Table of Content

25 March 2021, Volume 43 Issue 3 Previous Issue    Next Issue

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Kinematics Optimization of Double Wishbone Front Suspension for In⁃wheel Motor⁃Driven Electric Vehicles Junnian Wang,Peng Liu,Fang Yang,Liqiang Jin,Tiejun Fu 2021, 43 (3):  305-312.  doi: 10.19562/j.chinasae.qcgc.2021.03.001 Abstract ( 439 )   HTML ( 22 )   PDF (1962KB) ( 638 )   Save In the retrofit of the in?wheel motor?driven electric vehicle based on the chassis platform of traditional vehicle, the placement of hub?motors will result in the coordination change of suspension hard?points, severely affecting the kinematic characteristics of suspension. Therefore, a design optimization of the retrofitted in?wheel motor?driven electric vehicle is required. With the kinematic characteristics of the double wishbone front suspension in a conventional vehicle chassis platform as optimization objectives, a two?step optimization scheme is proposed according to the results of parameter sensibility analysis, i.e. the optimization of kingpin positioning parameters is performed first, then that of camber and toe proceeds. The optimization solution set of suspension parameters obtained by using ISIGHT software and the global non?normalized multi?objective genetic optimization algorithm NSGA?II is validated under the ADAMS/Car platform. The results show that the optimized suspension kinematic characteristics are improved significantly, being basically consistent with the K characteristics of original vehicle, demonstrating the feasibility of optimization scheme adopted and assuring the handling and stability of retrofitted electric vehicle not greatly affected by the placement of hub?motors. Figures and Tables | References | Related Articles | Metrics

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Energy Management Strategy of Plug⁃in Hybrid Electric Vehicle with Engine Start and Stop Optimization Long Chen,Zhixing Chen,Xing Xu,Feng Wang,Yingfeng Cai,Tao Zhang 2021, 43 (3):  313-322.  doi: 10.19562/j.chinasae.qcgc.2021.03.002 Abstract ( 305 )   HTML ( 10 )   PDF (5049KB) ( 525 )   Save In order to solve the problem of fuel consumption increase of the engine in a new type of dual motors planetary coupling PHEV under start?and?stop and idle conditions， based on the minimum energy management strategy of equivalent fuel consumption， an optimization module of engine start?and?stop control is added to improve the fuel economy of the vehicle. The whole vehicle dynamics and transmission model is established， and the engine start?and?stop optimization control module is added to redistribute the optimal target torque distribution of the engine and motor output by the ECMS energy management strategy， which is then output to the engine and motor controller to control their working state. Particle swarm optimization algorithm is used to optimize the key time parameters which affect the frequency in the optimal control of start and stop. The simulation results show that the proposed energy management optimization strategy can effectively control the start?and?stop or idle state of the engine， reduce the start?and?stop frequency of the engine， and reduce fuel consumption， which verifies that the proposed energy management optimization strategy can further optimize the vehicle fuel economy. Figures and Tables | References | Related Articles | Metrics

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column:Vehicle Parallel Parking Path Planning Based on Adaptive Neuro⁃fuzzy Inference System Jiaxu Zhang,Chen Wang,Chong Guo,Fei Teng,Dongran Li 2021, 43 (3):  323-329.  doi: 10.19562/j.chinasae.qcgc.2021.03.003 Abstract ( 230 )   HTML ( 12 )   PDF (1608KB) ( 351 )   Save Aiming at the common parallel parking scene， a novel parallel parking path planning method for vehicle is proposed based on adaptive neuro?fuzzy inference system. With the parking path obtained from parallel parking path planning based on optimization algorithm as training sample， Python script is used to build the automated training framework with adaptive genetic algorithm and quasi?Newton algorithm as its core for enabling the adaptive neuro?fuzzy inference system automatically trained can not only inherit the merits of wider application scope of parallel parking path planning method based on optimization algorithm， but also effectively get rid of enormous computation efforts. The feasibility and effectiveness of the proposed method are verified by simulation， and the results show that the adaptive neuro?fuzzy inference system automatically trained can quickly plan the feasible parallel parking path based on the initial parking posture of vehicle and parking space information. Figures and Tables | References | Related Articles | Metrics

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Study on Large Eddy Simulation of Diesel Supercritical Spray Wenjin Qin,Jiafu Wang,Xiaohai Li,Hao Liu 2021, 43 (3):  330-336.  doi: 10.19562/j.chinasae.qcgc.2021.03.004 Abstract ( 174 )   HTML ( 5 )   PDF (2392KB) ( 209 )   Save With the constant increase of temperature and pressure in the combustion chamber of modern internal combustion engines， liquid fuel is often in the supercritical state， and compared with the subcritical state， its spray jet behavior characteristics have undergone great changes. In this study， the large eddy simulation method is used to numerically calculate the single?component and multi?component diesel surrogate fuel spray jets in supercritical environment， and the difference between different gas state equations in predicting the behavior of supercritical fuel injection of diesel fuel is compared. It is found that the simulation results of PR gas state equation on n?heptane mass fraction distribution are closer to the experimental values， with better results than other state equations. It is also found that the multi?component diesel characterized fuel （n?heptane mass fraction 80%， toluene mass fraction 10%， cyclohexane mass fraction 10%） used in this study can better reflect the characteristics of real diesel spray jet in supercritical environment. Figures and Tables | References | Related Articles | Metrics

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Multi⁃objective Optimization Design of Key Structural Parameters of Spiral Section of Helical Inlet Wei Zhang,Libing Xie,Zhaohui Chen,Mayi Zhou,Yong Chen,Jiwen Fan,Li Tao 2021, 43 (3):  337-344.  doi: 10.19562/j.chinasae.qcgc.2021.03.005 Abstract ( 207 )   HTML ( 6 )   PDF (3538KB) ( 252 )   Save Using steady?state air?flow experiments and CFD steady?state simulation， combined with the multi?objective optimization design method， the influence of four key structural parameters including minimum cross?sectional area of helical section， the inner radius of volute， the outer radius of volute and the height of the spiral chamber on the inlet flow characteristics of single helical intake port of YN diesel engine is studied. The results show that the approximate mathematical model obtained by regression analysis can realize the positive quantitative research of inlet structure parameters and inlet performance. The multi?objective optimization design of the structural parameters of the original intake port helical section can significantly increase the eddy current ratio （9.3%~14.34%）， with a small decrease of the flow coefficient （0~3.98%）. Figures and Tables | References | Related Articles | Metrics

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Study on Aging Effect of Aging Cycle on Three⁃way Catalytic Converter Sheng Su,Pan Hou,Yitu Lai,Lü Tao,Xin Wang,Yunshan Ge,Lü Liqun 2021, 43 (3):  345-349.  doi: 10.19562/j.chinasae.qcgc.2021.03.006 Abstract ( 213 )   HTML ( 11 )   PDF (1662KB) ( 243 )   Save To study the impact of different driving cycles on thermal aging of vehicles' three way catalytic converter （TWC）， a gasoline vehicle and a hybrid vehicle with the same engine which meet China VI emission standard are selected to carry out approved mileage accumulation （AMA）， standard road cycle （SRC）， world-wide harmonized light duty driving test cycle （WLTC） and real driving emission test （RDE）. Meanwhile， the operating parameters and TWC bed temperature are collected by established data collection system. Based on Arrhenius mechanism， the thermal aging intensity after durability tests with different aging cycles of 160，000 km is quantified as thermal damage， and the equivalent real driving mileage in different aging cycles are converted with the RDE cycle as the reference. The results show that， the 160，000 km thermal aging intensity of hybrid vehicle's TWC is lower than that of gasoline vehicle's TWC under the same aging cycle. The thermal aging intensity caused by AMA and SRC cycles is significantly higher than that caused by WLTC and RDE cycles under the same driving mileage. The thermal aging effect on TWC of 160，000 kilometers on AMA cycle and SRC cycle of pure gasoline vehicle is equivalent to that of 518，400 and 603，000 kilometers on real road respectively； and the thermal aging effect on TWC of 160，000 kilometers on AMA cycle and SRC cycle of hybrid electric vehicle is equivalent to that of 304，400 and 292，100 kilometers on real road， respectively. Figures and Tables | References | Related Articles | Metrics

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Study on the Effects of Exhaust Temperature， Exhaust Flow Rate and Altitude on NOx Conversion Rate and NH3 Slip of SCR System Yuhua Bi,Xuexuan Nie,Shaohua Liu,Ben Xiao,Peng Wang,Lizhong Shen,Yiyuan Peng 2021, 43 (3):  350-357.  doi: 10.19562/j.chinasae.qcgc.2021.03.007 Abstract ( 217 )   HTML ( 6 )   PDF (3231KB) ( 243 )   Save In order to study the performance of SCR at different altitudes， the performance and emission tests on a high?pressure common?rail diesel engine meeting the national?V emission regulation are conducted under 80、90 and 100 kPa atmospheric pressures respectively to study the effects of exhaust temperature， exhaust flow rate， and altitude on NOx conversion rate and ammonia slip. The results show that under an exhaust flow rate of 350 kg/h， with the increase of exhaust temperature， the NOx conversion rate exhibits a tendency of rises first and then falls， with the maximum difference of NOx conversion rate of 43.4 percentage points at different exhaust temperatures； The ammonia slip by and large reduces with the rise in exhaust temperature， and the maximum difference of ammonia slip is 328×10-6 at different temperatures. The NOx conversion rate show a trend of rise first and then fall as the exhaust flow rate increases， with a maximum difference of NOx conversion rate of 21.5 percentage points at different exhaust flow rates when the exhaust temperature is 250 ℃； The ammonia slip increases with the increase of exhaust flow rate， and the maximum difference of ammonia slip is 90.8×10-6 at different exhaust flow rates when the exhaust temperature is 250 ℃. Under the same working conditions， the higher the altitude， the greater the NOx conversion rate and the smaller the ammonia slip， and when the atmospheric pressure lowers from 100 kPa to 80 kPa， the maximum NOx conversion rate rises by 20.1 percentage points and the maximum ammonia slip reduces by 54.6×10-6. Figures and Tables | References | Related Articles | Metrics

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Optimum Condition Selection Method and Test Verification for Objective Evaluation of Powertrain Drivability Wei Zhou,Xuexun Guo,Xiaofei Pei,Chengcai Zhang,Jun Yan,Jialei Xia 2021, 43 (3):  358-363.  doi: 10.19562/j.chinasae.qcgc.2021.03.008 Abstract ( 232 )   HTML ( 8 )   PDF (1444KB) ( 265 )   Save In view of the poor rationality in selecting the working conditions for powertrain drivability evaluation， an optimum condition selection method is proposed for powertrain drivability evaluation based on combined weight and improved TOPSIS method. Firstly， the objective evaluation indicators of drivability are analyzed according to the working principle of powertrain with the software and hardware for testing and analysis developed. Then， based on the idea of combined weighting and adopting analytic hierarchy process （AHP） and coefficient of variation （CV） methods， the subjective and objective weights are determined， and the principle of minimum relative information entropy is applied to obtaining the optimum weights of AHP?CV model. Furthermore， the improved TOPSIS method with weighted Mahalanobis distance instead of Euclidean distance is used to build the optimum selection model for vehicle drivability evaluation conditions. Finally， the static gear shifting conditions are studied as an example， and the values of weighted indicators of 10 sub?conditions are obtained， with the sub?conditions comprehensively sorted. The test results show that the proposed improved AHP?CV?TOPSIS model has good suitability in condition selection for vehicle drivability evaluation， and can reveal the degree of importance of each sub?condition for drivability evaluation， providing scientific guidance in condition selection for subjective and objective evaluations of vehicle drivability. Figures and Tables | References | Related Articles | Metrics

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Pseudo⁃spectral Method for Optimal Control of Two⁃Speed Transmission in Shift Process Xiaokun Liu,Xinxin Zhao 2021, 43 (3):  364-373.  doi: 10.19562/j.chinasae.qcgc.2021.03.009 Abstract ( 197 )   HTML ( 12 )   PDF (1281KB) ( 413 )   Save With the development of electric vehicles， multi?gear transmission can improve the efficiency of the motor under the premise of ensuring the power performance of the vehicle. In order to reduce the impact of shifting and improve ride comfort， coordinated control of the drive motor and the shift motor is required. In this paper， taking the two?speed transmission as the research object， a shift strategy based on Radau pseudo spectral method is proposed. The impact degree and sliding friction work are selected as the evaluation functions of the shifting quality of the two?speed transmission. The state variables and control variables of the system in the shifting process are approximated by interpolation polynomials， and the derivative value of interpolation polynomials is used to approximate the differential value of the state variables in the dynamic equations. The optimal control problem of shifting process is transformed into a nonlinear programming problem， which is solved by the existing nonlinear programming problem solver. Using MATLAB software to solve the shift problem of the two?speed transmission with pseudo spectral method， the optimal control trajectory of the two?speed transmission is obtained， which verifies the effectiveness and superiority of the pseudo spectral method. Figures and Tables | References | Related Articles | Metrics

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Study on Active Disturbance Rejection Control for Speed Ratio of Hydro⁃mechanical Continuously Variable Transmission Junlin Luo,Wei Wu,Shihua Yuan,Hui Liu,Xinyong Li 2021, 43 (3):  374-380.  doi: 10.19562/j.chinasae.qcgc.2021.03.010 Abstract ( 181 )   HTML ( 4 )   PDF (2097KB) ( 308 )   Save In this paper， a hydro?mechanical continuously variable transmission with single planetary row is designed， and for enhancing its speed ratio tracking control performance， an active disturbance rejection control （ADRC） algorithm with feedforward compensation is proposed to achieve the speed ratio tracking control. Firstly， a mathematical model of the system is established， the feed?forward control quantity is obtained through a theoretical analysis on the rotational speed relationship of transmission system， and the active disturbance rejection controller is adopted to apply the closed?loop control on speed ratio. Then the system simulation platform is set up， the prototype vehicle is built， and the designed active disturbance rejection speed ratio controller with feedforward compensation is verified by simulation and test. The results show that the proposed active disturbance rejection speed ratio control scheme can effectively achieve the tracking control of speed ratio. Compared with the classical PID control， ADRC has the advantages of small deviation in speed ratio， high response speed， good adaptability and strong disturbance resistance ability. Figures and Tables | References | Related Articles | Metrics

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Simulation and Experimental Study on Thermal Management System of Vehicle Fuel Cell Wenjie Zheng,Jing Yang,Linpei Zhu,Fei Xiong 2021, 43 (3):  381-386.  doi: 10.19562/j.chinasae.qcgc.2021.03.011 Abstract ( 377 )   HTML ( 26 )   PDF (1741KB) ( 537 )   Save Thermal management is an important influencing factor of the performance and life of vehicle fuel cell. Designing and modeling of fuel cell thermal management system is the key of thermal management research. Firstly， the thermal model of fuel cell is established by theoretical derivation method， and the accuracy of the model is verified by bench test. Secondly， the one?dimensional simulation model of vehicle fuel cell thermal management system is established to analyze the sensitivity of wind speed and wind temperature affecting the effluent temperature of the stack. Finally， through simulation calculation， the outlet water temperature of the stack under three typical working conditions is analyzed， which is verified by the vehicle ring model test. The results show that the proposed model of fuel cell thermal management system can accurately analyze the outlet water temperature of stack under different working conditions， which provides a reference for the analysis and optimization of fuel cell thermal management performance in vehicle development process， and has practical engineering significance for improving the thermal management level of fuel cell vehicles. Figures and Tables | References | Related Articles | Metrics

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Battery SOC Balance Control Under Idle Charging Condition Chongxiang Mo,Jian Wu,Hongzhong Qi 2021, 43 (3):  387-396.  doi: 10.19562/j.chinasae.qcgc.2021.03.012 Abstract ( 184 )   HTML ( 5 )   PDF (4899KB) ( 315 )   Save On the basis of an analysis on the battery energy stability control requirements of single motor and dual motor hybrid electric vehicles under engine idle charging condition， an active control strategy for battery SOC balance under idle charging condition is proposed， with the calculation formula for the energy control target value corresponding to each control phase is given and analyzed. Simulation and real vehicle test are conducted on the battery SOC balance control strategy under idle charging condition with a result showing that the proposed control strategy can effectively control the SOC balance of battery， and the control stability of battery active energy overcharging and over?discharging in idle charging condition is also improved. Figures and Tables | References | Related Articles | Metrics

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Experimental Study of Wind Noise on A⁃pillar and Rear⁃view Mirror in Simplified Car⁃body Models Qiliang Wang,Xin Chen,Yingchao Zhang,Xiangdong Zhang,Cansong Gu,Qingqing Guan 2021, 43 (3):  397-404.  doi: 10.19562/j.chinasae.qcgc.2021.03.013 Abstract ( 427 )   HTML ( 11 )   PDF (3961KB) ( 285 )   Save For studying the wind noise on A?pillar and rear?view mirrors， a simplified vehicle model is built. Based on aero?acoustic wind tunnel tests， five models with different styling features are designed. With A?weighted sound pressure level and articulation index as the evaluation indicators， the wind noise on the surface of side window， that in the far field and that inside the vehicle are comparatively analyzed. The results show that high?frequency noise attenuates faster in the area of A?pillar vortex， and the square A?pillar has a significant masking effect on the noise on rear?view mirror. There is a pressure level peak in the noise on rear?view mirror， and the corresponding characteristic frequency increases with the rise of wind speed. As the wind speed increases， the wind noise on the windows， that in the far field and that inside the vehicle of all models increases apparently. When yawing， the wind noise on the windows shows a tendency of falling on the windward side and rising on the leeward side in the whole frequency range. The far?field noise and the interior noise show the same trend in different frequency bands. Figures and Tables | References | Related Articles | Metrics

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Alarm Strategy for Frontal Crash Warning System Based on Driving Style Hui Jin,Haotian Li 2021, 43 (3):  405-413.  doi: 10.19562/j.chinasae.qcgc.2021.03.014 Abstract ( 397 )   HTML ( 15 )   PDF (2191KB) ( 422 )   Save With consideration of driving style, an optimized prediction model for longitudinal relative distance is designed, based on which an alarm strategy for the frontal?crash warning system is improved. The combination of quantile method and information entropy method is adopted for driving style classification to extract features in different ways, and k?means method is used to cluster sample data. Based on long short-term memory model, the encoder?decoder model is designed for prediction. All the data of above classifications are used to train the sharing parameters of model for improving its generalization ability, while the personalized parameters are trained with a higher learning rate by the corresponding data set of three driving styles. Utilizing the above?mentioned prediction models, the warning strategy for frontal crash based on European NCAP?AEB test protocol is improved, and as a result, the number of false alarms reduces from 123 to 50. Figures and Tables | References | Related Articles | Metrics

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Finite Element Analysis on Head Injury of Child Occupants in City Bus Shihai Cui,Weisheng Ma,Haiyan Li,Lijuan He,Lü Wenle 2021, 43 (3):  414-420.  doi: 10.19562/j.chinasae.qcgc.2021.03.015 Abstract ( 276 )   HTML ( 2 )   PDF (4551KB) ( 209 )   Save Based on the validated head model with detailed anatomical structure and the finite element model of child dummy body， a 6?year?old hybrid finite element human model with high computational efficiency is constructed， which is then combined with the finite element model of city bus to conduct a simulations on the head injury of children under emergency braking and frontal crash conditions with four typical seat positions the children commonly choose. The results show that under normal driving condition of city bus， the emergency braking will not cause the head injury of children. However， it may occur in the case of crash accident. Finally， the seat positions prone to head injury for children are given， and the features of head impact injury are analyzed， providing theoretical support for the safety protection of child occupants in city bus. Figures and Tables | References | Related Articles | Metrics

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Study on Lightweighting of CFRP Bumper Beam Using Entropy⁃based TOPSIS Approach Rongchao Jiang,Tao Zhang,Haixia Sun,Dawei Liu,Huanming Chen,Dengfeng Wang 2021, 43 (3):  421-428.  doi: 10.19562/j.chinasae.qcgc.2021.03.016 Abstract ( 182 )   HTML ( 8 )   PDF (2988KB) ( 291 )   Save In view of the excellent mechanical properties （light weight and high strength） of carbon fiber reinforced polymer （CFRP）， the original steel bumper beam of a passenger car is replaced by CFRP one， with its stacking sequence optimized in this paper. Firstly， the material parameters are obtained through the mechanical property tests of CFRP laminates， with its accuracy verified by three point bending simulation test. Then the thickness of CFRP bumper beam is determined based on equivalent stiffness design principle， and a low?speed collision finite element simulation is performed to compare the crashworthiness of steel and CFRP bumper beams. On this basis， with the mass， specific energy absorption， maximum intrusion and peak collision force of bumper beam as objectives， a stacking sequence optimization is conducted on CFRP bumper beam to determine the optimum stacking scheme by adopting entropy?based TOPSIS approach. The results show that the mass of CFRP bumper beam optimized is 76.82% less than original steel one， while ensuring the requirements of crashworthiness. Figures and Tables | References | Related Articles | Metrics

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Experimental Study on the Relationship Between Tire Cavity Resonance Noise and Tire Force Transmissibility Haichao Zhou,Qi Xia,Guolin Wang,Jian Yang,Shupei Zhang,Changda Li 2021, 43 (3):  429-436.  doi: 10.19562/j.chinasae.qcgc.2021.03.017 Abstract ( 296 )   HTML ( 4 )   PDF (5267KB) ( 387 )   Save In order to study the characteristics of tire cavity resonance noise and its evaluation methods， by inflating air and helium to inside the tire and pasting the non?sound?absorbing foam and different sound absorbing materials in the inner liner， an experimental study on the correlations between the characteristics of tire force transmission rate and that of cavity resonance， including tire drop noise， indoor noise on dynamometer and real vehicle road noise， are carried out. The results show that both helium filling and porous sound-absorbing material have apparent effects on the tire force transmission characteristics and the tire cavity resonance noise. Tire drop noise and indoor noise on dynamometer can effectively reflect the tire cavity resonance characteristics. The tire force transmission rate peak is well consistent with the tire cavity resonance noise peak. Accordingly it is concluded that the tire cavity resonance noise can be characterized by the tire force transmission rate. Figures and Tables | References | Related Articles | Metrics

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Numerical Simulation and Evaluation of Vehicle Rainwater Management Yingchao Zhang,Weiping Yuan,Zhenyu Zheng,Guohua Wang,Chun Shen 2021, 43 (3):  437-441.  doi: 10.19562/j.chinasae.qcgc.2021.03.018 Abstract ( 215 )   HTML ( 17 )   PDF (1860KB) ( 264 )   Save When vehicle is running on rainy days， the raindrop falling on the front side window will affect the side views and rear views of driver， causing an adverse effect on driving safety， thus the rainwater management of the front side?window is of great importance for vehicle safety. However， so far there is no unified and effective evaluation method for this issue. In view of this， the fluid film model and the Lagrangian particle model are applied to a rainwater simulation on a SUV in this paper， and an evaluation method for the rainwater management of side window based on ergonomics and particle beam trajectory technology is proposed with a corresponding analysis performed on simulation results. Figures and Tables | References | Related Articles | Metrics

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Multi⁃object Adaptive Optimization of Spot Welds with Consideration of Robustness Haisheng Song,Na Yang,Changhai Yang,Zhiyong Chen,Wenku Shi 2021, 43 (3):  442-449.  doi: 10.19562/j.chinasae.qcgc.2021.03.019 Abstract ( 183 )   HTML ( 6 )   PDF (3642KB) ( 323 )   Save Resistance spot welding is the main assembly process in body?in?white manufacturing. The number and layout of spot welds may have great effects on the dynamic and static stiffness of body?in?white， but these two effects are not always in the same direction. Therefore， in the optimization with concurrently improving both dynamic and static stiffness as the objective， an indicator， which can take into account both dynamic and static stiffness， is required， while ensuring the industrial robustness in production. In this paper， a decision?making indicator for spot weld optimization with consideration of both dynamic and static stiffness is proposed based on the strain energy of spot welds and adjacent elements. The indicator is then used to construct an efficient robustness analysis scheme， thus forming a multi?objective adaptive optimization method for spot?welds， enabling the realization of a spot?weld optimization process， with concurrent consideration of multiple performance indicators and robustness. Finally， the method is applied to the performance optimization and robustness analysis of the spot welds in the body?in?white of a light bus， with its effectiveness verified by tests. Figures and Tables | References | Related Articles | Metrics