摘要：
In this article, the hyperelastic material of resilient wheels of subway vehicles is taken as the research object, a method system of identifying and calibrating the constitutive parameters of hyperelastic model based on joint experiment-simulation-deep learning is proposed. The theoretical analytical expression of the true stress-strain on stretch of the hyperelastic model Yeoh model under uniaxial loading condition is deduced, the accurate stress-strain curve data are captured by performing the compression experiment of cylindrical specimen of rubber component of urban rail transit system resilient wheel, and the initial values of parameters of the Yeoh hyperelastic model are fitted by the experimental data. The true stress-strain response samples of compression specimens under different Yeoh model parameter conditions were obtained by finite element numerical simulation. The Yeoh model's optimal parameters are obtained by training the data using a deep learning technique under the specified compression test stress-strain circumstances. Finite element numerical simulation is utilized to confirm the parameters' accuracy. The radial stiffness test of the resilient wheel rubber component was carried out, and the examination of the resilient wheel rubber component's stiffness analysis using the model parameters that were optimized. The study's findings indicate that the methodological system of identifying and calibrating the hyperelastic model constitutive parameters of the hyperelastic model proposed in this paper by combined experiment-simulation-deep learning has high prediction accuracy for the hyperelastic constitutive model parameters.
In this article, the hyperelastic material of resilient wheels of subway vehicles is taken as the research object, a method system of identifying and calibrating the constitutive parameters of hyperelastic model based on joint experiment-simulation-deep learning is proposed. The theoretical analytical expression of the true stress-strain on stretch of the hyperelastic model Yeoh model under uniaxial loading condition is deduced, the accurate stress-strain curve data are captured by performing the compression experiment of cylindrical specimen of rubber component of urban rail transit system resilient wheel, and the initial values of parameters of the Yeoh hyperelastic model are fitted by the experimental data. The true stress-strain response samples of compression specimens under different Yeoh model parameter conditions were obtained by finite element numerical simulation. The Yeoh model's optimal parameters are obtained by training the data using a deep learning technique under the specified compression test stress-strain circumstances. Finite element numerical simulation is utilized to confirm the parameters' accuracy. The radial stiffness test of the resilient wheel rubber component was carried out, and the examination of the resilient wheel rubber component's stiffness analysis using the model parameters that were optimized. The study's findings indicate that the methodological system of identifying and calibrating the hyperelastic model constitutive parameters of the hyperelastic model proposed in this paper by combined experiment-simulation-deep learning has high prediction accuracy for the hyperelastic constitutive model parameters.
摘要：
In order to explore the failure behaviors of lithium-ion batteries (LIBs) during thermal runaway (TR) under various oven temperatures, this study conducts comprehensive oven box abuse tests to investigate the impact of oven temperature on the characteristics of multidimensional signals during battery failure processes. The temporal relationships among expansion force, voltage, and temperature are revealed across four distinct stages of the thermal abuse process. The results indicate that within the oven temperature range of 150 °C to 250 °C, the LIBs invariably undergo venting, with the venting force ranging from 4000 N to 6422 N. Furthermore, the voltage of the batteries remains relatively stable at approximately 3.33 V before venting. An Internal short circuit and TR events occur once the oven temperature exceeds 180 °C, and the corresponding TR trigger temperatures are approximately 232 °C. Moreover, the abnormal force can be utilized as the earliest warning indicator prior to venting, and the lead time for expansion force warning signals decreases with increasing oven temperature in batteries undergoing TR. This study investigates multidimensional signals to effectively identify battery failures, deepening the understanding of the TR behaviors of batteries under different oven temperatures, and providing valuable insights for early warning and safety design of battery systems.
In order to explore the failure behaviors of lithium-ion batteries (LIBs) during thermal runaway (TR) under various oven temperatures, this study conducts comprehensive oven box abuse tests to investigate the impact of oven temperature on the characteristics of multidimensional signals during battery failure processes. The temporal relationships among expansion force, voltage, and temperature are revealed across four distinct stages of the thermal abuse process. The results indicate that within the oven temperature range of 150 °C to 250 °C, the LIBs invariably undergo venting, with the venting force ranging from 4000 N to 6422 N. Furthermore, the voltage of the batteries remains relatively stable at approximately 3.33 V before venting. An Internal short circuit and TR events occur once the oven temperature exceeds 180 °C, and the corresponding TR trigger temperatures are approximately 232 °C. Moreover, the abnormal force can be utilized as the earliest warning indicator prior to venting, and the lead time for expansion force warning signals decreases with increasing oven temperature in batteries undergoing TR. This study investigates multidimensional signals to effectively identify battery failures, deepening the understanding of the TR behaviors of batteries under different oven temperatures, and providing valuable insights for early warning and safety design of battery systems.
摘要：
Stress-constrained topology optimization under geometrical nonlinear conditions is still an open topic as it often encounter difficulties such as mesh distortion, inaccurate stress evaluation and low computational efficiency. For this purpose, this paper develops a novel parallel-computing based topology optimization methodology for geometrically nonlinear continuum structures with stress constraints. To alleviate the mesh distortions in the low-density regions, a smooth material interpolation scheme from with different penalization for the elastic and nonlinear stiffness is proposed. Moreover, a new hybrid stress finite element formulation is included into the geometrically nonlinear topology optimization to capture a more accurate stress distribution that is less sensitive to mesh distortions. Then, to improve the computational efficiency of geometrically nonlinear and sensitivity analysis, a parallel computing framework based on the assembly free iterative solution is established. Meanwhile, an efficient sparse matrix-vector multiplication strategy, which is applicable to solve the geometrically nonlinear problems, is proposed to exploit the computing power of GPU effectively. Finally, several numerical examples are given to illustrate the efficiency and feasibility of the proposed method.
Stress-constrained topology optimization under geometrical nonlinear conditions is still an open topic as it often encounter difficulties such as mesh distortion, inaccurate stress evaluation and low computational efficiency. For this purpose, this paper develops a novel parallel-computing based topology optimization methodology for geometrically nonlinear continuum structures with stress constraints. To alleviate the mesh distortions in the low-density regions, a smooth material interpolation scheme from with different penalization for the elastic and nonlinear stiffness is proposed. Moreover, a new hybrid stress finite element formulation is included into the geometrically nonlinear topology optimization to capture a more accurate stress distribution that is less sensitive to mesh distortions. Then, to improve the computational efficiency of geometrically nonlinear and sensitivity analysis, a parallel computing framework based on the assembly free iterative solution is established. Meanwhile, an efficient sparse matrix-vector multiplication strategy, which is applicable to solve the geometrically nonlinear problems, is proposed to exploit the computing power of GPU effectively. Finally, several numerical examples are given to illustrate the efficiency and feasibility of the proposed method.
摘要：
Many materials in practical engineering exhibit completely different mechanical properties under tension and compression, such as reinforced concrete materials and fiber-reinforced polymers, etc. However, the existing structural design methods usually assume that the mechanical responses of material structures under tensile and compressive loads are the same (i.e. Symmetrical tension and compression characteristics). Considering that the loads are deterministic, the obtained design results may not meet the service requirements and could potentially cause catastrophic damage. This paper proposes a topology optimization method for the strut-and-tie composite structure model under uncertain load conditions. First, a composite structural model is constructed using three-phase materials with different tensile and compressive properties. Then, the design domain is discretized using the hybrid stress element, and a criterion for determining the state of the element in tension and compression is developed. Furthermore, the bivariate dimension reduction method and Gaussian integration method are employed to quantify and propagate load uncertainty. Moreover, an additional method for determining the state of the element in tension and compression under multiple load conditions is developed. Finally, the sensitivity of the objective function concerning the design variables is derived for both single and multiple load cases. Several examples are used to verify the effectiveness of this method, and the influence of optimization parameters such as different load uncertainty levels and the ratio of the elastic moduli of the tensile material and the compressive material on the design results is studied in detail.
Many materials in practical engineering exhibit completely different mechanical properties under tension and compression, such as reinforced concrete materials and fiber-reinforced polymers, etc. However, the existing structural design methods usually assume that the mechanical responses of material structures under tensile and compressive loads are the same (i.e. Symmetrical tension and compression characteristics). Considering that the loads are deterministic, the obtained design results may not meet the service requirements and could potentially cause catastrophic damage. This paper proposes a topology optimization method for the strut-and-tie composite structure model under uncertain load conditions. First, a composite structural model is constructed using three-phase materials with different tensile and compressive properties. Then, the design domain is discretized using the hybrid stress element, and a criterion for determining the state of the element in tension and compression is developed. Furthermore, the bivariate dimension reduction method and Gaussian integration method are employed to quantify and propagate load uncertainty. Moreover, an additional method for determining the state of the element in tension and compression under multiple load conditions is developed. Finally, the sensitivity of the objective function concerning the design variables is derived for both single and multiple load cases. Several examples are used to verify the effectiveness of this method, and the influence of optimization parameters such as different load uncertainty levels and the ratio of the elastic moduli of the tensile material and the compressive material on the design results is studied in detail.
摘要：
Achieving favorable strength and hydrogen embrittlement (HE) resistance synergy has long been one of the main challenges for developing structural materials. The current work reports a AlCoCrFeNi 2.1 eutectic high-entropy alloy with ultrahigh-strength and well HE resistance, achieved by well controlled selective laser melting process. The dislocation pile-up along the nano cellular B2 phase resulted in the high yield strength of 1065 MPa, ultimate tensile strength of 1263 MPa, and fracture strain of 25.3 %. Although the piled-up dislocations can also assist hydrogen concentration in B2/matrix interface during straining, resulted in the HE crack initiation and propagation along the interface. However, the refined lamellar B2 phase increased the length of the B2/matrix interface, thus decrease the level of hydrogen concentration near the interface and shows improved HE resistance.
Achieving favorable strength and hydrogen embrittlement (HE) resistance synergy has long been one of the main challenges for developing structural materials. The current work reports a AlCoCrFeNi 2.1 eutectic high-entropy alloy with ultrahigh-strength and well HE resistance, achieved by well controlled selective laser melting process. The dislocation pile-up along the nano cellular B2 phase resulted in the high yield strength of 1065 MPa, ultimate tensile strength of 1263 MPa, and fracture strain of 25.3 %. Although the piled-up dislocations can also assist hydrogen concentration in B2/matrix interface during straining, resulted in the HE crack initiation and propagation along the interface. However, the refined lamellar B2 phase increased the length of the B2/matrix interface, thus decrease the level of hydrogen concentration near the interface and shows improved HE resistance.
作者：
Kai Gao;Xunhao Li;Lin Hu;Xinyu Liu;Jinlai Zhang;...
期刊：
IEEE Transactions on Vehicular Technology,2025年74(3):4004-4018 ISSN：0018-9545
作者机构：
[Lin Hu; Xinyu Liu; Jinlai Zhang; Ronghua Du] College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, China;Jiangsu Key Laboratory of Urban ITS, Department of Intelligent Transportation and Spatial Informatics, School of Transportation, Southeast University, Nanjing, China;HNU College of Mechanical and Vehicle Engineering, Hunan University, Changsha, China;[Yongfu Li] Key Laboratory of Intelligent Air-Ground Cooperative Control for Universities in Chongqing, College of Automation, Chongqing University of Posts and Telecommunications, Chongqing, China;[Kai Gao] College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, China<&wdkj&>HNU College of Mechanical and Vehicle Engineering, Hunan University, Changsha, China
摘要：
Accurate trajectory prediction of surrounding vehicles is crucial for ensuring the safety of autonomous vehicles. However, current methods based on neural networks still have room for improvement by further reducing their long-term error. This challenge stems from extracting temporal feature dependencies and mining spatial interactions in lane change scenarios. Previous research has not adequately established the connection between the past and the future features. To this end, we propose a spatial-temporal multi-feature fusion and intention-enlightened decoding (STMF-IE) model that jointly considers all these aspects. Initially, STMF-IE uses multi-head temporal self-attention to establish temporal dependencies that make explicit the extent of information usage at different time steps. The interplay between the neighboring vehicles and the target vehicle is quantitatively depicted through a devised multi-head spatial cross-attention mechanism. Furthermore, a multi-feature fusion module is proposed such that the extracted temporal dependence and spatial interaction features are integrated to reduce the superfluous features. Additionally, a novel mask matrix and an intention-enlightened decoding module are developed to refine the prediction performance in different lane change scenarios. Experimental results show that STMF-IE outperforms state-of-the-art methods for long-term prediction on NGSIM and highD datasets. We improve the RMSE metric by 13%–36% at a prediction horizon of 3$\sim$5 s. We also analyze the spatial-temporal feature correlation through visual results, promoting more interpretation.
作者机构：
[Peng Zhang; Yuyu Li; Yonggang Tong; Yongle Hu; Mingjun Zhang; Cong Mao; Kaiming Wang] College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410114, China;[Jie Wang; Xiubing Liang] National Institute of Defense Technology Innovation, Academy of Military Sciences PLA China, Beijing, China;[Hao Lan] Key Laboratory of Rare Earths, Chinese Academy of Sciences, Beijing, China
通讯机构：
[Yonggang Tong] C;College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha 410114, China
摘要：
Additive manufacturing of hard TiC-based cermets typically employs a high-energy beam as the energy source but suffers from high residual stress and microcracks. Herein, we propose an economical additive-manufacturing process for TiC-based cermets using powder extrusion printing (PEP) combined with pressureless sintering, which overcomes inadequacies such as extensive residual stress and microcracks. Complex cermet parts with high densities are successfully fabricated, thereby experimentally demonstrating the feasibility of this method. The as-produced TiC 60 (Ni 88 Fe 12 ) 40 composites exhibit a typical core-rim structure, which plays an important role in improving the interfacial bonding ability. The sintering temperature has a significant impact on the microstructure and mechanical properties. The flexural strength and microhardness increase first and then decrease at temperatures ranging from 1390 to 1430 °C. Optimum mechanical properties are achieved at 1410 °C with flexural strength and microhardness of 1013±17 MPa and 965±18 HV 0.2 , respectively. The additive-manufactured cermets exhibit superior abrasive resistance and the main abrasive mechanism is adhesive wear accompanied by oxidative wear. The good wear resistance is attributed to the high hardness of the TiC phase and the lubricating effect of the abrasive debris.
Additive manufacturing of hard TiC-based cermets typically employs a high-energy beam as the energy source but suffers from high residual stress and microcracks. Herein, we propose an economical additive-manufacturing process for TiC-based cermets using powder extrusion printing (PEP) combined with pressureless sintering, which overcomes inadequacies such as extensive residual stress and microcracks. Complex cermet parts with high densities are successfully fabricated, thereby experimentally demonstrating the feasibility of this method. The as-produced TiC 60 (Ni 88 Fe 12 ) 40 composites exhibit a typical core-rim structure, which plays an important role in improving the interfacial bonding ability. The sintering temperature has a significant impact on the microstructure and mechanical properties. The flexural strength and microhardness increase first and then decrease at temperatures ranging from 1390 to 1430 °C. Optimum mechanical properties are achieved at 1410 °C with flexural strength and microhardness of 1013±17 MPa and 965±18 HV 0.2 , respectively. The additive-manufactured cermets exhibit superior abrasive resistance and the main abrasive mechanism is adhesive wear accompanied by oxidative wear. The good wear resistance is attributed to the high hardness of the TiC phase and the lubricating effect of the abrasive debris.
摘要：
To support regulations related to cyclists dismounting and pushing across motor vehicle lanes, this study first extracted posture parameters for riding/pushing through physical experiments, then simplified the posture parameters and extracted typical postures with distinguishability. Finally, simulated experiments were designed to compare the differences in human injury between riding and pushing in collision accidents. The physical experiment found that the bicycle controller's (individuals who ride or push bicycles) forward leaning angle of the back (referred to as the 'back angle') when riding can be estimated by the ratio of saddle height to bicycle handlebar height, but the back angle when pushing is not affected by other parameters. Eight typical postures containing only lower limb posture parameters were then identified, and statistical analysis showed significant differences in over 80% of parameters among the postures. Through simulated experiments, the rider's tolerable saddle height was identified. Even at this saddle height, the injury in riding state was still significantly higher than that in the pushing state, indicating that pushing the bicycle across the motor vehicle lane can reduce the injury to the bicycle controller. The research results not only support relevant regulations, but also provide typical postures for the bicycle controller in vehicle-bicycle collision experiments in the future, and have certain theoretical and practical value.
摘要：
In this work, interstitial carbon has been employed to further enhance the mechanical and anti-corrosion properties of a metastable quinary Fe 40 Mn 10 Co 20 Cr 20 Ni 10 (at. %) high-entropy alloy (HEA). Both the C-free and C-doped (0.5 at. %) HEAs exhibit a face-centered cubic (FCC) single-phase structure after annealing. Upon tensile deformation, martensitic transformation prevails in the C-free alloy with the formation of hexagonal closed packed (HCP) phase, whereas dislocation slip and twinning are the dominant deformation modes in the C-doped HEA. Such shift of deformation mechanisms can be attributed to the carbon induced increase of stacking fault energy (SFE) (from ∼10 to ∼15 mJ/m 2 ). Simultaneous increases of strength and ductility are achieved in this HEA system by carbon alloying. Carbon-induced interstitial solid solution strengthening effect contributes to the increased stress level, whereas the promoted twinning behavior contributes to the enhanced strain hardening ability. Besides, electrochemical corrosion analysis demonstrates that interstitial carbon reduces the active current density and accelerates the passivation process of the HEA upon immersion in 0.1M H 2 SO 4 solution, contributing to the enhanced corrosion resistance. The findings offer insights into the design of strong, ductile and corrosion-resistant alloys.
In this work, interstitial carbon has been employed to further enhance the mechanical and anti-corrosion properties of a metastable quinary Fe 40 Mn 10 Co 20 Cr 20 Ni 10 (at. %) high-entropy alloy (HEA). Both the C-free and C-doped (0.5 at. %) HEAs exhibit a face-centered cubic (FCC) single-phase structure after annealing. Upon tensile deformation, martensitic transformation prevails in the C-free alloy with the formation of hexagonal closed packed (HCP) phase, whereas dislocation slip and twinning are the dominant deformation modes in the C-doped HEA. Such shift of deformation mechanisms can be attributed to the carbon induced increase of stacking fault energy (SFE) (from ∼10 to ∼15 mJ/m 2 ). Simultaneous increases of strength and ductility are achieved in this HEA system by carbon alloying. Carbon-induced interstitial solid solution strengthening effect contributes to the increased stress level, whereas the promoted twinning behavior contributes to the enhanced strain hardening ability. Besides, electrochemical corrosion analysis demonstrates that interstitial carbon reduces the active current density and accelerates the passivation process of the HEA upon immersion in 0.1M H 2 SO 4 solution, contributing to the enhanced corrosion resistance. The findings offer insights into the design of strong, ductile and corrosion-resistant alloys.
摘要：
A novel formulation for non-convex polygon mesh based on cell-based smoothed finite element method (CS-FEM) is presented for analyzing heat conduction. The major ingredient of this article include: 1) An inverse coordinate mapping method is proposed by using arbitrary polygons of shapes such as "dog", "bird", "cow" obtained from images to discretize the problem domain; 2) The Ear clipping triangulation technique is used to construct a triangular smoothing domain consisting only of field nodes; 3) The element integral is transformed into the boundary integral of triangular smoothing domain, thereby achieving temperature gradient smoothing operation, using the gradient smoothing technique, Well behaved smoothed stiffness matrix is achieved through the gradient smoothing technique of S-FEM in concave polygon elements without the need to construct additional stability terms. Based on the weakened weak form theory, the discretized system equations of heat conduction problem are established, which a symmetric and well-conditioned. The efficacy and robustness of the proposed method has been has been demonstrated through a number of benchmark examples including multi-material systems. It can effectively solve heat conduction problems using concave polygon elements, allowing materials with complex configuration being effectively modeled.
A novel formulation for non-convex polygon mesh based on cell-based smoothed finite element method (CS-FEM) is presented for analyzing heat conduction. The major ingredient of this article include: 1) An inverse coordinate mapping method is proposed by using arbitrary polygons of shapes such as "dog", "bird", "cow" obtained from images to discretize the problem domain; 2) The Ear clipping triangulation technique is used to construct a triangular smoothing domain consisting only of field nodes; 3) The element integral is transformed into the boundary integral of triangular smoothing domain, thereby achieving temperature gradient smoothing operation, using the gradient smoothing technique, Well behaved smoothed stiffness matrix is achieved through the gradient smoothing technique of S-FEM in concave polygon elements without the need to construct additional stability terms. Based on the weakened weak form theory, the discretized system equations of heat conduction problem are established, which a symmetric and well-conditioned. The efficacy and robustness of the proposed method has been has been demonstrated through a number of benchmark examples including multi-material systems. It can effectively solve heat conduction problems using concave polygon elements, allowing materials with complex configuration being effectively modeled.
摘要：
Metal matrix composite (MMC) coatings with good metallurgical bonding were fabricated using laser cladding, focusing on the effect of SiC ceramic contents on the tribological properties and oxidation resistance of nickel matrix composite coatings. The results demonstrated that the microhardness of MMC coatings increased by a factor of 2.28–3.16 and 1.20–1.38, respectively, over the substrate and metal coating under the synergistic action of multiple strengthening effects. As SiC content increases, the wear resistance of coatings shows a trend of first enhancement and then decrease, but both are better than the SiC-free coating and substrate. Where the MMC coating with 15 wt% SiC addition showed the best tribological performance at room and high temperatures, the wear rate was reduced by 71.54 %/ 49.28 % (RT) and 58.8 %/38.17 % (HT) compared to the metal coating and the substrate, respectively, which was mainly attributed to its highest microhardness and densest microstructure. After prolonged oxidation at elevated-temperature, the uniformity and densification of the oxide film on the coating surface increased with increasing SiC content, and the oxidation resistance was linearly strengthened. The synergistic effect of uniformly distributed stable oxide Cr 2 O 3 and self-repairing SiO 2 led to a remarkable improvement in the oxidation resistance of MMC coatings.
Metal matrix composite (MMC) coatings with good metallurgical bonding were fabricated using laser cladding, focusing on the effect of SiC ceramic contents on the tribological properties and oxidation resistance of nickel matrix composite coatings. The results demonstrated that the microhardness of MMC coatings increased by a factor of 2.28–3.16 and 1.20–1.38, respectively, over the substrate and metal coating under the synergistic action of multiple strengthening effects. As SiC content increases, the wear resistance of coatings shows a trend of first enhancement and then decrease, but both are better than the SiC-free coating and substrate. Where the MMC coating with 15 wt% SiC addition showed the best tribological performance at room and high temperatures, the wear rate was reduced by 71.54 %/ 49.28 % (RT) and 58.8 %/38.17 % (HT) compared to the metal coating and the substrate, respectively, which was mainly attributed to its highest microhardness and densest microstructure. After prolonged oxidation at elevated-temperature, the uniformity and densification of the oxide film on the coating surface increased with increasing SiC content, and the oxidation resistance was linearly strengthened. The synergistic effect of uniformly distributed stable oxide Cr 2 O 3 and self-repairing SiO 2 led to a remarkable improvement in the oxidation resistance of MMC coatings.
摘要：
In practical engineering applications, the vibration is often generated in various directions and can be harmful to the engineering equipment. Thus, it is necessary to develop vibration isolators that can reduce vibration in multiple directions. In this paper, we propose a planar two-dimensional vibration isolator based on compliant mechanisms. The proposed mechanism consists of two negative stiffness-compliant modules and two positive stiffness-compliant modules, which leads to the quasi-zero stiffness (QZS) property in the mechanism. The dynamic model is established by using the third-order Taylor expansion and the harmonic balance method. Based on the dynamic model, the influence of different parameters on the displacement transmissibility is discussed, including damping ratio, system stiffness, and excitation amplitude. Finally, we conducted the vibration isolation experiments and obtained the displacement transmissibility of the isolator. The results verify that the proposed isolator has good isolation performance for low-frequency vibration.
关键词：
Biomimetic control;Neuromuscular reflex;Reflex regulation;Neuromorphic modeling;Prosthetic hand
摘要：
Remarkable compliance of human hands due to muscular biomechanics and neural reflexes, attributes lacking in conventional prosthetic hands. Our prior study replicated neuromuscular reflex in prosthetic control using neuromorphic modeling. Nonetheless, the specific impact of the spinal reflex feedback in biomimetic control on amputees’ manipulation capabilities remains unclear. This study aims to investigate the plausible role of reflex regulation in biomimetic control for tendon-driven prosthetic hands. Eleven subjects with forearm amputations participated in force control tasks and functional tasks. The force control tasks were performed using either the prosthetic forefinger or the entire hand. The functional tasks of varying difficulties included the standard rigid object test (SROT), refined rigid object test (RROT), and fragile object test (FOT). Additionally, the stiffness properties of biomimetic control were tested prior to the human-in-loop evaluations. Closed-loop control (CLC) with integrated proprioceptive feedback and open-loop control (OLC) were employed for assessments. Results showed that the reflex regulation contributed significantly to the increase by 20.4% in success rate, 17.9% in effective throughput, and 65.7% decrease in break rate during in the pressing force control task. CLC consistently outperformed OLC across all indices. Indeed, the gripping force control task revealed comparable trends as well. In functional tasks, the reflex regulation yielded 10.5%, 17.9%, and 146.4% improvements in performance for SROT, RROT and FOT, respectively. The findings highlight the essential role of reflex regulation in biomimetic prosthesis control, providing evidence for enhancing amputees’ fine manipulation abilities by replicating the human sensorimotor functions.
Remarkable compliance of human hands due to muscular biomechanics and neural reflexes, attributes lacking in conventional prosthetic hands. Our prior study replicated neuromuscular reflex in prosthetic control using neuromorphic modeling. Nonetheless, the specific impact of the spinal reflex feedback in biomimetic control on amputees’ manipulation capabilities remains unclear. This study aims to investigate the plausible role of reflex regulation in biomimetic control for tendon-driven prosthetic hands. Eleven subjects with forearm amputations participated in force control tasks and functional tasks. The force control tasks were performed using either the prosthetic forefinger or the entire hand. The functional tasks of varying difficulties included the standard rigid object test (SROT), refined rigid object test (RROT), and fragile object test (FOT). Additionally, the stiffness properties of biomimetic control were tested prior to the human-in-loop evaluations. Closed-loop control (CLC) with integrated proprioceptive feedback and open-loop control (OLC) were employed for assessments. Results showed that the reflex regulation contributed significantly to the increase by 20.4% in success rate, 17.9% in effective throughput, and 65.7% decrease in break rate during in the pressing force control task. CLC consistently outperformed OLC across all indices. Indeed, the gripping force control task revealed comparable trends as well. In functional tasks, the reflex regulation yielded 10.5%, 17.9%, and 146.4% improvements in performance for SROT, RROT and FOT, respectively. The findings highlight the essential role of reflex regulation in biomimetic prosthesis control, providing evidence for enhancing amputees’ fine manipulation abilities by replicating the human sensorimotor functions.
期刊：
Engineering Applications of Computational Fluid Mechanics,2025年19(1) ISSN：1994-2060
通讯作者：
Liu, X
作者机构：
[Liu, Xiang; Lv, Pengxiang; Liu, Xiao] Cent South Univ, Minist Educ, Sch Traff & Transportat Engn, Key Lab Traff Safety Track, Changsha 410075, Peoples R China.;[Liu, Xiang; Lv, Pengxiang; Liu, Xiao] Cent South Univ, Joint Int Res Lab Key Technol Rail Traff Safety, Changsha, Peoples R China.;[Liu, Xiang; Lv, Pengxiang; Liu, Xiao] Cent South Univ, Natl & Local Joint Engn Res Ctr Safety Technol Rai, Changsha, Peoples R China.;[Liu, Xiao] Changsha Univ Sci & Technol, Sch Automot & Mech Engn, Changsha, Peoples R China.
通讯机构：
[Liu, X ] C;Cent South Univ, Minist Educ, Sch Traff & Transportat Engn, Key Lab Traff Safety Track, Changsha 410075, Peoples R China.;Cent South Univ, Joint Int Res Lab Key Technol Rail Traff Safety, Changsha, Peoples R China.;Cent South Univ, Natl & Local Joint Engn Res Ctr Safety Technol Rai, Changsha, Peoples R China.
摘要：
The flow-induced vibration of the outer windshield of high-speed train intensifies as the train's speed increases, impacting stability and safety during operation. The vibration characteristics of outer windshields are crucial for optimizing higher-speed train design. In this paper, proper orthogonal decomposition (POD) in conjunction with the pseudo excitation method (PEM) is applied for flow-induced vibration analysis of windshield. The dynamic model of the windshield is established by mode superposition method to reduce the degrees of freedom of the windshield structure. By utilizing the proper orthogonal decomposition and pseudo excitation method (POD-PEM), the accurate frequency characteristics of the flow-induced vibration dynamics of the windshield can be obtained efficiently. The calculation results are compared with the time-domain response to verify the accuracy and the proposed method. The results from the reduced-order model indicate that this method significantly improves the calculation efficiency. This study can provide a reference for the evaluation and optimization of high-speed train windshields.
作者机构：
[Kefu Yi; Wei Hao] School of Traffic and Transportation, Changsha University of Science and Technology, Changsha, 410114, Hunan, China;[Hao Wu] College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, 410114, Hunan, China;[Rongdong Hu] Changsha Intelligent Driving Institute, Changsha, 410000, Hunan, China
通讯机构：
[Kefu Yi] S;School of Traffic and Transportation, Changsha University of Science and Technology, Changsha, 410114, Hunan, China
关键词：
Multi-object tracking;2D tracking
摘要：
Multi-object tracking (MOT) remains a challenging task in dynamic environments. While most 2D tracking methods focus solely on the image plane, they often neglect the Ground Plane Assumption (GPA) — the principle that targets typically move on a consistent ground plane. This is because camera parameters are difficult to obtain and are not very reliable in scenarios involving camera motion or where the GPA does not apply. To address this issue, we propose EscapeTrack, a novel MOT algorithm that robustly handles imprecise camera parameters. Unlike conventional homography projection methods prone to calibration errors, EscapeTrack innovatively models target coordinates on the ground plane as latent variables within a Kalman filter framework. By constructing an observation model that projects these latent states onto the image plane, our method achieves superior tracking accuracy even with significant parameter noise. Extensive evaluations demonstrate state-of-the-art performance on MOT17, MOT20, DanceTrack, SportsMOT, and BDD100K benchmarks. Notably, EscapeTrack excels in scenarios with camera motion or GPA violations, by inherently treating such cases as camera parameter estimation errors. This robustness enables practical deployment in real-world systems where precise calibration is infeasible, advancing intelligent tracking in complex dynamic environments. The source code will be available at https://github.com/corfyi/EscapeTrack .
Multi-object tracking (MOT) remains a challenging task in dynamic environments. While most 2D tracking methods focus solely on the image plane, they often neglect the Ground Plane Assumption (GPA) — the principle that targets typically move on a consistent ground plane. This is because camera parameters are difficult to obtain and are not very reliable in scenarios involving camera motion or where the GPA does not apply. To address this issue, we propose EscapeTrack, a novel MOT algorithm that robustly handles imprecise camera parameters. Unlike conventional homography projection methods prone to calibration errors, EscapeTrack innovatively models target coordinates on the ground plane as latent variables within a Kalman filter framework. By constructing an observation model that projects these latent states onto the image plane, our method achieves superior tracking accuracy even with significant parameter noise. Extensive evaluations demonstrate state-of-the-art performance on MOT17, MOT20, DanceTrack, SportsMOT, and BDD100K benchmarks. Notably, EscapeTrack excels in scenarios with camera motion or GPA violations, by inherently treating such cases as camera parameter estimation errors. This robustness enables practical deployment in real-world systems where precise calibration is infeasible, advancing intelligent tracking in complex dynamic environments. The source code will be available at https://github.com/corfyi/EscapeTrack .
摘要：
High-speed deformation fracture prediction of aluminum sheet, especially for biaxial tension state deformation, was a major problem in the development of electromagnetic bulging process. In this study, the biaxial tension failure limit of the AA5052 sheet was tested by the electromagnetic high-speed biaxial tensile testing equipment and quasi-static Nakazima experiment. A Digital Image Correlation (DIC) system was used to measure failure strain. Based on the tested data, a failure model considered stress state and strain rate coupling effect was established, which available for electromagnetic bulging failure prediction. Electromagnetic free bulging experiments were conducted to verify the failure criteria effectiveness. Results showed that the strain rate effects of the failure strain were influenced by the loading path. The strain rate effect of the sheet failure strain under plain strain state was higher than the loading stress triaxiality of uniaxial and biaxial tension state. Compared with the fracture prediction criterion ignored stress state effect on strain rate influence factor, the modified fracture model considered stress state and strain rate coupling effect could well predict the failure of electromagnetic bulging, which would exhibit different failure models at the rounded corner or the top under different discharge energies.
作者机构：
[Chenxue Hou; Chunlong Fei; Xiongwei Wei; Yiheng Yang; Qi Lu; Yi Quan; Yintang Yang] Shaanxi Provincial Key Laboratory of Integrated Circuit and System Integration, Faculty of Integrated Circuit, Xidian University, Xi’an 710071, China;[Xiaozhou Lü; Weimin Bao] School of Aerospace Science and Technology, Xidian University, Xi’an 710071, China;[Qibo Lin] State Key Laboratory of Precision Manufacturing for Extreme Service Performance, College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, 410114, China;Hunan Province University Key Laboratory of Intelligent Testing and Control Technology for Engineering Equipment, Changsha, 410114, China
通讯机构：
[Zhaoxi Li] S;Shaanxi Provincial Key Laboratory of Integrated Circuit and System Integration, Faculty of Integrated Circuit, Xidian University, Xi’an 710071, China<&wdkj&>School of Aerospace Science and Technology, Xidian University, Xi’an 710071, China
关键词：
Piezoelectric composites;Ultrasonic transducer;Imaging applications;Lateral vibration;Finite element analysis
摘要：
Ultrasonic imaging technology has advanced rapidly, the escalating demand for imaging quality has driven the continuous development of ultrasonic transducers featuring high-performance. Among them, the crucial factors constraining the further enhancement of imaging quality are the frequency of the device and the intensity of the echo signal. Piezoelectric composites have become a hotspot for ultrasonic transducers and imaging applications due to their excellent properties. However, due to the limitations of the accuracy of the cutting process, the development of piezoelectric/polymer composites is often undermined by undesirable pseudo-vibrations, especially in high-frequency applications, which will significantly reduce energy conversion efficiency. In this study, a novel design method of 1-3 piezoelectric composites with gradient nanoparticle doped polymer is proposed to eliminate the undesired lateral vibrations. Based on the optimized composites, a high-performance composite ultrasonic transducer with a center frequency of 8.51 MHz is prepared. Compared with the traditional composite transducer, the optimized transducer improves the echo voltage amplitude significantly, reaching nearly 3 times. The above advantages are further verified in high-quality ultrasound and photoacoustic imaging. The optimization method has valuable guidance for the design of high-frequency composite transducers, which have great potential in ultrasonic and photoacoustic imaging applications.
Ultrasonic imaging technology has advanced rapidly, the escalating demand for imaging quality has driven the continuous development of ultrasonic transducers featuring high-performance. Among them, the crucial factors constraining the further enhancement of imaging quality are the frequency of the device and the intensity of the echo signal. Piezoelectric composites have become a hotspot for ultrasonic transducers and imaging applications due to their excellent properties. However, due to the limitations of the accuracy of the cutting process, the development of piezoelectric/polymer composites is often undermined by undesirable pseudo-vibrations, especially in high-frequency applications, which will significantly reduce energy conversion efficiency. In this study, a novel design method of 1-3 piezoelectric composites with gradient nanoparticle doped polymer is proposed to eliminate the undesired lateral vibrations. Based on the optimized composites, a high-performance composite ultrasonic transducer with a center frequency of 8.51 MHz is prepared. Compared with the traditional composite transducer, the optimized transducer improves the echo voltage amplitude significantly, reaching nearly 3 times. The above advantages are further verified in high-quality ultrasound and photoacoustic imaging. The optimization method has valuable guidance for the design of high-frequency composite transducers, which have great potential in ultrasonic and photoacoustic imaging applications.
摘要：
This paper demonstrates a stacking sequence optimization method for variable thickness composite laminated plates via multi-peak stacking sequence table (MPSST). “Multi-peak” refers to the capability of composite plates to have non-monotonic thickness variations, allowing multiple peak thicknesses across different regions. To enhance design flexibility and obtain better optimization results, this study divides the composite laminated plate into several sub panels using local minimum thickness and generates various ply structures through ply-by-ply insertion from the dividing area. The concept of MPSST is developed to describe the ply drop sequence between dividing area and sub panels, which can expand the design space while maintaining ply continuity. Then the stacking sequence optimization problem is transformed into the optimization design of multiple variables in MPSST. Through optimizing the stacking sequence of the thinnest region and inserted plies of sub panels, the optimum stacking sequences of multiple regions are obtained, which can decrease the total number of optimization variables and increase the manufacturability of optimization results. The application example of the 18-region composite plate shows that the proposed methodology can reduce the total weight from 28.55 kg with the traditional SST method to 27.89 kg, representing a reduction of 2.31 %, demonstrating its effectiveness and accuracy.
This paper demonstrates a stacking sequence optimization method for variable thickness composite laminated plates via multi-peak stacking sequence table (MPSST). “Multi-peak” refers to the capability of composite plates to have non-monotonic thickness variations, allowing multiple peak thicknesses across different regions. To enhance design flexibility and obtain better optimization results, this study divides the composite laminated plate into several sub panels using local minimum thickness and generates various ply structures through ply-by-ply insertion from the dividing area. The concept of MPSST is developed to describe the ply drop sequence between dividing area and sub panels, which can expand the design space while maintaining ply continuity. Then the stacking sequence optimization problem is transformed into the optimization design of multiple variables in MPSST. Through optimizing the stacking sequence of the thinnest region and inserted plies of sub panels, the optimum stacking sequences of multiple regions are obtained, which can decrease the total number of optimization variables and increase the manufacturability of optimization results. The application example of the 18-region composite plate shows that the proposed methodology can reduce the total weight from 28.55 kg with the traditional SST method to 27.89 kg, representing a reduction of 2.31 %, demonstrating its effectiveness and accuracy.
通讯机构：
[Tang, K ] C;Changsha Univ Sci & Technol, Sch Automot & Mech Engn, Changsha 410114, Peoples R China.
关键词：
Oxalis corniculata L. leaves;Bionic;Laser-induced graphene;Flexible pressure sensor;Mircojigsaw
摘要：
Laser-Induced Graphene (LIG) is regarded as a promising sensor carrier due to its inherent three-dimensional porous structure. However, as two mutually exclusive properties of the pressure sensor, sensitivity and working range are difficult to be further improved by the single porous structure. Inspired by the unique geometry of Oxalis corniculata L. leaves, we here propose a novel method consist of laser pre-etching and inducing steps to fabricate LIG-based electrodes with a two-stage architecture featuring microjigsaw and microporous structures. The following injection of liquid-silicone significantly improves the friction resistance and bending reliability of LIG materials. The interface contact between external microjigsaw structures induces substantial resistance changes, and the internal microporous structure exhibits reversibility during dynamic deformation. Consequently, the jigsaw-like pressure sensor achieves a balanced performance with sensitivities of 3.64, 1.20 and 0.03 kPa- 1 in pressure range of 0 - 20, 20 - 40 and 40 - 150 kPa, respectively. The bionic LIG-based pressure sensor serves as the core component and further integrated with an all-in-one wireless transmission system capable of monitoring various health parameters such as subtle pulse rates, heartbeat rhythms, sounds, etc., indicating broad prospects in future wearable electronics.
作者机构：
[Yuanqiang Luo; Quancai Zhao; Weidong Tang; Cong Mao; Longzhou Dai; Jize Zhang; Jikai Yao; Abdur Razzak] College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, 410114, China;[Xiaoming Kang] School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
通讯机构：
[Weidong Tang] C;College of Automotive and Mechanical Engineering, Changsha University of Science and Technology, Changsha, 410114, China
摘要：
Engineering ceramics have excellent properties such as high hardness and strength, resistance to high temperature, wear and corrosion, However, these ceramics also pose great challenges to processing techniques. A novel method of powder-mixed electrochemical discharge-drilling hybrid machining (PMECDDM) for alumina ceramics was proposed in this paper. The thermal removal mechanism of alumina ceramics during the hybrid machining process were analyzed. The temperature distribution on alumina ceramics under the action of the single-pulse electrochemical discharge was obtained based on a thermal-fluid coupling multiphysics simulation model. The axial force during the material removal process in mechanical drilling (MD) was comprehensively analyzed. Experiments were conducted under constant force feed condition to investigate the micro-hole machining performance of alumina ceramics by different machining methods. Experimental results revealed that a new form of discharge was generated after the introduction of the micro copper powder into the electrochemical discharge-mechanical drilling hybrid machining process, which increased the local discharge energy and strengthens the softening effect of the discharge on alumina ceramics. Compared to MD, the machined surface of PMECDDM exhibited fewer brittle fracture areas, resulting in improved surface quality. Compared with the conventional electrochemical discharge-drilling hybrid machining (ECDDM), the machining efficiency of PMECDDM was increased by approximately 47 %.
Engineering ceramics have excellent properties such as high hardness and strength, resistance to high temperature, wear and corrosion, However, these ceramics also pose great challenges to processing techniques. A novel method of powder-mixed electrochemical discharge-drilling hybrid machining (PMECDDM) for alumina ceramics was proposed in this paper. The thermal removal mechanism of alumina ceramics during the hybrid machining process were analyzed. The temperature distribution on alumina ceramics under the action of the single-pulse electrochemical discharge was obtained based on a thermal-fluid coupling multiphysics simulation model. The axial force during the material removal process in mechanical drilling (MD) was comprehensively analyzed. Experiments were conducted under constant force feed condition to investigate the micro-hole machining performance of alumina ceramics by different machining methods. Experimental results revealed that a new form of discharge was generated after the introduction of the micro copper powder into the electrochemical discharge-mechanical drilling hybrid machining process, which increased the local discharge energy and strengthens the softening effect of the discharge on alumina ceramics. Compared to MD, the machined surface of PMECDDM exhibited fewer brittle fracture areas, resulting in improved surface quality. Compared with the conventional electrochemical discharge-drilling hybrid machining (ECDDM), the machining efficiency of PMECDDM was increased by approximately 47 %.
