【摘要】 基于Abaqus软件,建立闸瓦-车轮-轨道三维有限元模型,设置车轮钢材料的接触属性和材料属性,对重载列车紧急制动过程进行热力耦合仿真;基于损伤参量的疲劳裂纹萌生寿命预测模型,分析重载列车整个紧急制动过程中车轮踏面瞬态温度分布、径向和切向应力分布以及弹性和塑性应变分布,并通过计算车轮踏面损伤参量判断疲劳裂纹萌生位置,预测不同轴重和不同闸瓦压力对车轮踏面疲劳裂纹萌生寿命的影响。结果表明:重载列车紧急制动时,车轮踏面上制动温度越高则相应热应力、热应变也越大,尤其当踏面最高温度超过100℃时,热负荷对裂纹萌生的影响更加显著;车轮踏面上裂纹萌生更多的是由剪应力和剪应变引起,轮轨接触斑内是最先萌生裂纹的区域;轴重为30 t、闸瓦压力为21 kN、初速度为100 km·h^-1时损伤参量最大为3.801 1,最大循环制动次数仅有236次。更多还原

【Abstract】 Based on the Abaqus software, a three-dimensional finite element model of brake shoe-wheel-track was established with setting the contact properties and material properties of the wheel steel material, and the thermal-mechanical coupling simulation of the emergency braking process of the heavy haul train was conducted. Based on the fatigue crack initiation life prediction model of damage parameters, the transient temperature distribution, radial and tangential stress distribution, and elastic and plastic strain distribution of the wheel tread during the entire emergency braking process of the heavy haul train were analyzed, and the fatigue crack initiation position was judged by calculating the damage parameters of the wheel tread. The influence of different axle loads and different brake shoe pressures on the fatigue crack initiation life of the wheel tread was predicted. The results show that the higher the braking temperature on the wheel tread, the greater the corresponding thermal stress and thermal strain when a heavy haul train is under an emergency braking,especially when the maximum temperature of the tread exceeds 100 ℃, the influence of thermal load on crack initiation is more significant. The initiation of cracks on the wheel tread is mostly caused by the shear stress and the shear strain, and the first crack initiation area is in the wheel-rail contact spot. The maximum damage parameter is 3. 801 1 and the maximum number of cyclic braking is only 236 with the axle load of 30 t, the brake shoe pressure of 21 kN and the initial speed of 100 km·h^-1.更多还原