# bearing near the thrust plate end decreases. The lateral offset of the center of mass increases, the axial offset at the stern bearing increases, the maximum deflection of the shafting increases, and the deformation of the raft structure increases. The centroid distribution of the raft is a disturbance source of the shafting alignment state, and its offset will reconstruct the bearing load distribution and cause the axis deformation. It is recommended to control the lateral offset of the center of mass at the design stage and reserve the dynamic compensation margin for the shafting alignment.
Yin, Hong, Jin, Yong, Wang, Jun, Tian, Jiabing
Structural Design and Mechanical Performance Analysis of Key Components of Deicing Robots for Transmission Lines2026-99-03468/14/2026
Extreme winter weather often leads to ice accretion on transmission lines. Manual removal is inefficient, costly, and poses safety risks. To address this issue, this paper presents the design of a de-icing robot to replace manual operations for transmission line de-icing. The main content focuses on the detailed structural design of the robot, including the mobile platform, de-icing mechanism, and adaptive adjustment module. Finite element simulations are conducted on key components to verify the structural rationality and the correctness of material selection. The proposed de-icing robot enhances the safety of the de-icing process, improves operational efficiency, and provides a valuable reference for transmission line de-icing methods, demonstrating significant practical value.
Chang, Hao, Zhen, Chen, Han, Fengmei, Li, Cheng
Strength and Rotor Dynamic Simulation Analysis of a Brake Testing Device2026-99-03278/14/2026
The brake test bench is an effective method for studying wheel-rail interaction by simulating the braking process of rail vehicles. To ensure the safe and reliable operation of the brake test bench, this article focuses on introducing a comprehensive single-wheel brake test device. A finite element model of the wheelset assembly and test bench was established, and the strength, mode, and dynamic performance of the wheelset assembly and braking system were analyzed by simulating the braking process. The analysis results indicate that the wheelset assembly and braking system meet the strength requirements of the braking test process, and the test speed is maintained below the critical speed of the test bench. This validates the rationality and safety of the brake testing device and provides a foundation for subsequent brake research.
Jing, Yuhang, He, Taixiong, Song, Ye
Dynamic Response Analysis of RV Reducers with Time-Varying Stiffness2026-99-09088/7/2026
As a high-precision transmission core component, the RV reducer’s performance depends on the time-varying stiffness of its core components. Building a time-varying stiffness model is essential for studying its dynamic characteristics. This paper addresses the lack of key factors in existing dynamic studies by creating a multi-factor coupled dynamic model. It analyzes the time-varying stiffness of the crankshaft bearing, involute gear, and cycloid gear-pin gear. The study also focuses on building a dynamic analysis model for the crankshaft bearing. By measuring changes in oil film thickness and initial assembly clearance caused by temperature rise, it explains how combined clearance affects bearing performance. To verify the model, a domestic RV reducer is modeled and assembled in SolidWorks. The simplified model is imported into ADAMS for simulation. Under set load and speed conditions, dynamic parameters like angular velocity and acceleration of core components are obtained. This provides a more scientific analysis method and data support for understanding the dynamic characteristics and improving the transmission performance of RV reducers.
Xuan, Liang, Teng, Shaowei, Huang, Ruizhe, Wan, Zefu, Shao, Mengqi, Yu, Zhishen, Wang, Ziyue
Research on the Cumulative Damage Mechanism of Special Equipment Steel Structures Based on Complex Load2026-99-10118/7/2026
Steel structures subjected to complex loading conditions undergo various types of damage, including fatigue, crack propagation, plastic deformation, and corrosion. As time and loads accumulate, these damages may lead to structural failure. The investigation of the damage mechanisms and constitutive models for special equipment steel structures under complex loading has been a significant challenge in engineering. This study develops a constitutive model for steel structure damage under static and dynamic loads, as well as vibration disturbances, through a normalization approach. The proposed model is validated via simulation to assess its feasibility. The findings offer a theoretical foundation for the design, life prediction, and health monitoring of steel structures in special equipment, aiming to enhance their safety and reliability. This research provides critical insights into damage analysis, failure prediction, and the optimization of repair strategies for steel structures, with significant practical implications in engineering applications.
Wang, Jun, Yu, Zhen, Huang, Yong-qiang, Chen, Wei-bi
Research on Corrosion and Friction Behaviors of 8Cr4Mo4V Bearing Steels in Corrosive Medium Environments2026-99-10068/7/2026
Corrosion-wear damage behavior affects the bearing life and reliability seriously in a corrosive environment. The accurate evaluation of the tribocorrosion behavior of 8Cr4Mo4V bearing steel samples is critical for the application and protection of bearings. The present work seeks to establish the relationship between laboratory salt spray accelerated experiments and the corrosion of 8Cr4Mo4V steel samples in real outdoor marine atmosphere exposure, and investigate the tribological behavior in the corrosion-wear process under artificial seawater. Results show that salt spray corrosion tests can well simulate the corrosion of 8Cr4Mo4V steels in marine atmospheric exposure. The tribocorrosion performance of 8Cr4Mo4V steels under artificial seawater conditions is affected by the temperature effect of the corrosive liquid and the working conditions. Increased normal load and reduced rotational speed can improve the anti-friction performance. This work offers the possibility and reference of precise control of corrosion-wear-coupled damage failures for bearings.
Zhao, Chao, Ying, Lixia, Nie, Chongyang, Zhu, Tianlin, Sun, Dong
Study on Visible-Light-Driven Photocatalytic Degradation of Tetracycline Hydrochloride by g-C 3 N 4 /CoFe 2 O 4 Composite Photocatalysts2026-99-10078/7/2026
g-C₃N₄, a metal-free semiconductor photocatalyst, demonstrates remarkable potential, but its practical application in pollutant degradation is significantly limited by the rapid recombination of photogenerated electron-hole pairs and low photocatalytic efficiency. To address this, a series of magnetic recyclable g-C₃N₄/CoFe₂O₄ composite photocatalysts with different CoFe₂O₄ doping ratios were innovatively designed and prepared via thermal polymerization, sol- gel, and combined with ultrasonic and heat treatment processes. The novelty of this composite design lies in the effective integration of magnetic CoFe₂O₄ with g-C₃N₄ through a heterojunction structure. It substantially boosts the absorption of visible light. Concurrently, it effectively fosters the separation and mobility of photo-induced charge carriers. The composite materials were systematically characterized by X-ray diffraction, thermogravimetric analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy, photoluminescence spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy. Using tetracycline hydrochloride as the target pollutant, the photocatalytic activity of the composites was evaluated under visible light irradiation, and the effects of initial concentration, catalyst dosage, and the influence of solution pH on degradation efficiency were also examined. The results indicated that the composite with a CoFe₂O₄ to g-C₃N₄ mass ratio of 1:3 (denoted as 3-CN/CFO) exhibited the optimal performance: a TCH degradation rate of 80.29 % within 105 minutes and a total organic carbon removal rate of 61.63 %. After five consecutive cycling experiments, the degradation efficiency remained above 70 %, demonstrating good reusability and stability. The performance improvement is attributed to the formation of heterojunctions in the composite, which effectively facilitates charge separation, inhibits carrier recombination, and enhances visible light absorption. Furthermore, the inherent magnetism of the composite permits efficient recovery, streamlining its integration into practical applications. Toward the purification of antibiotic-contaminated water, this research proposes a viable method for fabricating highly effective and recyclable photocatalysts.
Hua, Longjun, Chai, Tian, Wang, Yiming, Zhang, Jing, He, Ting
Structural Optimization Design and Experimental Study of a Shipboard Cabinet2026-99-09018/7/2026
The shipboard cabinet is an important carrier of radar equipment. It is necessary to ensure a good working environment and provide maximum support and protection for the internal equipment. In this paper, a shipboard cabinet that can realize a parallel heat dissipation architecture was taken as the object. The natural frequency and mode were used to find the area where the cabinet was prone to high-frequency vibration under impact excitation. The response characteristics of the cabinet under strong impact conditions were studied using a nonlinear transient dynamic analysis method. The weak links in the cabinet structure were identified, and the structural reinforcement design was carried out. After optimization, the maximum stress value of the cabinet was significantly reduced, and the safety factor was greater than 1.5. Finally, the effectiveness of the structural optimization was verified through experiments. The cabinet vibration isolation system was optimized and selected to ensure that it has good vibration isolation characteristics and impact response. The vibration isolation performance of the wire mesh isolator and the non-resonant peak isolator in the shipboard vibration and impact environment was verified by experiments. The impact transmissibility is less than 0.3, and the vibration transmissibility is less than 1.5, which can further improve the vibration and impact resistance of the shipboard cabinet.
Ni, Xiaokang, Jiang, Bo, Zhang, Liangjuan, Wu, Jingkai
Research on the Operating Characteristics of a Micro Turbine-Based Emergency Device2026-99-09128/7/2026
To meet the power and electricity supply demands in special scenarios such as fire safety rescue, mine refuge chambers, and explosion-proof and dust-proof environments, a portable emergency rescue device powered by compressed air and driven by a two-stage axial-flow micro-pneumatic turbine is proposed. The pressure and velocity fields of the pneumatic turbine were analyzed using a combination of numerical analysis and experiments. The effects of nozzle number and inlet pressure on the operational characteristics of the turbine and the emergency device were compared. The results show that the maximum ratio of the output torque of rotor 2 to rotor 1 is 12%. The output power of rotor 2 is less than that of rotor 1, with the maximum output power of rotor 2 being 16.5% of rotor 1. The two-stage rotor structure helps to reduce residual speed loss. At the same rotational speed, increasing the inlet pressure of the turbine can enhance its output power. At an inlet pressure of 300 kPa and a rotational speed of 30, 000 rpm, the aerodynamic turbine torque is 13.8 N·m, and the turbine reaches an output power of 42 W. The emergency device, operating in a triple-nozzle mode, shows higher power and efficiency compared to the two-nozzle mode, demonstrating a higher power and efficiency than that observed in a two-nozzle mode. The maximum power output is 28.1 W, with the highest efficiency reaching 24.87%.
Liu, Jiang, Wu, Xi, Gao, Zhiwei, Chen, Bin, Ma, Renjun
Items per page:
1 – 50 of 10592