摘要
汽车制动盘的工作温度高、易产生热疲劳,其性能直接影响行车安全,对高温下制动盘的热疲劳裂纹萌生寿命的研究十分必要。首先研究取自汽车制动盘上的灰铸铁HT200试样在500℃下单调拉伸与压缩的性能,对应力—应变曲线进行分析,得到其力学性能参数;接着基于这些参数,对初始温度为400℃时的制动盘在单次紧急制动工况下进行热-结构耦合仿真分析,得到制动盘的温度场和应力场分布;最后利用应变疲劳的方法根据Miner线性累积损伤理论研究500℃下灰铸铁HT200的塑性特性对制动盘热疲劳裂纹萌生寿命的影响。研究结果表明:制动过程中的热应力远大于机械应力,是产生疲劳裂纹的主要原因;高温下制动盘材料HT200的塑性特性对制动盘热疲劳裂纹萌生寿命的影响很大,在研究制动盘裂纹萌生寿命时需考虑高温下塑性特性对寿命的影响。利用制动盘在高温制动过程中的周向应变并考虑高温下材料的塑性特性计算热疲劳裂纹萌生寿命,为制动盘热疲劳寿命的评价打下基础。
The brake disc of a vehicle often works at high temperature, and its damage caused by thermal fatigue easily takes place. So the performance of the vehicle brake disc is directly related to the safety of driving, and it is very necessary to study the thermal fatigue crack initiation life of the brake disc at high temperature. The monotonic tensile and compressive tests of gray cast iron HT200 sample for vehicle brake discs are carried out at 500℃, and the stress-strain curves are analyzed to obtain mechanical properties at 500℃;then based on these parameters, the finite element software ABAQUS is used to establish the thermal-structure coupled finite element model of the vehicle brake disc with the initial temperature of 400℃, and the temperature fields and stress fields on the brake disc for emergency braking condition are analyzed. Finally, the effect of the plastic property of HT200 on the thermal fatigue crack initiation life of the brake disc on the 500℃ is studied by using strain fatigue method according to the Miner linear cumulative damage theory. The results show that the thermal stress during braking is far greater than the mechanical stress, which is the main cause of fatigue cracks;the plastic property of gray cast iron HT200 of brake disc has a great influence on the thermal fatigue crack initiation life of the brake disc. The effect of plastic property on the life of the brake disc should be introduced in the study of the crack initiation life of the brake disc. The thermal fatigue crack initiation life of brake disc is calculated by using the circumferential strain of brake disc during braking at high temperature and considering the plastic properties of material at high temperature, which lays a foundation for the evaluation of thermal fatigue life of brake disc.
作者
刘禹
单颖春
刘献栋
何田
LIU Yu;SHAN Yingchun;LIU Xiandong;HE Tian(School of Transportation Science and Engineering, Beihang University, Beijing 100191;Beijing Key Laboratory for High-efficient Power Transmission and System Control of New Energy Resource Vehicle, Beihang University, Beijing 100191)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2019年第8期97-105,共9页
Journal of Mechanical Engineering
关键词
灰铸铁HT200
拉伸/压缩试验
热-结构耦合
热疲劳裂纹萌生寿命
gray cast iron HT200
tensile and compressive test
thermal-structure coupled
thermal fatigue crack initiation life
作者简介
刘禹,男,1993年出生。主要研究方向为汽车结构强度与疲劳。E-mail:yuliu@buaa.edu.cn;通讯作者:刘献栋(通信作者),男,1966年出生,博士,教授,博士研究生导师。主要研究方向为汽车振动与噪声控制、汽车结构强度与疲劳。E-mail:liuxiandong@buaa.edu.cn.
