【作者】 刘洋；

【导师】 郑松林；

【作者基本信息】 上海理工大学 ， 车辆工程， 2014， 硕士

【摘要】 随着汽车工业的发展和相应法规的完善,各国对汽车的安全性能提出了更高的要求,耐久性试验成为轿车研发最为关键的环节之一。目前,国内的耐久性试验主要集中在用户道路试验和试车场道路试验等室外试验上,这一过程不仅周期较长而且成本较高。随着计算机仿真技术的快速发展,将CAE技术运用于汽车零部件的耐久性试验中逐渐成为主流趋势,借助虚拟仿真技术在开发初期及早发现存在的问题并加以改进,能有效缩短试验周期,减少试验费用,优化研发流程。本文以某车型的前副车架试验台系统为研究对象,建立了前副车架试验台系统的有限元模型,包括前副车架试件和六立柱夹具两部分,并对系统进行静态和动态精度验证,证明模型具有较高的精度。建立了一套轿车前副车架的疲劳耐久性试验仿真分析流程。该流程通过两种分析软件的综合应用,实现了包含静强度分析、模态分析、疲劳危险点位置的预测、虚拟应变片载荷采集、危险点损伤计算和寿命评估等技术环节的连续运用。经台架试验验证,流程涉及的分析计算具有较高的准确性,这套方法能帮助研发人员摆脱了物理样机试验的约束,在设计初期及时发现试件存在的问题,节约了试验成本,有推广应用价值。借助于系统的有限元模型,从夹具层面分析影响台架试验的多种关键因素,包括试件-夹具的连接刚度、试件-夹具连接点处的动刚度、夹具的固有频率、夹具的疲劳强度特性等,确定出了实际台架试验中夹具容易疲劳失效的原因,提出了夹具优化设计方案。本文完成的工作和建立的仿真分析流程,可为汽车大型结构件疲劳耐久试验的台架方案设计与制造提供技术指导,确保试验过程和结果的正确性。更多还原

【Abstract】 With the development of automobile industry and the perfect of laws and regulations,each country now is putting forward higher and higher requirement for the safety of vehicle.Durability and anti-fatigue properties of automotive components has been paid more and more attention,also durability test has been the most crucial link during the process of car development.Durability and anti-fatigue properties is an important indication for the quality of the vehicle,and it’s also the premise of subsequent structure optimization.At present,domestic durability test mainly focus on the outdoor test with long time and much cost like the customer road test and the field road test.Because of the rapid development of IT computing technology,CAE has gradually become the main trend using in durability test for automobile components.With the help of virtual simulation technology,engineers can understand and evaluate the whole fatigue durability working characteristics of the product as soon as possible,then make corresponding improvement and optimization.In this paper,we make the front sub-frame as the research component.First of all,set up the finite element model of the test bench including the sub-frame component and the six-column fixture,and verify the accuracy of the CAE model from static and dynamic aspects,according to the static stress contour result and strain rain-flow analysis result,we can find that the finite element model of sub-frame test bench system has a high accuracy.It can make a good preparation for the subsequent analysis,then do the static stress analysis and virtual fatigue analysis,gather the virtual strain-time signal and calculate the damage of the predicted dangerous location,so that we will have a comprehensive understanding about the component’ fatigue characteristics.About the phenomenon that fixture fatigue failure occur often during the indoor bench test,we explored the reason with simulation method by changing the size of section to change the stiffness of fixture,By doing so we can know well about the overall influence of the fixture stiffness to the test bench system,find out the optimal designing size of fixture section.The results show that the fatigue durability simulation technology can effectively help designers found the problem of products in the early designing stage,get rid of the test constraints of physical prototype.This method can reliably simulate the whole working characteristic of the test bench system,which can effectively reduce the time of experiment,save the total cost and improve the competitiveness of products.The method of virtual fatigue analysis process summed up in this paper can be used for other automobile component just like front sub-frame.The simulation result is in a higher degree consistent with the bench test results can ensure the accurate designing for these components.更多还原