Browse Topic: Design processes

Items (4,881)
To meet the demands of on-orbit monitoring and space situational awareness, this study proposes a Transformer-based relative motion pattern recognition method based on the self-attention mechanism, addressing the issues of difficulty in accurately characterizing the relative motion patterns of non-cooperative space targets under short-arc observation conditions, strong dependence on prior knowledge in traditional methods, and insufficient stability under noise interference. Firstly, this study constructes a non-cooperative spacecraft motion pattern action data set based on the Clohessy–Wiltshire (C-W) relative motion equation. By designing typical initial conditions of relative motion, trajectory samples including fixed-point following, hovering following, oscillating following, coplanar circling, non-coplanar circling, approaching and receding, etc. of multiple motion patterns are generated, and the relative position and relative velocity sequences in the local orbital coordinate system are used as model inputs. Subsequently, an motion pattern recognition network composed of an input representation module, a Transformer encoding module, and a classification output module is constructed. The trajectory sequence representation is achieved through linear embedding and position encoding, and the multi-head self-attention mechanism is used to capture the global dependencies and key dynamic features between different time steps, thereby completing the discrimination of the target motion pattern category. Finally, model training and testing are carried out based on the constructed data set, and experimental analysis is conducted from three aspects: training convergence, classification performance in the absence of noise, and robustness in the presence of noisy observations. The results show that the proposed method can effectively learn the discriminative features in short arc segment relative motion, and performs well in terms of accuracy, Macro-F1, and confusion matrix; in the presence of Gaussian noise interference, it outperforms the Multi-Layer Perceptron (MLP) baseline model while still maintaining clear category boundaries and high recognition stability.
Mao, Yicheng, Zhang, Zexu, Li, Yingshuo, Song, Zhuo, Zhang, Fan, Liang, Jintang
Space membrane structures, prized for their lightness, affordability, and ability to fold and unfold, hold immense promise for missions like deep space exploration, high-definition Earth observation, and advanced satellite communications. However, these structures are typically large-size, ultra-lightweight, highly flexible, and have very low damping. This leads to complex dynamic behavior featuring significant geometric nonlinearity, strong coupling between rigid and flexible motions, and uncertain parameters. Consequently, creating accurate yet simple mathematical models for designing controllers is exceptionally difficult, and traditional control methods that rely on such models often fall short. To tackle this problem, this study focuses on a membrane antenna spacecraft equipped with cable actuators, aiming to suppress its vibrations during attitude maneuvers. Using the Deep Deterministic Policy Gradient (DDPG) algorithm, an intelligent vibration controller based on the Actor-Critic architecture is designed. This approach is data-driven, meaning it learns effective control strategies directly through interaction with the system’s environment, bypassing the need for a precise pre-defined mathematical model. Simulation results show that the controller demonstrated superior vibration suppression and strong adaptability across several key scenarios.
Zhang, Hua, Chen, Cheng, Liu, Xiang
The Army’s transformation mandate is unambiguous: deliver warfighting capability 25–30% faster. Every Tier 2 metric published in support of that mandate – days between milestones, days to complete the requirements process, days to complete contracting, days to complete testing – is really a decision throughput measurement. Yet the systems engineering (SE) discipline that governs those timelines has no formal production framework for producing decisions. This paper proposes Decision Engineering as the framework. Grounded in lean production theory, applied to information work and anchored to the defense acquisition policy structure of DoDD 5000.01 and DoDI 5000.02, Decision Engineering reconceives SE as the discipline of designing, operating, and continuously improving the lifecycle decision production system. It introduces a formal decision ontology comprising six decision states (Latent, Declared, Active, Deferred, Closed, Reopened), four topology relationship types (Precedes, Enables, Constrains, Triggers), and five diagnostic biomarkers that measure production system health. The paper presents the Decision Factory model and describes how its application to ground vehicle system programs and across the Army acquisition enterprise can accelerate capability delivery without sacrificing rigor. Defense acquisition programs do not fail for lack of engineering rigor or digital tooling. They fail because the production system that converts information into decisions is ungoverned – no inventory count, no flow discipline, no throughput measurement. Decision Engineering names this production system, provides instruments to measure its health, and offers a practitioner framework for running it better.
Alexander, Eric, Foglesong, Matthew, Berklich, Louis (Bill)
This paper introduces a method of predicting system robustness using engineering models with aleatory uncertainty. The Stochastic Robustness Evaluation and Categorization (SREC) method is useful for the design of systems where performance along some dimension is limited by several failure modes. SREC integrates and extends interaction plots and Monte Carlo methods to complex engineering models. These complex models are often difficult to evaluate and visualize due to the curse of dimensionality. SREC is effective for non-linear, non-convex, non-monotonic, and discontinuous models due to its basis in Monte Carlo methods. The method is based on the identification of low-performing solutions, the construction of probability density functions and intervals from these solutions, and the categorization of the input space based on the likelihood of low-performing solutions occurring. Using SREC in the late stages of the design process provides insight to the designer about possible improvements in the system’s robustness. A ground vehicle model based on a US Army test procedure is used to demonstrate the effectiveness of SREC on high-dimensional, multi-failure mode models.
Louis, Edward, Mocko, Gregory, Taylor, Evan
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
Verification of functional requirements in Model-Based Systems Engineering environments remains fragmented across heterogeneous tools and manual processes. This paper presents a digital twin–enabled workflow that supports automated requirement verification through integration of SysML models, executable simulation environments, and verification evaluation functions. Within this scope, the objective is to formalize a verification workflow that preserves architectural abstraction while enabling automated, traceable, and simulation-driven evaluation of functional requirements. The approach establishes a continuous digital thread that maintains traceability between requirements, system architecture, and verification outcomes. The workflow is demonstrated using a differential-drive robotic platform, where sensor data availability and update rate verification are used as representative examples of digital twin-based functional requirement evaluation. Results illustrate the feasibility of incorporating digital twin-driven verification into model-centric engineering processes while maintaining consistent verification feedback within the system model. The demonstration produced both passing and failing verification outcomes, illustrating the workflow’s ability to surface requirement-design mismatches.
Zeki, Omar, Sahebsara, Farid, Torkjazi, Mohammadreza, Hieb, Michael R., Raz, Ali K.
This paper presents a CFD-based optimization workflow for the simulation and development of automotive cooling circuits, integrating three-dimensional steady-state analyses with one-dimensional transient modeling. The objective of the activity is to establish a robust methodology that links detailed component-level thermal characterization to system-level dynamic simulations, enabling the assessment of cooling performance under both driving and charging operating conditions. The thermal behavior of the cooling circuit components was first investigated using three-dimensional steady-state simulations performed with Ansys Fluent. For each relevant operating point, the fluid flow and heat transfer were resolved in full 3D, and temperatures were monitored at multiple locations within the components and along the circuit. The steady-state analyses provided spatially resolved temperature fields and heat transfer characteristics for a range of boundary conditions representative of real operating scenarios. From these results, temperature and performance maps were generated, describing the relationship between operating conditions, heat loads, and thermal responses of the components. These maps were then used for the calibration of one-dimensional models implemented in GT-Suite. The calibrated 1D models reproduce the thermal behavior observed in the 3D CFD simulations while allowing efficient simulation of the entire cooling system under transient conditions. This multi-level approach enables the combination of detailed local physics from CFD with the computational efficiency required for system-level dynamic analyses. Transient simulations were carried out in GT-Suite to evaluate the thermal response of the cooling circuit during both driving and charging phases. The driving phase accounts for variable thermal loads and flow conditions associated with vehicle operation, while the charging phase represents operating conditions specific to battery recharging scenarios. The calibrated 1D models were used to simulate the evolution of temperatures throughout the system over time, considering the interactions between components and the overall thermal inertia of the circuit. The results show that the designed cooling system is capable of maintaining component temperatures within the targeted limits across the analyzed operating conditions. The thermal containment is achieved for all components included in the cooling circuit under both dynamic driving and charging scenarios. The electric motor is oil-cooled and therefore is not part of the water-based cooling circuit addressed in this study. The proposed CFD-to-1D workflow provides a consistent and transferable methodology for the thermal development of cooling systems of high power density electrified powertrains. The novel contribution lies in (i) the application of the multi-level framework to a heavy-duty platform with SiC-based power modules and dedicated on-board charger developed within the Horizon Europe POWERDRIVE project, (ii) a DOE-based map generation strategy that preserves the conjugate heat transfer interactions between actively cooled components (power modules, OBC) and passively cooled neighbors (busbar, capacitors) within the reduced-order representation, and (iii) the integration of the reduced-order maps within a single transient system-level model covering both vehicle-at-rest charging and dynamic driving operating modes. This activity is carried out within the framework of the Horizon Europe project POWERDRIVE.
Chiappini, Daniele, Tribioli, Laura, Rodionov, Artem
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
This study conducted a comprehensive economic evaluation of two major HEV architectures: the series-parallel configuration and the range-extended configuration. An analysis of these two configurations was performed using integrated vehicle and control models, allowing for a direct comparison of energy efficiency and operational economy. Findings show that the range-extended configuration has clear advantages in structural complexity, simplicity of control strategy, and development cost, while its energy consumption performance is similar to that of the series-parallel configuration. The results challenge the long-standing notion that range-extended configuration is less efficient, offering a new perspective on the design and configuration choices for hybrid electric vehicles.
Li, Ping, Guo, Wencui, Nie, Guole, Niu, Yazhuo, Bai, Bateer
Point cloud registration represents a fundamental task in geospatial informatics and 3D computer vision, aiming to align heterogeneous point clouds through rigid transformation estimation. While Super-4PCS serves as an efficient coarse registration method, it exhibits limitations when handling large-scale datasets, planar-distributed point clouds, and scenarios with unknown scale differences. To overcome these challenges, this paper proposes the Nc-5PCS (Neighborhood-constrained 5-Point Congruent Sets) algorithm. Nc-5PCS first performs approximate scale estimation through concavity-convexity similarity analysis within coarse overlap regions, addressing the inherent scale limitation in 4PCS-based approaches. Subsequently, the algorithm employs 3D Harris feature point extraction to significantly reduce data volume while preserving critical geometric characteristics. The core innovation lies in designing a non-coplanar 5-point basis with a corresponding hash-based retrieval mechanism, effectively resolving the feature degradation problem caused by coplanar 4-point bases. Furthermore, normal vector angular constraints are incorporated to enhance consensus evaluation during correspondence selection, substantially improving registration accuracy. Experimental validation demonstrates that Nc-5PCS achieves a point-to-point RMS error of ≤ 0.227 m, outperforming Super-4PCS to provide superior initial alignment for subsequent ICP refinement.
Liu, Lei, Yu, Keguang, Li, Xinyi, Sun, Guangde, Zhao, Xinyuan, Zhu, Dongni, Fan, Yabo, Guo, Shihao
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
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
The modeling accuracy of the air rudder system directly affects the quality of aircraft attitude control. However, the commonly used simplified second-order model cannot accurately represent its nonlinear transfer characteristics. To this end, a dynamic model of the air rudder system considering three types of nonlinear factors, such as saturation, clearance, and dry friction, was established. On this basis, a stepwise identification test modeling method based on frequency characteristic data was proposed. By designing two different excitation levels of test conditions to excite or suppress the influence of some nonlinear factors, the stepwise identification of each unknown physical parameter was completed. The identification results show that the air rudder system model established in this paper can accurately characterize its nonlinear transfer characteristics, and the transfer characteristic curve of the identification results is in good agreement with the measured data.
Wang, Ding, Nangong, Zi-jun, Liu, Bo
The case for advanced powder coatings. Corrosion in automotive components is often framed as a cost problem, but for design and manufacturing engineers it is more accurately understood as a system-level failure mechanism. Nowhere is this more visible than in wheel assemblies, where environmental exposure, mechanical damage, and coating performance intersect. For wheel manufacturers, corrosion is not simply a maintenance concern; it is a function of material selection, geometry, surface preparation, and coating system design, all interacting under real-world conditions. The global cost of corrosion is frequently cited in trillions of dollars annually. Estimates from the Association for Materials Protection and Performance (AMPP) place this figure at over $3 trillion, with up to 35% considered preventable through improved design, material selection, and protective strategies. For engineers, the more relevant point is that a significant proportion of corrosion-related failure can be addressed through earlier-stage decisions. In practice, this means designing components and processes that limit the initiation and propagation of corrosion, rather than relying on coatings as a final barrier alone.
Carvalho, Gustavo
MIT students designed, built, and tested a jet engine with AI copilots, assessing AI's usefulness in developing high-performance aerospace systems. Massachusetts Institute of Technology, Cambridge, MA Artificial intelligence has rapidly transformed software engineering. But when the task is to conceive, design, and make a complex physical system such as a jet engine, are those AI tools equally transformative? The Jet-engine AI Research and Validation Intensive Sprint (JARVIS) Challenge set out to explore that question by asking MIT undergraduates to discover whether AI can help them build faster and better. Rather than treating AI as a writing assistant or coding accelerator, the challenge put it into a safety-critical hardware environment where every calculation, material choice, machining delay, and assembly tolerance mattered.
Engineers designing pivot points for outdoor and heavy-duty equipment have long accepted the familiar routine: grease it, run it, regrease it and repeat. This approach may work well enough. But as equipment pushes into harsher environments and tighter service windows, “well enough” is no longer the standard. Maintenance-free pivots - pivots that run dry, resist corrosion and hold their tolerances through seasons of hard use - offer an increasingly compelling alternative. Designing one requires rethinking what a pivot point actually is, with most engineers focusing only on the bearing itself. While this instinct is understandable, it's also incomplete. A pivot consists of a bearing, shaft and housing working together, requiring a systems-level approach. Optimize only one element and you may still end up with a failure.
Prokopec, John
I wanted to return to the topic from last month's column, my visit to the annual Summit of the International Transport Forum, the world's largest gathering of transport ministers and a global transport policy event, in Leipzig, Germany. Since there wasn't a lot of news directly related to automotive engineering news, I wanted to share a bit from this high-level event through editorial privilege. It was interesting to hear from some of the people in charge around the world as they shared their views on our current transportation situation and what they are doing to affect the future. At a panel on EV expansion, for example, the people in the room seemed to agree that the commercial EV industry has moved beyond proving the viability of battery-electric trucks and is shifting focus to overcoming infrastructure, regulatory, and systems integration challenges that continue to limit large-scale deployment. Even better, for those of us who've been listening to the arguments for and against electric vehicles for multiple decades now, representatives from across the industry - including logistics providers, vehicle manufacturers, charging companies, and policy groups - said that zero-emission freight transport has become a business strategy today, more so than any sort of sustainability effort as it might have been in years past. In the same vein, what might have been a battery-electric transport pilot program in 2016 can today be integrated into an organization's core freight operations.
Blanco, Sebastian
Ultrasonic guided waves enable long-range, low-intrusion inspection of pipelines. This study examines how array topology and axial spacing influence the quality of defect echoes when the longitudinal axisymmetric mode L(0,2) is used. We build COMSOL finite-element models of a steel pipe and excite it with PZT-4 at 80 kHz; three practical layouts are compared: (i) odd–even receiving, (ii) 8-transmit/8-receive, and (iii) 16-transmit/8-receive, arranged as two axially separated groups. The spacing between the groups is chosen to suppress parasitic modes such as L(0,1) and to strengthen L(0,2). Results show that the two-group configuration sharpens the defect echo and reduces modal interference; increasing the number of transmitters further raises the defect-wave amplitude and improves the separation from end-reflection echoes. Among the schemes, 8×8 performs well for small-defect identification, while 16×8 yields the clearest boundaries and fastest defect indication. These findings clarify how sensor number and placement govern modal purity and sensitivity, and they offer practical guidance for designing guided-wave arrays that improve the reliability of long-range pipeline inspection. - Ultrasonic guided waves Pipeline non-destructive testing L(0,2) mode; Sensor array layout; Finite element simulation; Guided wave signal processing.
Liao, Wei, Li, Tengfei, Zhang, Wenhui, Lin, Qingming, Guo, Yanbing
To fulfill the multi-tube launch requirements for a specific folding-wing UAV, this study improves the structure of the existing storage-launch container. Based on the finite element method, a parametric model of the container is established, and a multi-condition mechanical analysis is carried out for various storage, transportation, and launch conditions. The difference between the first six natural frequencies of the free mode and the prestressed mode is compared and analyzed. The modal analysis model considering prestress is used to identify the optimization area of the container. The variable density method (SIMP) is used to optimize the topology of the container, with the volume of the container as the constraint condition and the minimum strain energy as the optimization goal. The optimization results show that the first-order modal natural frequency of the container is increased by 108%, and the first six natural frequencies are increased to a safe range, which effectively avoids the resonance risk. At the same time, the quality is reduced by 29%, and good optimization results are achieved.
Yuan, Weiyang, Ji, Yuguo, Liu, Zhipeng, Yu, Wenxin
The rapid evolution of electric vehicles (EVs) has led to the development of innovative approaches to optimize ride comfort, handling, and the overall suspension performance. EVs introduce unique challenges due to their distinct weight distribution, powertrain dynamics, and noise characteristics, unlike their conventional internal combustion engine (ICE) counterparts. This paper outlines an advanced damping force modeling methodology using machine learning (ML) techniques to enhance the suspension design process for next-generation EVs. The analysis is based on data-driven ML algorithms, i.e., Gradient Boosting, Random Forest, and Neural Networks, to simulate the nonlinear and frequency-dependent phenomenon of dampers in different operating conditions. A comprehensive dataset, generated through simulation and experimental testing, captures the effects of road profiles, vehicle dynamics, and damping settings. Additionally, this research evaluates the impact of machine-learned damping force predictions on critical ride and handling metrics, including ride comfort, road-holding ability, and energy efficiency. The results demonstrate that the ML models can enhance the iterative design process considerably and help to create the adaptive suspension systems that will address the particular requirements of EVs. This paper contributes to advancing the state-of-the-art of the suspension modeling, incorporating the ML-based insights in the development cycle. It highlights the possibility of artificial intelligence to transform suspension design, paving the way for superior ride quality and vehicle performance in electric mobility.
Hazra, Sandip, Tangadpalliwar, Sonali, Khan, Arkadip
With the advance of high-end manufacturing and the rise of green design, lightweight structures have become a central concern in aerospace. Topology optimization offers a principled route to shed mass while preserving performance, yet most additive manufacturing (AM) studies still emphasize process tuning and new materials rather than structural layouts constrained by AM realities. This work targets a representative wing rib from a specific unmanned aerial vehicle (UAV) and formulates a multi-objective topology optimization that explicitly embeds AM constraints. Using the Solid Isotropic Material with Penalization (SIMP) variable-density framework, we couple static stiffness and strength measures with modal objectives so that the optimized rib not only resists deformation and limits stress but also improves the first three natural frequencies, thereby mitigating adverse vibration interactions at the wing level. A compromise-programming strategy balances these competing objectives under volume and manufacturability requirements, including AM-driven minimum feature scales and related geometric restrictions. Finite-element analyses are used throughout the loop to evaluate displacement, von Mises stress, and eigenfrequencies, ensuring that the emerging material distribution is both efficient and physically meaningful. The resulting topology exhibits clearer load paths and smoother stress flow, reduces peak displacements, and delivers a marked rise in the first three natural frequencies. Overall mass is lowered by approximately 55% while meeting all imposed constraints, achieving the dual aims of structural optimization and lightweighting. The study demonstrates that integrating AM constraints directly into the optimization stage yields designs that are performance-robust and fabrication-ready, and it provides a reusable workflow for thin-walled aerospace components such as wing ribs where stiffness, strength, and vibration behavior must be jointly considered.
Zhao, Fei, Zhang, Heran, Li, Xiaoting, Shi, Bowen, Kong, Xiangwei
To optimize fluid forces on the multi-way valve blades within thermal management systems of new energy vehicles, this study employs a systematic design methodology integrating parametric modeling, surrogate modeling, and multi-objective optimization. Using the Tesla Model Y 8-way valve as a case study, a parametric model is established. A high-fidelity sample dataset is generated through computational fluid dynamics (CFD) simulations utilizing optimal Latin hypercube sampling (OLHS). A radial basis function-thin plate spline (RBF-TPS) surrogate model is subsequently developed to replace computationally expensive CFD analyses. Global sensitivity analysis is performed using an improved Sobol’s method. Structural optimization of the valve core blades is then conducted via the NSGA-II genetic algorithm. Results indicate that valve core structural parameters significantly influence the fluid force on individual blades, with inner diameter, outer diameter, and blade thickness exhibiting the greatest impact. Multi-objective optimization achieves a substantial reduction in the fluid force acting on each blade. Simulation verification confirms the optimization outcomes with minor discrepancies.
Liu, Jiaming, Sun, Xiaoxia, He, Xiwang, Du, Changqing, Song, Xueguan, Shen, Lili
Focusing on the requirements engineering activities, this study analyzed the problems in the implementation process of the forward design practice of commercial aircraft airframe, introduced the breakthrough methods, including the convergence and integration with the traditional design process, the supporting work organization model, process optimization, and specification, and proposed the airframe stakeholder need capture model based on the theory of systems engineering. Practice has shown that the requirements engineering implementation strategy introduced in this paper can effectively resolve conflicts and redundancies between the requirements system and the original top-level document system requirements. It ensures clear requirements sources, sufficient basis, reasonable allocation, controllable changes, adequate change assessments, clear design status, and controllable design risks. It effectively overcomes human resource bottlenecks during the early stage of requirements engineering implementation while cultivating talent reserves for systems engineering implementation, saving approximately 23.5 person-years in labor costs. It significantly optimizes non-value-added processes, reducing approximately 100 reports. It unifies the team’s understanding of requirements work, improves coordination efficiency, and significantly improves the requirements validation rate between aircraft-level and system-level requirements by an average of approximately 46%. It assists stakeholders and engineers in systematically and scientifically capturing product requirements during the design phase, with original product design specifications covering approximately 70% of subsystem specifications on average. Given its generality across the airframe forward design domain, the airframe requirement management paradigm established by this implementation strategy holds significant importance for the comprehensive and in-depth application of systems engineering methods in commercial aircraft development.
Sun, Luyan, Chang, Liang
To address the failures observed in aluminum-alloy fuel tanks, specifically, cracking of the dual-chamber sealing partition, end cover, and drain boss, finite element analysis was employed for comprehensive calculation and structural optimization. Stress, strain, and displacement under varying load conditions were evaluated, revealing that failures of the sealing partition and end cover were due to stress concentration. At the same time, the cracks in the drain boss were caused by weaknesses in the weld heat-affected zone. Three optimization measures were proposed: adding an R5 chamfer to sealing baffles, incorporating R5 transitional fillets on the reinforcing ribs of the end caps, and designing the drain boss as an asymmetrical elliptical shape with a central transitional fillet. Following these optimizations, the maximum stress on the components was significantly reduced, and the safety factor markedly increased. Results from sealing, pressure, and vibration tests confirmed that these measures effectively enhance the structural strength of aluminum-alloy fuel tanks and extend their service life. This study provides robust support for the design and analysis of aluminumalloy fuel tanks.
Chi, Hong, Lei, Haisen, Sun, Liying, Zhang, Zhitong, Wu, Xiaoci
Driven by increasing engineering demands, the need for high-performance flexible electronics has surged, accelerating the development of stretchable devices within mechanics. Among multilayer structures, the film/substrate architecture serves as a typical example, and its buckling behavior remains a longstanding focus of mechanical investigation. This work examines how an elastic film bonded to a soft tri-layer substrate loses stability, producing wrinkled surface patterns under compression. We first construct a mechanical model, then derive an analytical expression for the wrinkle amplitude using a force-balance approach, and finally employ finite-element simulations and theoretical comparisons, we systematically explore how the middle layer’s stiffness and thickness jointly govern the onset, wavelength and amplitude of surface buckling, revealing quantitative selection rules that have not previously been reported for tri-layer structures. The results show that the tri-layer film/substrate structure exhibits two instability modes: film-intermediate co-buckling and film-only wrinkling. By simply varying the middle layer’s elastic modulus or its thickness, one can move the structure across the boundary that separates the film-only and bi-layer buckling regimes, providing a direct mechanical selection for on-demand mode. In addition, the wrinkle amplitude increases monotonically with the applied initial strain. Those findings offer a theoretical reference for designing flexible electronics based on film/substrate structures.
Chen, Hao, Zhang, Wulin, Song, Yahui
Variable stiffness composite laminates with curvilinear fibres have demonstrated significant capability in lightweight structural design, particularly regarding buckling resistance and stiffness enhancement. However, directly applying optimization algorithms often faces challenges such as high computational cost and slow convergence during the optimization design process. Consequently, the incorporation of surrogate models prior to employing optimization algorithms is necessary to simplify computations and accelerate convergence. Manual testing is a conventional approach for hyper-parameter (HP) tuning and continues to be widely used in research. However, manual tuning is suboptimal and time-consuming for many problems. Additionally, the effectiveness of these surrogate models largely depends on the training samples. Therefore, a dynamic hybrid sampling and adaptive surrogate model HP co-optimization strategy is proposed for the optimization design of the variable stiffness composite laminate with curvilinear fibre. In the numerical results, the performance of different surrogate models, comprising Support Vector Regression (SVR), Radial Basis Function Neural Networks (RBFNN), and Back Propagation Neural Networks (BPNN), is systematically compared under varying sample set sizes. Neural results show significant differences in accuracy and efficiency among these three models under varying sample set sizes. SVR demonstrates optimal generalization ability in small sample scenarios, RBFNN strikes a balance between accuracy and efficiency with medium sample size, while BPNN exhibits superior overall predictive performance under large sample condition. The proposed cooptimization strategy overcomes the limitations of traditional single strategy through the closed-loop interaction between dynamic sampling and Bayesian hyper-parameter optimization (HPO). This approach not only significantly improves the predictive accuracy of surrogate models but also greatly reduces the computational cost during the optimization process, making it suitable for computational mechanics problems with high nonlinearity and high-dimensional features. This study provides theoretical foundations and practical guidance for the selection and application of surrogate models in composite material structural optimization, contributing to improved design process efficiency and reliability.
Chen, Dengnuo, Zou, Rui, Chen, Binqi
A test device for detecting the durability of the surface of elderly-friendly mattresses was designed and developed, which has functions such as force value monitoring, displacement monitoring, data recording, and hardness grade determination. Through the collaborative work of the mechanical system and the control system, high-precision reciprocating rolling tests and hardness grade determination on the mattress surface are realized. The verification test results show that the relative standard deviation (RSD) value of the mattress hardness grade test results is less than 10%, indicating that the detection data obtained by using this device is stable, meets the design requirements, and has operability.
Wang, Jin, Feng, Panpan, Shen, Guofeng, Zhang, Lei
This paper takes a seaplane as the research object, based on the roll damping commonly used in the field of ships, to carry out the applicability analysis and design technology research of the roll damping for the seaplane. A T-tail configuration was selected as the attachment. The design process involved sequentially selecting the horizontal stabilizer airfoil, designing the aspect ratio parameters, and determining the strut airfoil. Consequently, two T-tail design schemes with aspect ratios of 0.76 and 1.53 were proposed. Through the hydrodynamic performance analysis of the T-tail design installed on the seaplane, the advantages and disadvantages of the two T-tail designs in the wave environment are studied. The results demonstrate that the aspect ratio of the T-tail’s horizontal stabilizer directly affects the seaplane’s wave-induced motion response. The proposed design with a larger aspect ratio of 1.53 significantly reduces wave resistance and motion response across various conditions. In the case of a relatively small aspect ratio, the maximum pitching motion is reduced by 38.4%, and the maximum heave is reduced by 59%.
Jiang, Ting, Pi, Xufeng, He, Chao, Wen, Changqing, Li, Xu
Conventional dual-actuator rotational platforms exhibit actuation redundancy that compromises motion precision and increases structural complexity. This paper presents a topology optimization methodology for single-actuator pure rotational platforms to overcome these limitations. A SIMP material interpolation model integrates multi-objective functions, maximizing output rotation angle while minimizing rotational center parasitic displacement under volume fraction constraints. The Optimality Criteria (OC) algorithm was used to solve the optimization problem, with Heaviside density filtering eliminating numerical instabilities. The resulting platform achieves exceptional rotational capability (Rθ = 2.29) while maintaining ultra-low relative parasitic displacements (x: 4.96×10^–5, y: 2.20×10^–5). Parametric studies quantify the influence of volume fractions and stiffness coefficients on performance. The finite element method was employed to analyze the rotation angles and parasitic displacements of both the topology optimization platform and a traditional pure rotation platform. The comparative FEA results demonstrate the superior performance of our topology-optimized design, confirming the effectiveness of the proposed methodology.
Wang, Qiliang, Zhang, Runsheng, Zhang, Shaowen
This paper presents the design, implementation, and validation of an aerial-launch FPV (First-Person View) drone system that was developed to provide a complex environment with flexible deployment and precise delivery capabilities. The integrated system is composed of a hybrid VTOL carrier aircraft, a number of FPV drones, and an aerial mounting / release equipment. Using the AYK-250 platform, the carrier has a vertical take-off and landing function and long-time endurance. In terms of the FPV drones, it is built upon the high performance MARK4 5-inch frame that has high agility and high payload. The release module uses a single-hook point structure with a limit stop. The FPV drones are released stably, and the separation is reliable in flight. Comprehensive flight tests proved all workflows completely, involving carrier take-off, cruise with drones mounted, sequential aerial launch, and subsequent autonomous attitude recovery and route tracking by the FPV drones. The test results confirm the system’s capability for reliable launch from an aerial platform coupled with precise guidance, establishing a credible technical solution for expanding the practical applications of FPV drones in distributed tasks. Results show that our system can be launched via an aerial platform with an accurate guide and is a viable technological solution to spread FPF Drones for operational strategies in a more distributed way.
Wang, Yujie, Xi, Yangyang, Lu, Yafei, Wang, Chengyuan, Zhang, Zhiyong, Chen, Qingyang
This research overcomes the serious problem of unregulated fastener substitution in aviation manufacturing, which is due to supply chain disruption, design modification, improved production, and permanent installation of substitute fasteners other than temporary installation substitutes. It can introduce potential risks, including the differences between designed and as-built configurations, and problems with the structural strength of parts. Analysis of a 20XX aircraft model that has been documented with 9 types of fasteners reveals that shortages of 4CE5 and 1CD6 remain constant manufacturing nonconformities and a major element causing long term quality erosion. We have developed an early warning system centered on data with the introduction of the Tolerable Substitution Ratio (TSR) and the non-substitution ratio (NSR). Empirical results show that after implementation, the substituted materials can save as much as 25%, which is approximately $534,000 on domestic sourcing costs and permanently revised drawing costs. We should consider both users’ specifications and the production facility’s actual capabilities when designing the degree of substitution tolerances; substitution deviating from the original specification would not be tolerated. For an extended cycle longer than one year, phase adaptive tolerance adjustments are critical for achieving the acceptable quality limit (AQL). Real-time alignment of the key trigger point in the process stream with supply chain analytics takes away the historical trade-off between operational efficiency and the quality of the final deliverable. The result of this process is that there were more than 1,600 fewer ad-hoc deployments but higher levels of system stability, even as the processes had become more unstable. The payoff in terms of verified protocols for mitigating risk was much greater.
Feng, Yu
To obtain additional space for industrial sorting and assembly line labeling operations, this study conducts an analysis of the four-bar mechanism. Based on this analysis and combination, the redundant parallel mechanism is introduced. That is, on the basis of the traditional parallel mechanism with central rotation, the objective of expanding the working space is achieved. The degree of freedom of the screw theory and the disparities between the working space of this mechanism and that of the traditional mechanism are analyzed. Finally, through application analysis, it is demonstrated that the working space of this mechanism is variable and that the mechanism can adapt to diverse workplaces.
Li, Wenqian, Zhang, Xiaojie
Civil aircraft, as typical complex product systems, exhibit characteristics such as a high concentration of high-tech technologies, strong interdisciplinarity, a high level of system integration, long development cycles, substantial project investments, and complex management. During the R&D process of civil aircraft projects, there are often high risks in performance, cost, and schedule. Delays in the schedule can lead to losses in project manpower and material resources, as well as project failure. A mature objective criteria system for maturity assessment provides a reference basis for determining whether the project has reached its optimal state at a specific stage, thereby reducing project management risks and increasing the probability of project success. This research will adopt a research approach combining theoretical studies with practical case analysis. First, it will conduct extensive and in-depth investigations into various maturity models and their applications across the entire product lifecycle within relevant fields. A requirement maturity model and requirement maturity KPI (Key Performance Indicator) indicators will be established to clarify the maturity status of requirements at different development stages, enabling judgment of whether the project is ready to proceed to the next development phase. Concurrently, by developing a KPI statistical system platform integrating application servers and data processing tools, a scientific and quantitative inspection mechanism will be implemented to visualize project development progress, status, and risk data. This will provide actionable insights for project decision-making and achieve effective project management and control.
Wang, Yi, Huang, Junkai, Zhang, Xinyu
Efficient optimization of aerodynamic shapes is a critical challenge in aircraft design. Traditional CFD-based optimization workflows suffer from high computational costs and low efficiency, which severely restricts their practical engineering application. In this paper, a novel aerodynamic optimization method based on a hierarchical neural network with adaptive activation functions is proposed. The network adopts learnable B-spline activation functions and is hierarchically constructed in accordance with the sharing status of B-spline control points. After being trained to achieve fast and accurate prediction of aerodynamic performance, the network can effectively replace the traditional CFD module in the optimization loop. The primary advantage of the proposed method is that it significantly reduces the computational cost during the optimization process while ensuring that the prediction accuracy is not compromised. This work thereby presents a novel strategy and technical framework for streamlining the design process of hypersonic vehicles.
Liu, Di, Wang, Yongfeng, Wen, Hong, Wei, Yuanhang, Ma, Hengwei, Zhao, Runhui
With the country’s economy and people’s consumption capacity increasing, railroad transportation tasks have become more and more frequent, and it is growing the demand for the transportation of high-value goods, fresh produce, etc. Compared with traditional Freight vehicles, express freight vehicles have great advantages in terms of carrying capacity, mobility, and transportation cost, but when it run at a speed of 160 km/h, it often occurs that failure of axle-box rubber springs, primary vertical dampers, secondary lateral dampers, anti-yaw dampers, and air springs. How to ensure the safety and stability of the train under suspension system failure conditions is a problem that needs to be solved during the design process. In this paper, through multi-body system dynamics software, a nonlinear dynamics model of lateral and vertical coupling of the vehicle system is established to analyze the influence of suspension system failure on the stability of 160 km/h express freight vehicles. The analysis results show lowering the operating speeds can meet the Ride Quality of the Vehicles in special conditions.
Gao, Zhixiong, Ma, Kai, Xiao, Yanmei, Chen, Weidong, Wei, Xiao, Sha, Chengyu, Bian, Huihui
This study looks into the performance traits of a pure electric car that has a continuously variable transmission (CVT) system by doing careful simulations. The research is mostly about checking how well it performs dynamically and how much better its energy efficiency is compared to regular designs. With the help of AVL Cruise software, a detailed drivetrain model was made to test things like how fast it can accelerate, its top speed, how well it climbs hills, and how much energy it uses when driven in standard ways. The simulation results show some big improvements: the CVT car can go from 0 to 100 km/h in 12.92 seconds, which is 14% quicker than expected; it can reach a top speed of 179 km/h, 15% higher than planned; and it can climb really steep hills at a 41.33% gradient. The energy efficiency analysis also found that it uses less power, consuming just 15.88 kWh per 100km under NEDC conditions and 13.72 kWh per 100km in UDC cycles, which are 21% and 24% less than before. These results prove that the CVT works well in keeping the motor running efficiently by changing ratios all the time. The study points out the technical benefits of CVT systems in making performance and energy saving balanced, but it also finds some practical problems like environmental factors and system integration issues. This work gives useful ideas for making new electric vehicle transmission systems and hints at good ways to improve them in the future.
Chen, Haishan, Gong, Naifa, Pan, Yulong, Cai, Zhicheng, Gao, Yujie, Shen, Xiaobing, Fu, Xianlan, Chen, Keren
This article presents a cross-layer framework that integrates realistic vehicle-to-network-to-vehicle (V2N2V) delay characterization with a rigorous stability analysis of automated vehicle steering control. Both constant and network-induced time-varying delays modeled via deterministic bounds are addressed. For constant delays, delay-independent stability regions within the controller gain space are analytically derived. For time-varying delays with stochastic network origins, modeled using deterministic bounds, a refined Lyapunov–Krasovskii functional (LKF) incorporating augmented single- and double-integral terms is constructed. To establish delay-dependent linear matrix inequality (LMI) conditions, a reciprocally convex combination approach is employed to handle the delay interval partitioning, and the second-order Bessel–Legendre inequality is applied to tighten the integral quadratic bounds. The resulting LMI conditions explicitly capture the coupled effects of delay magnitude, delay variation rate, and control gains on closed-loop stability. Simulations of a lane-keeping scenario confirm that the predicted stability boundaries accurately match the closed-loop system behavior. Notably, incorporating a realistic time-varying V2N2V delay profile into the controller design reduces the lateral-state root-mean-square error (RMSE) by over 54% and decreases the settling time by a factor of 10 compared to designs relying on an average-delay assumption. However, high packet loss rates are shown to still induce residual oscillations due to information scarcity. Ultimately, these results elucidate delay-induced instability mechanisms and provide practical guidelines for designing delay-robust steering controllers for connected and automated vehicles.
Li, Jialin, Lu, Jianwei, Wei, Heng, Ao, Di
Vehicle sound packages are usually designed to provide a given level of vehicle Noise, Vibration, and Harshness (NVH) comfort, within weight and cost constraints. Optimal comfort results can be obtained by considering the interaction of all the parts as a full physical system. So far, extensive research has already been performed and published on optimizing vehicle sound packages to achieve effective noise reduction at lowest cost and weight. Nowadays, due to the urgency of the transition to carbon neutrality, sound packages must also address the reduction of the full vehicle life cycle carbon emissions. Sound package components should use materials that have a low emission impact during production and that are suitable for recycling at the end of the vehicle’s life. This entails reconsidering the material solutions chosen for the sound package as a whole, rather than for each individual component. This article describes possible differentiations in the design of a sound package involving NVH, sustainability, and weight/cost requirements. The study examines how interior and exterior trim components were combined to achieve both optimal NVH and polymer rationalization, through the introduction of mono-material parts and focusing in particular on the use of a new polyester fiber-based floor decoupler, which achieves comparable NVH performance to polyurethane foam without affecting static compression. The article summarizes the vehicle-level performance related to NVH, sustainability, and weight for three sound packages prioritizing either NVH, sustainability or material cost, including a breakdown to analyze the contributions of various components to the overall outcome. A simple metric is introduced to evaluate sustainability, including material, production, use-phase and end-of-life related Greenhouse Gas (GHG) emissions [7–10]. The NVH evaluation involves measuring airborne transfer functions (ATF), complemented by indoor road noise tests. NVH improvements were achieved without an increase in weight, and weight reduction was also possible without negatively impacting NVH performance, both results enhancing the carbon footprint.
Courtois, Theophane, Cardillo, Marco, Criscione, Mattia, Gerges, Youssef, Massocco, Andrea
Vehicle electrification and increasing demands for driving comfort present significant challenges for designing effective noise control treatments (NCTs) in modern vehicles. Lightweight, low-emission designs often compromise acoustic efficiency. A popular and efficient way of compensating for this is through the use of multi-layer ‘trim’ material configurations to noise radiating surfaces to mitigate noise across a wider frequency range. Traditional 3D finite element models, while accurate and even needed to capture the full dynamic behaviour, become computationally prohibitive for complex automotive structures like firewalls, which feature intricate shapes, high curvature, and material compression. This computational burden limits design exploration and timely noise performance predictions. To overcome these limitations, this paper presents an innovative adaptive higher-order finite element method to evaluate the sound transmission loss (STL) of automotive, including the effect of poro-elastic and viscoelastic soundproofing materials. To show its capabilities, a digital twin was developed for a STL test setup for a production vehicle firewall with and without NCT. We present simulation results for different firewall configurations, comparing them against experimental data for the panel STL levels and relative improvements due to a NCT modification. The findings demonstrate the method's accuracy, efficiency, and applicability to real-world automotive engineering problems and also shed light on the trade-offs between model idealization and fidelity of the digital twin.
Van Genechten, Bert, Vansant, Koen, Purohit, Bimal, Effinger, Veronika
In the automotive industry, controlling noise transmission through vehicle components is essential for passenger comfort and regulatory compliance. Traditionally, Transmission Loss (TL) is estimated using simplified CAD-based metrics, which lack accuracy at high frequencies and for complex assemblies. Modeling complex vehicle components introduces challenges, such as representing fluid-structure and trim interactions, with spatially varying trim thicknesses. This study presents an industrial application implementing the Virtual SEA (Statistical Energy Analysis) method to evaluate TL for a firewall. The study discusses strategies for subsystem adaptation and analytical trim modeling, highlighting the importance of managing spatial averaging effects. The proposed workflow integrates laboratory measurements of trim materials, advanced subsystem definition, diffuse sound field (DSF) excitation and radiation in free-field condition. Virtual SEA results are systematically validated against Finite Element Method (FEM) simulations (where the frequency range allows) and experimental data. Virtual SEA demonstrates strong agreement with FEM, especially at mid and high frequencies where FE starts to be cumbersome, confirming its suitability for industrial Noise, Vibration, and Harshness (NVH) applications. While some limitations remain—such as the inability to fully model mixed-component subsystems—ongoing research and practical workarounds are proposed. In conclusion, the Virtual SEA approach enables accurate and efficient TL prediction for vehicle components up to higher frequencies that FEM can achieve, supporting NVH targets and facilitating knowledge transfer to engineering teams. This work advances simulation-based acoustic transparency analysis for modern automotive design.
Orselli, Joseph, Jacquemin, Gaetan, Park, MyeongMan
As acoustic requirements for NVH trim components become increasingly constrained by mass, cost, and sustainability targets, traditional approaches to inner dash design based on spatially averaged Transmission Loss (TL) metrics are reaching their practical limits. In fully built vehicles, the acoustic performance of the inner dash is governed by its global insulation capability but also by strong spatial heterogeneity and its interaction with spatially distributed noise sources such as the power unit, gearbox, and tyre-road excitation. This paper presents a test-based methodology for the spatial optimisation of inner dash acoustic performance using reciprocal holography. By applying a calibrated sound power source within the vehicle cabin and measuring the reciprocal response in the engine bay and wheel-arch regions, a high-resolution spatial Transmission Loss “hologram” of the inner dash is obtained under in-situ conditions. The resulting spatial data enables the identification of localised acoustic weak points that are not observable using conventional testing methods. To bridge the gap between passive component characterisation and real-world vehicle operation, the spatial TL hologram is subsequently evaluated using representative operational source sound power data to prioritise acoustically relevant regions. This enables the transmitted acoustic energy to be evaluated under realistic driving conditions. The holographic data is then coupled with a parametric acoustic model of the inner dash system, allowing localised mass redistribution to be optimised using a genetic algorithm while respecting packaging and manufacturing constraints.
Harry, Evan, Eandi, Giacomo
Achieving favorable Noise, Vibration, and Harshness (NVH) and durability performance in vehicles requires sufficient static and dynamic stiffness of the Body-in-White (BIW). Virtual development of BIW performance targets during the early design stages is essential to minimize costly modifications in later phases. In the automotive industry, full-scale finite element models are widely used for this purpose, offering high fidelity and enabling comprehensive performance evaluations. However, their complexity and high computational cost limit their practicality for early-stage sensitivity and optimization studies. Beam-based models offer a faster alternative; however, conventional beam formulations based on Euler–Bernoulli or Timoshenko beam theories often fail to capture the complex deformation behaviors of thin-walled structures, which are typical of BIW designs. This typically results in poor correlation with detailed models unless artificial joint flexibility is introduced at structural connections. To address these limitations, this study proposes a hybrid modeling approach that combines Higher-Order Beam (HOB) elements with shell elements. HOB elements account for sectional deformation modes—such as warping and distortion—beyond standard translational and rotational degrees of freedom, enabling a more accurate representation of thin-walled member behavior. This work extends previous research by applying HOB theory to BIW modeling, including panel components such as the floor and roof. Comparative analyses with detailed 3D models demonstrate strong agreement, validating the accuracy and efficiency of the proposed method. The results highlight the potential of HOB-based hybrid models as reliable, computationally efficient tools for early-stage BIW design evaluation and layout optimization.
Kim, Jin Hong, Gang-Won, Jang
Electric high voltage (HV) cables are commonly used in automotive applications and very prominently in electrified vehicles. These cables are potential flanking transmission paths for structure-borne sound in a broad frequency range and must therefore be included in the NVH design process. Electrical high voltage cables exhibit non-linear mechanical characteristics, when exposed to significant bending the internal geometry of the cable will change and a curvature dependent bending stiffness will result. The electrical cables envisaged in the current publication feature a helically wound stranded aluminium wire core. This conductive core is covered by, in sequence, a silicone rubber insulation, a braided aluminium wire shield with aluminium foil to minimize electromagnetic interference and a silicone rubber outer sheath. An extensive measurement campaign was carried out to dynamically characterize cable specimen of different lengths and cross sections in terms of multi-degree of freedom transfer stiffnesses from 20 to 2000 Hz. In order to investigate possible temperature dependences this dynamic characterisation was carried out for temperatures ranging from -30 until +60 °C. Moreover, additional measurements on bent cable specimen allowed to assess the dependence of the bending stiffness on the cable curvature. It is shown that suitable results can be obtained by modelling the conductive core using an isotropic multi-layer continuum model and by using corrected material characteristics to account for curvature effects. Temperature effects are shown to be negligible within the tested range.
Nijman, Eugene, Buchegger, Blasius, Böhler, Elmar, Zeller, Bernhard, Rejlek, Jan, Faksa, Lukáš, Lukavsky, David
Digital engineering practices in aerospace increasingly require closely connected and traceable analysis workflows rather than isolated finite element tasks. Traditional FEA methods remain effective, but they involve considerable manual effort during pre- processing and post-processing, making rapid iteration difficult. Finite Element Analysis of STructures (FEAST), an indigenous finite element analysis software developed by Vikram Sarabhai Space Centre (VSSC) ISRO, offers structural analysis capabilities through a command-based architecture, yet its manual operation limits its use in automated studies. This work develops a flexible scripting-driven framework that links geometry creation, load-case definition, solver execution, and result interpretation within a unified digital engineering pipeline. The framework automates repetitive tasks, incorporates Design of Experiments (DoE) for systematic parameter variation, and supports sensitivity and automation studies. Its performance is demonstrated through the analysis of a conical adaptor subjected to two load cases. Across 9720 automated simulations, the workflow identified feasible thickness configuration that satisfied frequency (>125 Hz), buckling (>3.0) and bolt factor-of-safety (>1.0) constraints, while achieving an overall 5% reduction in structural mass. The framework establishes a scalable approach for integrating FEAST within a modern digital engineering environment and enables reproducible, consistent evaluation of complex aerospace structures.
Gupta, Shivangi, T J, Raj Thilak, P, Deepak
This paper presents a multi-physics modeling approach for a hybrid propulsion system designed for High-Altitude Long-Endurance Unmanned Aerial Vehicles (HALE UAVs), integrating solid oxide fuel cells (SOFCs), lithium-ion batteries, and a jet engine. A dynamic model was developed to analyze the coupled characteristics of pressure, temperature, and power under steady-state conditions. Simulation results demonstrate that the internally integrated system achieves efficient fuel and waste heat recovery, delivering a net power output of 300–700 kW, sufficient to meet the operational demands of HALE UAVs. Key innovations include a heat exchanger maintaining SOFC stack inlet temperatures above 850 K for optimal performance and a compressor-fan subsystem enhancing gas compression efficiency. Experimental validation confirmed the accuracy of the SOFC model, with simulated electrical characteristics aligning closely with empirical data. The proposed hybrid system addresses limitations in specific power and transient response while improving energy density, offering a viable solution for long-endurance flight missions. This study provides a foundational platform for advancing hybrid propulsion technologies in aviation.
Zhang, Lin, Zhang, Di, Zhao, Lulu, Li, Xi
This study focuses on the engineering application and performance evaluation of shipboard carbon capture systems. A process combining amine absorption and membrane separation was constructed, and the combined process was applied to a typical 7000 TEU container ship. After sea trials, the average carbon dioxide capture efficiency achieved by the system exceeded 87%, and the power consumption was maintained within an acceptable range. The integrated system greatly improved the EEXI and CII index levels and verified its economic feasibility in the medium and high carbon price scenario. The payback period of the investment costs was reduced to five years. After port coordination tests, the operability of ship-shore carbon dioxide transfer was verified, which promoted future scalability. The engineering layout, energy recovery design, and operation data worked together to provide a practical solution for maritime decarbonization. This study provides a valuable technical reference for the implementation of the International Maritime Organization (IMO) carbon reduction strategy, and also lays a solid foundation for subsequent legislation and system standardization.
Yang, Yongjian
The design and analysis of the wave plate of the tank body of the low-temperature liquid nitrogen tank car are carried out. According to the design method of the empirical formula, the 0.43 MPa low-temperature mobile liquid nitrogen tank body wave plate with the working temperature of -196°C to -178°C is optimized. According to the analysis and design standards, the stress distribution law of the mobile liquid nitrogen tank body under the forward impact condition is analyzed by the method of numerical analysis. The results show that the stress value will gradually increase near the junction of the tank body and the support, and the parts such as the head, the pad, the angle steel ring, and the Z3848 glass steel pipe meet the requirements of the analysis and design standards. At the same time, the first six orders of the natural mode vibration frequency of the tank body are analyzed, which provides a reliable and effective data analysis for the optimization design of the low-temperature liquid nitrogen tank body wave plate.
Ding, Xuqiang, Ni, Yiwei, Gu, Chen, Yan, Dongdong, Xu, Zhiquan, Wang, Qi
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