Wiper tools are revered for their capacity to simultaneously achieve high-quality and high-efficient machining.Nonetheless,the cutting mechanism of wiper tools remains unclear,and the cutting force prediction model of...Wiper tools are revered for their capacity to simultaneously achieve high-quality and high-efficient machining.Nonetheless,the cutting mechanism of wiper tools remains unclear,and the cutting force prediction model of wiper tools has not been reported,leading to severe wear of the bottom wiper edge and unstable cutting in machining processes.In this study,the cutting mechanism of wiper tools is systematically analyzed,and the mechanistic cutting force model considering the wiper edge cutting effect was established.The cutting force coefficients were calibrated by the cutting force separation method,which can quickly calibrate the cutting force coefficients for the flank cutting region dominated by the shear effect,the bottom cutting region dominated by the shear effect,and the bottom wiper region dominated by plough effect.Compared with measured cutting forces,the maximum average absolute errors in the predicted forces are 9.2%,7.6%,and 9.3%in the x,y,and z directions,respectively.Furthermore,the feed rate and the length of the wiper edge were primary determinants of the bottom-edge cutting forces.This study provides theoretical guidance and technical support for the wear mechanism and design of wiper tools.展开更多
Fracture occurred in wiper arm. Through the macro and micro analysis of the wiper arm fracture, chemical composition analysis, metallographic structure analysis, hardness analysis, macrostructure analysis, SEM analysi...Fracture occurred in wiper arm. Through the macro and micro analysis of the wiper arm fracture, chemical composition analysis, metallographic structure analysis, hardness analysis, macrostructure analysis, SEM analysis and so on, the cause of fracture of wiper arm were analyzed. The results show that the high hardness and the large residual stress are the main reasons for the cracking of the wiper arm due to the coincidence between the steel pipe forming weld and the wiper arm forming weld, and the improvement measures are proposed.展开更多
电动汽车动力系统噪声降低,导致雨刮反转引起的响度和尖锐度相矛盾问题更加突出,多目标优化方法有助于指导多频带协同主动控制,提升雨刮风窗系统声品质。通过实车噪声测试试验采集,分析雨刮运动过程中的噪声数据。基于各特征频带幅值与...电动汽车动力系统噪声降低,导致雨刮反转引起的响度和尖锐度相矛盾问题更加突出,多目标优化方法有助于指导多频带协同主动控制,提升雨刮风窗系统声品质。通过实车噪声测试试验采集,分析雨刮运动过程中的噪声数据。基于各特征频带幅值与响度和尖锐度的直接映射关系构建多目标优化公式。敏感性分析确定一组影响响度和尖锐度变化最大的敏感频带,通过多目标遗传算法NSGA-Ⅱ求解得到响度和尖锐度综合最优时对应的敏感频带幅值,通过基于滤波残差最小均方算法(filtered-error least mean square algorithm,FELMS)自适应滤波器的ANE算法进行响度和尖锐度的主动控制仿真,验证最优解的可行性。结果表明,响度降低15.4%,尖锐度降低18%,响度达到94%最优解效果,尖锐度达到87%最优解效果,声品质得到改善。展开更多
针对汽车电路故障检测实训课程中存在的问题,以汽车雨刮电路为对象,开发了基于混合架构的汽车雨刮电路虚拟仿真实训系统。介绍了汽车雨刮电路故障检测实训的基本内容,论述了系统总体架构的设计方案,采用C/S+B/S混合体系架构方式对系统...针对汽车电路故障检测实训课程中存在的问题,以汽车雨刮电路为对象,开发了基于混合架构的汽车雨刮电路虚拟仿真实训系统。介绍了汽车雨刮电路故障检测实训的基本内容,论述了系统总体架构的设计方案,采用C/S+B/S混合体系架构方式对系统进行设计,包括系统人机交互方案、电压表虚拟测量方案与故障检测过程评判方案等。基于上述技术方案,以VS 2012(C#)为开发平台,以SQL Server 2010为数据库,设计并开发了汽车雨刮电路故障检测虚拟仿真实训系统。目前该系统实际运行效果良好。展开更多
This paper studies the structural response of high-speed train wipers under the combined action of complex flow fields and scraping actions.The stress concentration areas are determined through simulation analysis,and...This paper studies the structural response of high-speed train wipers under the combined action of complex flow fields and scraping actions.The stress concentration areas are determined through simulation analysis,and the stress and aerodynamic load measurement points are reasonably arranged accordingly.The actual measurement is carried out in combination with the operating conditions of the existing lines.The stress variations and spectral characteristics of the train under different speed levels(80,160,180,200 km/h),tunnel entry and exit,and scraper action conditions were compared and analyzed.The stress amplification factors under tunnel intersection and scraper action were obtained,providing boundary conditions for the design of wipers for highspeed s.The research results show that the maximum stress of the wiper structure obtained through simulation calculation is concentrated at the connection of the wiper arm.Structural stress increases with the rise of speed grade.The stress increases by 1.11 times when the tunnel meets.When the scraper operates,the stress on the scraper arm increases by 4.1–7.6 times.Due to the broadband excitation effect of the aerodynamic load,the spectral energy of the structure is relatively high at the natural frequency,which excites the natural mode of the wiper.展开更多
基金Supported by National Key Research and Development Program of China(Grant No.2018YFA0702900)National Natural Science Foundation of China(Grant Nos.52075076,U1908231)。
文摘Wiper tools are revered for their capacity to simultaneously achieve high-quality and high-efficient machining.Nonetheless,the cutting mechanism of wiper tools remains unclear,and the cutting force prediction model of wiper tools has not been reported,leading to severe wear of the bottom wiper edge and unstable cutting in machining processes.In this study,the cutting mechanism of wiper tools is systematically analyzed,and the mechanistic cutting force model considering the wiper edge cutting effect was established.The cutting force coefficients were calibrated by the cutting force separation method,which can quickly calibrate the cutting force coefficients for the flank cutting region dominated by the shear effect,the bottom cutting region dominated by the shear effect,and the bottom wiper region dominated by plough effect.Compared with measured cutting forces,the maximum average absolute errors in the predicted forces are 9.2%,7.6%,and 9.3%in the x,y,and z directions,respectively.Furthermore,the feed rate and the length of the wiper edge were primary determinants of the bottom-edge cutting forces.This study provides theoretical guidance and technical support for the wear mechanism and design of wiper tools.
文摘Fracture occurred in wiper arm. Through the macro and micro analysis of the wiper arm fracture, chemical composition analysis, metallographic structure analysis, hardness analysis, macrostructure analysis, SEM analysis and so on, the cause of fracture of wiper arm were analyzed. The results show that the high hardness and the large residual stress are the main reasons for the cracking of the wiper arm due to the coincidence between the steel pipe forming weld and the wiper arm forming weld, and the improvement measures are proposed.
文摘电动汽车动力系统噪声降低,导致雨刮反转引起的响度和尖锐度相矛盾问题更加突出,多目标优化方法有助于指导多频带协同主动控制,提升雨刮风窗系统声品质。通过实车噪声测试试验采集,分析雨刮运动过程中的噪声数据。基于各特征频带幅值与响度和尖锐度的直接映射关系构建多目标优化公式。敏感性分析确定一组影响响度和尖锐度变化最大的敏感频带,通过多目标遗传算法NSGA-Ⅱ求解得到响度和尖锐度综合最优时对应的敏感频带幅值,通过基于滤波残差最小均方算法(filtered-error least mean square algorithm,FELMS)自适应滤波器的ANE算法进行响度和尖锐度的主动控制仿真,验证最优解的可行性。结果表明,响度降低15.4%,尖锐度降低18%,响度达到94%最优解效果,尖锐度达到87%最优解效果,声品质得到改善。
文摘针对汽车电路故障检测实训课程中存在的问题,以汽车雨刮电路为对象,开发了基于混合架构的汽车雨刮电路虚拟仿真实训系统。介绍了汽车雨刮电路故障检测实训的基本内容,论述了系统总体架构的设计方案,采用C/S+B/S混合体系架构方式对系统进行设计,包括系统人机交互方案、电压表虚拟测量方案与故障检测过程评判方案等。基于上述技术方案,以VS 2012(C#)为开发平台,以SQL Server 2010为数据库,设计并开发了汽车雨刮电路故障检测虚拟仿真实训系统。目前该系统实际运行效果良好。
文摘This paper studies the structural response of high-speed train wipers under the combined action of complex flow fields and scraping actions.The stress concentration areas are determined through simulation analysis,and the stress and aerodynamic load measurement points are reasonably arranged accordingly.The actual measurement is carried out in combination with the operating conditions of the existing lines.The stress variations and spectral characteristics of the train under different speed levels(80,160,180,200 km/h),tunnel entry and exit,and scraper action conditions were compared and analyzed.The stress amplification factors under tunnel intersection and scraper action were obtained,providing boundary conditions for the design of wipers for highspeed s.The research results show that the maximum stress of the wiper structure obtained through simulation calculation is concentrated at the connection of the wiper arm.Structural stress increases with the rise of speed grade.The stress increases by 1.11 times when the tunnel meets.When the scraper operates,the stress on the scraper arm increases by 4.1–7.6 times.Due to the broadband excitation effect of the aerodynamic load,the spectral energy of the structure is relatively high at the natural frequency,which excites the natural mode of the wiper.
