铝合金轮毂弯曲疲劳试验的有限元模型

Finite element model of bending fatigue test of aluminumalloy wheel

在铝合金轮毂产品开发阶段,针对试压铸小批量样件来进行的弯曲疲劳试验,是必须通过的台架试验之一.为避免试验的盲目性,减少试验次数,从而降低试验成本,提高试验的可靠性,有限元数值分析技术被采用,并已成为铝合金轮毂开发的先进设计技术手段.为正确应用该技术进行虚拟台架试验,必须建立有效的计算模型.基于理论分析与应用实践,考虑螺栓预紧力影响的非线性接触,以及加载杆与轮毂的材料异同,建立了轮毂弯曲疲劳台架试验的3种有限元力学模型:加载杆与轮毂为同种材料的整体线弹性分析模型、加载杆与轮毂为不同材料的线弹性分析模型、考虑各元件间的接触关系及螺栓预紧力影响的非线性分析模型.通过分析与比较,以及典型轮毂的试验验证,研究了以上3种有限元力学模型的优缺点、应用范围及计算的可靠程度,并以典型轮毂为例,用试验验证了模型的准确性.研究表明:加载非线性模型较为准确;线弹性模型可以用于轮辐处易发生疲劳破坏的分析;加载杆与轮毂材料异同对最大等效应力影响不大;对螺栓孔附近易破坏的轮毂,应采用考虑预紧力影响及非线性接触的模型.

In the development stage of aluminumalloy wheel,the bending fatigue test is one of the bench tests that must be passed,to which the trial casting wheel on a small batch basis was put.To avoid experiments of blindness,reduce the number of tests,cut down the experiment cost and improve the reliability,the finite element method is applied,which is one of the advanced technologies in design stage.To apply the technology correctly,the effective calculation model must be built to simulate bench tests.Based on the theoretical analysis and practical case,considering the nonlinear contact relations from pretightening of blot and the material of difference between loading bar and wheel,three finite element models of bending fatigue tests were built,such as integral linear elastic model with loading bar and wheel in the same material,the separated linear elastic model with loading bar and wheel in different material,the nonlinear model considering with the affection of contact relations and pretightening force.According to analysis and confrontation,and verification test oriented with the typical wheel,theirs advantages and shortages,stress range and computing reliability were studied;the veracity of models was verified with the test of a typical wheel.The research shows the nonlinear load model is corrected,the linear elastic model can be used to analyze the fatigue of wheel which is easy to be broken near bolt hole,and the samedifferent material of loading bar and wheel is less influential on the most equivalent stress,and the nonlinear contact model,considering with the affection of contact relations and pretightening force,was applicable to the analysis of the wheel which is easy to be broken near bolt hole.