A VALIDATED MODEL OF THE CYCLIC STRESS STATE OF AN A356 AUTOMOTIVE WHEEL AND ITS IMPACT ON FATIGUE LIFE

摘要

Fatigue life is a key consideration in the design of cast aluminum alloy automotive wheels which offer both improved strength-to-weight ratio and fuel efficiency. The cyclic in-service (applied load and residual) stress distribution within a wheel is a limiting factor determining a wheel's fatigue performance. In this investigation, a through process modeling methodology was applied to predict the cyclic stress state of an A356 automotive wheel subject to a bending moment. The predicted residual stresses arising during heat treatment and released through machining were validated by a destructive strain measurement technique. With the residual stress state used as an initial condition, the variation of the in-service stress state during a bending test was predicted. The measured strain variations within the wheel for a series of different bending loads were found to agree well with the predictions. These results were incorporated into a through process modeling approach to assess the fatigue performance of the wheel.