Pub Date : 2024-01-09DOI: 10.1177/09544070231221015
Majid Lotfi, Abolfazl Masoumi
With the quick advancement of the vehicle industry, attention to automobile safety has increased. Crash boxes, which are placed in front of the side rails, play an essential role in preventing much damage to the front part of the car and also protecting passengers. Improving and optimizing these crash boxes’ energy absorption properties is necessary. In this study, a new structure of three-dimensional re-entrant auxetic has been presented for use as a crash box. Quasi-static uniaxial loading has been investigated experimentally and numerically. With the validation of the numerical simulation, the response surface method was implemented to investigate the value and type of different parameters’ effect on peak load and specific absorbed energy. Variables of the base and re-entrant strut thicknesses ( t1) and ( t2), the length of the base to re-entrant strut ( L/H), and the re-entrant angle ( θ) were considered in three levels. Through ANOVA analysis in Design-Expert software, it was found that the parameters t2 and θ had the highest effect on the peak load, energy absorption, specific energy absorption, and mean crashing force responses. With the increasing of t2 and θ, all responses increase and decrease, respectively. Also, multi-objective optimization based on minimum peak load and maximum specific energy absorption was performed by the desirability function method in Design-Expert software and the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. The proposed optimized structure exhibits enhanced energy absorption when compared to the optimized cylindrical auxetic structure and the thin-walled circular structure within the peak load range below 80 kN. Therefore, the proposed structure due to low peak load, uniformity collapse in the force-displacement diagrams, and stability of the structure during compression loading, can be used as the crash box.
{"title":"Multi-objective crashworthiness optimization for a newly developed 3D re-entrant auxetic structure using response surface method and MOPSO algorithm","authors":"Majid Lotfi, Abolfazl Masoumi","doi":"10.1177/09544070231221015","DOIUrl":"https://doi.org/10.1177/09544070231221015","url":null,"abstract":"With the quick advancement of the vehicle industry, attention to automobile safety has increased. Crash boxes, which are placed in front of the side rails, play an essential role in preventing much damage to the front part of the car and also protecting passengers. Improving and optimizing these crash boxes’ energy absorption properties is necessary. In this study, a new structure of three-dimensional re-entrant auxetic has been presented for use as a crash box. Quasi-static uniaxial loading has been investigated experimentally and numerically. With the validation of the numerical simulation, the response surface method was implemented to investigate the value and type of different parameters’ effect on peak load and specific absorbed energy. Variables of the base and re-entrant strut thicknesses ( t1) and ( t2), the length of the base to re-entrant strut ( L/H), and the re-entrant angle ( θ) were considered in three levels. Through ANOVA analysis in Design-Expert software, it was found that the parameters t2 and θ had the highest effect on the peak load, energy absorption, specific energy absorption, and mean crashing force responses. With the increasing of t2 and θ, all responses increase and decrease, respectively. Also, multi-objective optimization based on minimum peak load and maximum specific energy absorption was performed by the desirability function method in Design-Expert software and the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. The proposed optimized structure exhibits enhanced energy absorption when compared to the optimized cylindrical auxetic structure and the thin-walled circular structure within the peak load range below 80 kN. Therefore, the proposed structure due to low peak load, uniformity collapse in the force-displacement diagrams, and stability of the structure during compression loading, can be used as the crash box.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139444165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-09DOI: 10.1177/09544070231218355
Han Zhang, Yuan Li, Weimei Quan, Wanzhong Zhao
To improve the vehicle stability and driver steering performance, this paper presents an individualized yaw stability control strategy based on H∞ robust control for active front steering (AFS) vehicles. A driver-vehicle system, including a driver steering model and a vehicle dynamics model with AFS, is formed. To analyze the steering characteristics of different drivers, a set of driving data of 36 drivers is collected, and the driver’s characteristics parameters are identified by using the particle swarm optimization (PSO) algorithm. A general evaluation function considering the trajectory tracking performance, vehicle stability, driver workloads, and driver’s characteristics parameters are established to evaluate the comprehensive steering performance. To accomplish the personalized control of vehicle yaw stability, an individualized H∞ robust yaw stability controller is presented by adjusting the gain of the weighting function according to the general evaluation of each driver. Driver-in-the-loop experiment is conducted based on the Matlab/Simulink-CarSim®-Prescan co-simulation platform, and the results demonstrates that the proposed control strategy can provide driver with individualized driving assistance while improving the overall driving performance and reducing the driver’s workloads.
{"title":"An individualized robust stability control strategy for active front steering vehicles","authors":"Han Zhang, Yuan Li, Weimei Quan, Wanzhong Zhao","doi":"10.1177/09544070231218355","DOIUrl":"https://doi.org/10.1177/09544070231218355","url":null,"abstract":"To improve the vehicle stability and driver steering performance, this paper presents an individualized yaw stability control strategy based on H∞ robust control for active front steering (AFS) vehicles. A driver-vehicle system, including a driver steering model and a vehicle dynamics model with AFS, is formed. To analyze the steering characteristics of different drivers, a set of driving data of 36 drivers is collected, and the driver’s characteristics parameters are identified by using the particle swarm optimization (PSO) algorithm. A general evaluation function considering the trajectory tracking performance, vehicle stability, driver workloads, and driver’s characteristics parameters are established to evaluate the comprehensive steering performance. To accomplish the personalized control of vehicle yaw stability, an individualized H∞ robust yaw stability controller is presented by adjusting the gain of the weighting function according to the general evaluation of each driver. Driver-in-the-loop experiment is conducted based on the Matlab/Simulink-CarSim®-Prescan co-simulation platform, and the results demonstrates that the proposed control strategy can provide driver with individualized driving assistance while improving the overall driving performance and reducing the driver’s workloads.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-08DOI: 10.1177/09544070231221307
Junliang Du, Dawei Liu, Tingzhi Ren
Jerk during shift in mechanical two-speed transmissions often have a serious impact on driving comfort. Within this paper, a proposed two-speed permanent magnet transmission is presented for low-speed electric vehicles, which utilizes magnetic non-contact transmission. This transmission is composed of a magnetic drive mechanism, a clutch, and a selectable one-way clutch. Then, a mathematical model is established for the magnetic-machine composite transmission based on the principles of magnetic field modulation and the concentrated parameter method. Additionally, a shift method that operates without power interruption is presented. Finally, the process of shifting is simulated for permanent magnet drive systems with varying magnetic coupling stiffness in a MATLAB/Simulink environment. The resulting torque calculations are compared with those obtained from the commercial software Maxwell. Simulation results indicate that the two-speed permanent magnet transmission does not experience power interruption during upshifting. Less jerk when shifting gears. Low magnetic coupling stiffness can reduce high-frequency vibration and enhance shift comfort. The findings from the torque calculations obtained through the proposed model align with those obtained from the commercial software Maxwell.
{"title":"Low-stiffness comfort shift characteristics of a permanent magnet two-speed transmission for low-speed EV","authors":"Junliang Du, Dawei Liu, Tingzhi Ren","doi":"10.1177/09544070231221307","DOIUrl":"https://doi.org/10.1177/09544070231221307","url":null,"abstract":"Jerk during shift in mechanical two-speed transmissions often have a serious impact on driving comfort. Within this paper, a proposed two-speed permanent magnet transmission is presented for low-speed electric vehicles, which utilizes magnetic non-contact transmission. This transmission is composed of a magnetic drive mechanism, a clutch, and a selectable one-way clutch. Then, a mathematical model is established for the magnetic-machine composite transmission based on the principles of magnetic field modulation and the concentrated parameter method. Additionally, a shift method that operates without power interruption is presented. Finally, the process of shifting is simulated for permanent magnet drive systems with varying magnetic coupling stiffness in a MATLAB/Simulink environment. The resulting torque calculations are compared with those obtained from the commercial software Maxwell. Simulation results indicate that the two-speed permanent magnet transmission does not experience power interruption during upshifting. Less jerk when shifting gears. Low magnetic coupling stiffness can reduce high-frequency vibration and enhance shift comfort. The findings from the torque calculations obtained through the proposed model align with those obtained from the commercial software Maxwell.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139446450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-08DOI: 10.1177/09544070231215926
Caixia Huang, Xin Wu, Chenxi Wu, Jiande Wang, Xiong Shu
This study presents a hierarchical control system of handling stability for distributed drive electric vehicles. The desired direct yaw moment (DYM), determined by the upper-level controller, regulates the sideslip angle and yaw rate according to the robust H∞ control strategy. Meanwhile, the lower-level controller proposed in this research consists of a rule-based torque vectoring distribution and wheel slip ratio control. The proposed rule-based torque vectoring distribution strategy (TVDS) permits drive pattern switching based on the wheel slip ratio and preferentially employs the balanced torque vectoring distribution strategy to achieve DYM, wherein the distributed braking torque is achieved by motor regenerative braking. Here, the wheel with serious slipping was managed in a four-wheel drive pattern by the slip ratio controller. Then, the distribution strategies used for differential braking and proposed rule-based torque vectoring with and without slip ratio control were compared and analyzed in vehicle states and actuator outputs, respectively, by setting CarSim/MATLAB cosimulation under two driving conditions. Results demonstrate that the proposed rule-based TVDS can improve handling stability, energy efficiency, and riding comfort. Wheel locking can be successfully avoided by actuating the wheel slip ratio control, subsequently reducing the road adhesion requirements and improving vehicle handling stability and trajectory tracking accuracy.
{"title":"Rule-based torque vectoring distribution strategy combined with slip ratio control to improve the handling stability of distributed drive electric vehicles","authors":"Caixia Huang, Xin Wu, Chenxi Wu, Jiande Wang, Xiong Shu","doi":"10.1177/09544070231215926","DOIUrl":"https://doi.org/10.1177/09544070231215926","url":null,"abstract":"This study presents a hierarchical control system of handling stability for distributed drive electric vehicles. The desired direct yaw moment (DYM), determined by the upper-level controller, regulates the sideslip angle and yaw rate according to the robust H∞ control strategy. Meanwhile, the lower-level controller proposed in this research consists of a rule-based torque vectoring distribution and wheel slip ratio control. The proposed rule-based torque vectoring distribution strategy (TVDS) permits drive pattern switching based on the wheel slip ratio and preferentially employs the balanced torque vectoring distribution strategy to achieve DYM, wherein the distributed braking torque is achieved by motor regenerative braking. Here, the wheel with serious slipping was managed in a four-wheel drive pattern by the slip ratio controller. Then, the distribution strategies used for differential braking and proposed rule-based torque vectoring with and without slip ratio control were compared and analyzed in vehicle states and actuator outputs, respectively, by setting CarSim/MATLAB cosimulation under two driving conditions. Results demonstrate that the proposed rule-based TVDS can improve handling stability, energy efficiency, and riding comfort. Wheel locking can be successfully avoided by actuating the wheel slip ratio control, subsequently reducing the road adhesion requirements and improving vehicle handling stability and trajectory tracking accuracy.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139446967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-06DOI: 10.1177/09544070231217023
Haozhong Huang, Yi Wang, Chengzhong Zhou, Xiaoyu Guo, Kong Xing
As the fourth stage of China’s fuel consumption limits for heavy commercial approaches, engine manufacturers are facing huge challenges. Here, the impact of different strategies on brake thermal efficiency (BTE) was studied through experiments and simulations, and the main energy loss items were obtained based on energy and exergy analysis. According to experimental results, the removal of exhaust gas recirculation (EGR) mainly reduced exhaust losses, resulting in a 0.5% increase in BTE at 1200 r/min. Turbocharger scheme 2, with a high flow rate and high efficiency, was beneficial in reducing pumping losses. Owing to consistent brake power, simultaneously increasing the compression ratio and peak firing pressure can reduce the exhaust losses and combustion irreversibility. When fuel injection quantity was constant, the use of high flow injectors could advance CA50, thereby increasing output power and reducing exhaust losses. Finally, the actual development of the new engine was completed, and the test results showed that the maximum BTE reached 46.9%, and CO and soot emissions were reduced by 74.2% and 78.3%, respectively. Therefore, for medium-sized diesel engines, adopting the non-EGR route, using high flow turbochargers and injectors, and increasing compression ratio can effectively improve BTE and reduce carbon emissions.
{"title":"Effective measures to improve thermal efficiency of medium-sized diesel engine in practical application: Energy-exergy analysis and test verification","authors":"Haozhong Huang, Yi Wang, Chengzhong Zhou, Xiaoyu Guo, Kong Xing","doi":"10.1177/09544070231217023","DOIUrl":"https://doi.org/10.1177/09544070231217023","url":null,"abstract":"As the fourth stage of China’s fuel consumption limits for heavy commercial approaches, engine manufacturers are facing huge challenges. Here, the impact of different strategies on brake thermal efficiency (BTE) was studied through experiments and simulations, and the main energy loss items were obtained based on energy and exergy analysis. According to experimental results, the removal of exhaust gas recirculation (EGR) mainly reduced exhaust losses, resulting in a 0.5% increase in BTE at 1200 r/min. Turbocharger scheme 2, with a high flow rate and high efficiency, was beneficial in reducing pumping losses. Owing to consistent brake power, simultaneously increasing the compression ratio and peak firing pressure can reduce the exhaust losses and combustion irreversibility. When fuel injection quantity was constant, the use of high flow injectors could advance CA50, thereby increasing output power and reducing exhaust losses. Finally, the actual development of the new engine was completed, and the test results showed that the maximum BTE reached 46.9%, and CO and soot emissions were reduced by 74.2% and 78.3%, respectively. Therefore, for medium-sized diesel engines, adopting the non-EGR route, using high flow turbochargers and injectors, and increasing compression ratio can effectively improve BTE and reduce carbon emissions.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The structural parameters of the rolling lobe air spring and the mechanical characteristic of rubber bellows are the key factors affecting the stiffness and mechanical characteristic of the rolling lobe air spring. Aiming at the prediction difficulties of structural parameters of the rolling lobe air spring with the composite curved contour piston and the modeling complexity of the hysteretic mechanical characteristic of rubber bellows under variable pressure conditions, the geometrical method is applied to derive the structural parameters models of the rolling lobe air spring with the composite curved contour piston. A new pressure factor is introduced and the Coulomb frictional pressure perturbation model and the fractional derivative Kelvin-Voigt pressure perturbation model are reconstructed to accurately describe the hysteretic mechanical characteristic of rubber bellows under variable pressure conditions. A unified pressure equation is constructed to characterize the evolution of model parameters under variable pressure conditions. Furthermore, a hysteretic mechanical characteristic pressure perturbation model (abbreviated as HMCPP model) of rubber bellows under variable pressure conditions is put forward. Finally, a unified stiffness model of the rolling lobe air spring including prediction models of nonlinear structural parameters and a HMCPP model of rubber bellows is built. Taking a certain type of rolling lobe air spring as the test sample A, the structural parameters tests and static/dynamic characteristic tests of sample A are carried out based on the MTS852.05 test bench, which verified the accuracy of the unified stiffness model of the rolling lobe air spring. The research results provide theoretical support for the mechanical characteristic matching and air pressure precise control of the rolling lobe air spring under variable pressure conditions.
滚动叶空气弹簧的结构参数和橡胶波纹管的力学特性是影响滚动叶空气弹簧刚度和力学特性的关键因素。针对复合曲面活塞滚动叶空气弹簧结构参数预测的困难性和变压条件下橡胶波纹管滞后力学特性建模的复杂性，应用几何方法推导了复合曲面活塞滚动叶空气弹簧的结构参数模型。引入新的压力因子，重构库仑摩擦压力扰动模型和分数导数开尔文-伏依格特压力扰动模型，以精确描述变压条件下橡胶波纹管的滞后力学特性。构建了统一的压力方程，以描述变压条件下模型参数的演变特征。此外，还提出了变压条件下橡胶波纹管的滞后机械特性压力扰动模型（简称 HMCPP 模型）。最后，建立了包括非线性结构参数预测模型和橡胶波纹管 HMCPP 模型在内的统一的滚动叶空气弹簧刚度模型。以某型滚动叶空气弹簧为试验样本 A，基于 MTS852.05 试验台对样本 A 进行了结构参数试验和静态/动态特性试验，验证了滚动叶空气弹簧统一刚度模型的准确性。研究结果为变压条件下滚动叶空气弹簧的机械特性匹配和气压精确控制提供了理论支持。
{"title":"A unified stiffness model of rolling lobe air spring with nonlinear structural parameters and air pressure dependence of rubber bellows","authors":"Jun-Jie Chen, Zi-Qi Huang, Hong-Jiang Liu, Guangqi Qiu, Yingkui Gu","doi":"10.1177/09544070231214306","DOIUrl":"https://doi.org/10.1177/09544070231214306","url":null,"abstract":"The structural parameters of the rolling lobe air spring and the mechanical characteristic of rubber bellows are the key factors affecting the stiffness and mechanical characteristic of the rolling lobe air spring. Aiming at the prediction difficulties of structural parameters of the rolling lobe air spring with the composite curved contour piston and the modeling complexity of the hysteretic mechanical characteristic of rubber bellows under variable pressure conditions, the geometrical method is applied to derive the structural parameters models of the rolling lobe air spring with the composite curved contour piston. A new pressure factor is introduced and the Coulomb frictional pressure perturbation model and the fractional derivative Kelvin-Voigt pressure perturbation model are reconstructed to accurately describe the hysteretic mechanical characteristic of rubber bellows under variable pressure conditions. A unified pressure equation is constructed to characterize the evolution of model parameters under variable pressure conditions. Furthermore, a hysteretic mechanical characteristic pressure perturbation model (abbreviated as HMCPP model) of rubber bellows under variable pressure conditions is put forward. Finally, a unified stiffness model of the rolling lobe air spring including prediction models of nonlinear structural parameters and a HMCPP model of rubber bellows is built. Taking a certain type of rolling lobe air spring as the test sample A, the structural parameters tests and static/dynamic characteristic tests of sample A are carried out based on the MTS852.05 test bench, which verified the accuracy of the unified stiffness model of the rolling lobe air spring. The research results provide theoretical support for the mechanical characteristic matching and air pressure precise control of the rolling lobe air spring under variable pressure conditions.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1177/09544070231217565
Yifan Zhu, Fengxiang Xu, Xianglin Deng, Xiaoqiang Niu, Zhen Zou
Lightweight design is universally recognized as a critical criterion for many engineering problems. In addition to the well-developed topology optimization (TO) method, structural bionics is also considered an effective approach to developing innovative structure designs with lightweight. In the process of natural evolution, bamboo has developed a unique hollow structure with ingenious mechanical properties. Inspired by these characteristics, this paper selected bamboo as a bionic prototype to carry out bionic structure optimization of guide arm. First, the initial guide arm was modeled and simulated for its mechanical behavior. Secondly, similarity analysis between bamboo and guide arm was performed from three aspects, and the parametric bionic guide arm model was established step by step. Then, the key parameters affecting the performance of the bionic guide arm were verified by the parameter sensitivity analysis method. The multi-objective optimization was carried out with the minimum of the total mass and the maximum deformation of guide arm as the optimization objectives. The optimal solution of Pareto solution set was determined by multi-objective decision methods of the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) and Gray Relational Analysis (GRA). Finally, finite element (FE) method was used to make a comparison between the initial model and the optimal bionic model in terms of mechanical performance. According to the results, under the premise of the mass of the optimized bionic model decreased by 17.44%, the maximum deformation was decreased by 9.24%, the equivalent stress was decreased by 17.33%, and the first-order frequency was increased by 22.92%. Comparison results showed that the proposed bionic model provided the best lightweight solution for guide arm. This study reveals that structural bionics provides a new solution for the lightweight design of guide arm and similar beam structural components.
{"title":"Bionic topology optimization design and multi-objective optimization of guide arm","authors":"Yifan Zhu, Fengxiang Xu, Xianglin Deng, Xiaoqiang Niu, Zhen Zou","doi":"10.1177/09544070231217565","DOIUrl":"https://doi.org/10.1177/09544070231217565","url":null,"abstract":"Lightweight design is universally recognized as a critical criterion for many engineering problems. In addition to the well-developed topology optimization (TO) method, structural bionics is also considered an effective approach to developing innovative structure designs with lightweight. In the process of natural evolution, bamboo has developed a unique hollow structure with ingenious mechanical properties. Inspired by these characteristics, this paper selected bamboo as a bionic prototype to carry out bionic structure optimization of guide arm. First, the initial guide arm was modeled and simulated for its mechanical behavior. Secondly, similarity analysis between bamboo and guide arm was performed from three aspects, and the parametric bionic guide arm model was established step by step. Then, the key parameters affecting the performance of the bionic guide arm were verified by the parameter sensitivity analysis method. The multi-objective optimization was carried out with the minimum of the total mass and the maximum deformation of guide arm as the optimization objectives. The optimal solution of Pareto solution set was determined by multi-objective decision methods of the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) and Gray Relational Analysis (GRA). Finally, finite element (FE) method was used to make a comparison between the initial model and the optimal bionic model in terms of mechanical performance. According to the results, under the premise of the mass of the optimized bionic model decreased by 17.44%, the maximum deformation was decreased by 9.24%, the equivalent stress was decreased by 17.33%, and the first-order frequency was increased by 22.92%. Comparison results showed that the proposed bionic model provided the best lightweight solution for guide arm. This study reveals that structural bionics provides a new solution for the lightweight design of guide arm and similar beam structural components.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1177/09544070231209079
N. Hung, Ocktaeck Lim
Operation of a free piston linear engine is modeled based on the combination of three mathematical models, including a piston dynamic model, a linear alternator model and a thermodynamic model. The simulated in-cylinder pressure, piston velocity, and electric power output are compared with the corresponding experimental results to validate the models mentioned above. The influences of the design parameters, including cylinder dimension ( Le), number of coil turns ( N), and air gap ( g) between the translator and stator, on the dynamic performance, in-cylinder pressure and electric power generation of the free piston linear engine are studied. The study results show that the reduction of Le has a benefit for improving the piston dynamic performance and output electric power, however it also reduced the cylinder pressure. The increase of number of coil turns N results in the reduction of the peak piston velocity, displacement, acceleration, and pressure in the cylinder, however, it increases the output electric power of the free piston linear engine. The peak piston velocity, displacement, acceleration, and pressure in the cylinder are considerably decreased when g is reduced. However, the reduction of g has a benefit to improve the output electric power of the free piston linear engine. The energy conversion efficiency can be maximized when g and Le are reduced, and N is increased.
自由活塞线性发动机的运行模型是基于三个数学模型的组合，包括活塞动态模型、线性交流发电机模型和热力学模型。模拟的气缸内压力、活塞速度和电力输出与相应的实验结果进行了比较，以验证上述模型。研究了气缸尺寸（Le）、线圈匝数（N）和定子与译子之间的气隙（g）等设计参数对自由活塞直线发动机的动态性能、缸内压力和发电量的影响。研究结果表明，减少 Le 对改善活塞动态性能和输出电功率有好处，但同时也降低了气缸压力。增加线圈匝数 N 会导致活塞峰值速度、位移、加速度和气缸压力降低，但会增加自由活塞直线发动机的输出电功率。当 g 减小时，气缸中的活塞峰值速度、位移、加速度和压力都会大大降低。然而，g 值的减小有利于提高自由活塞式直线发动机的输出功率。当 g 和 Le 减小，N 增大时，能量转换效率可达到最大。
{"title":"The effects of design parameters on the dynamic performance, in-cylinder pressure and electrical power generation of a free piston linear engine","authors":"N. Hung, Ocktaeck Lim","doi":"10.1177/09544070231209079","DOIUrl":"https://doi.org/10.1177/09544070231209079","url":null,"abstract":"Operation of a free piston linear engine is modeled based on the combination of three mathematical models, including a piston dynamic model, a linear alternator model and a thermodynamic model. The simulated in-cylinder pressure, piston velocity, and electric power output are compared with the corresponding experimental results to validate the models mentioned above. The influences of the design parameters, including cylinder dimension ( Le), number of coil turns ( N), and air gap ( g) between the translator and stator, on the dynamic performance, in-cylinder pressure and electric power generation of the free piston linear engine are studied. The study results show that the reduction of Le has a benefit for improving the piston dynamic performance and output electric power, however it also reduced the cylinder pressure. The increase of number of coil turns N results in the reduction of the peak piston velocity, displacement, acceleration, and pressure in the cylinder, however, it increases the output electric power of the free piston linear engine. The peak piston velocity, displacement, acceleration, and pressure in the cylinder are considerably decreased when g is reduced. However, the reduction of g has a benefit to improve the output electric power of the free piston linear engine. The energy conversion efficiency can be maximized when g and Le are reduced, and N is increased.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139383767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite the rapid advancement in the field of autonomous driving vehicles, developing a safe and sensible decision-making system remains a challenging problem. The driving decision-making module is one of the most essential sections of the entire autonomous driving system, and the decision generated from it can significantly impinge the lives and property of passengers. Complicated interactions among traffic participants have the most profound impact on the decision-making process, yet the interactions are often simplified or overlooked due to their complexity and implicit nature. To address this issue, this work proposes an Edge-Enhanced Graph Attention Reinforcement Learning (EGARL) framework that aims to make rational driving decisions by comprehensively modeling the interactions among agents. EGARL comprises three core components: a graphical representation of the traffic scenario that covers both topological and interactive information; an Edge-enhanced Graph Attention Network (E-GAT) that utilizes the graphical representation to extract interactive features by comprehensively considering nodes and edges of the graph; and a deep reinforcement learning method that generates driving decisions based on the current state and features extracted from E-GAT. Experimental results demonstrate the satisfying performance of EGARL. Our proposed framework can contribute to the development of intelligent transportation systems, enhancing the safety and efficiency of driving.
{"title":"Edge-enhanced Graph Attention Network for driving decision-making of autonomous vehicles via Deep Reinforcement Learning","authors":"Yuchuan Qiang, Xiaolan Wang, Xintian Liu, Yansong Wang, Weiwei Zhang","doi":"10.1177/09544070231217762","DOIUrl":"https://doi.org/10.1177/09544070231217762","url":null,"abstract":"Despite the rapid advancement in the field of autonomous driving vehicles, developing a safe and sensible decision-making system remains a challenging problem. The driving decision-making module is one of the most essential sections of the entire autonomous driving system, and the decision generated from it can significantly impinge the lives and property of passengers. Complicated interactions among traffic participants have the most profound impact on the decision-making process, yet the interactions are often simplified or overlooked due to their complexity and implicit nature. To address this issue, this work proposes an Edge-Enhanced Graph Attention Reinforcement Learning (EGARL) framework that aims to make rational driving decisions by comprehensively modeling the interactions among agents. EGARL comprises three core components: a graphical representation of the traffic scenario that covers both topological and interactive information; an Edge-enhanced Graph Attention Network (E-GAT) that utilizes the graphical representation to extract interactive features by comprehensively considering nodes and edges of the graph; and a deep reinforcement learning method that generates driving decisions based on the current state and features extracted from E-GAT. Experimental results demonstrate the satisfying performance of EGARL. Our proposed framework can contribute to the development of intelligent transportation systems, enhancing the safety and efficiency of driving.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1177/09544070231219727
Safak Akgunlu, Onur Özcan, Aykut Bacak, Alisan Gonul, Tolga Taner, A. S. Dalkılıç
This study is about the fog on the windshields of passenger buses because it makes it hard for drivers to see, which is dangerous. The goal of the research is to come up with an effective way to spread the produced mist. According to the study, the air duct design, which is connected to the car’s defroster and defrosting system by Kraft hoses, has to be upgraded. The analysis identifies areas in which the current air duct design might be enhanced and then makes design modifications to create a superior design. By conducting climatic chamber experiments on a vehicle equipped with the first air duct design and tracking the actual air velocity values at the nozzle tips, the success of the new technique is assessed. The boundary conditions for the analysis are the observed values. The study involves the utilization of a commercially available software package to conduct investigations on both the original and modified air duct designs. The software package employs a k-ε turbulence model that is known to produce reliable results. The data demonstrate that the adjustments made in light of the comparison produced beneficial effects. The maximum air velocities were increased by 23%, while the pressure loss values of the left and right fans were reduced by 2.5% and 2.9%, respectively, due to the modification of the air duct. Significant energy was saved because of the decrease in fan pressure loss, which led to decreases in the power consumption of the left and right fans of 4.2% and 4.7%, respectively. This comparison shows that the newly built air ducts actually increased the flow rate at the system’s fan outlets by 40%.
{"title":"Novel air duct designs to estimate the windshield demisting issue for a commercial vehicle","authors":"Safak Akgunlu, Onur Özcan, Aykut Bacak, Alisan Gonul, Tolga Taner, A. S. Dalkılıç","doi":"10.1177/09544070231219727","DOIUrl":"https://doi.org/10.1177/09544070231219727","url":null,"abstract":"This study is about the fog on the windshields of passenger buses because it makes it hard for drivers to see, which is dangerous. The goal of the research is to come up with an effective way to spread the produced mist. According to the study, the air duct design, which is connected to the car’s defroster and defrosting system by Kraft hoses, has to be upgraded. The analysis identifies areas in which the current air duct design might be enhanced and then makes design modifications to create a superior design. By conducting climatic chamber experiments on a vehicle equipped with the first air duct design and tracking the actual air velocity values at the nozzle tips, the success of the new technique is assessed. The boundary conditions for the analysis are the observed values. The study involves the utilization of a commercially available software package to conduct investigations on both the original and modified air duct designs. The software package employs a k-ε turbulence model that is known to produce reliable results. The data demonstrate that the adjustments made in light of the comparison produced beneficial effects. The maximum air velocities were increased by 23%, while the pressure loss values of the left and right fans were reduced by 2.5% and 2.9%, respectively, due to the modification of the air duct. Significant energy was saved because of the decrease in fan pressure loss, which led to decreases in the power consumption of the left and right fans of 4.2% and 4.7%, respectively. This comparison shows that the newly built air ducts actually increased the flow rate at the system’s fan outlets by 40%.","PeriodicalId":509770,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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