용접시편 응력-수명 선도를 이용한 샤시부품의 내구수명 평가

Automotive chassis parts are commonly fabricated by arc welding. Severe stress concentration and low fatigue strength tend to cause fatigue crack near the weld. Thus, fatigue life estimation of the weld is very important for the durability of the chassis parts. This study presents a method for estimating the fatigue life of the weld. The fatigue life for 10 kinds of weld specimens is measured by fatigue test and structural stress at the weld is calculated by finite element analysis. The stress life curve of the weld is obtained by statistical analysis of the fatigue life and structural stress. Using the stress-life curve for the weld, fatigue life estimation of a front lower control arm is carried out by finite element analysis. The fatigue life estimated by simulation is compared with test results. It is found that the proposed stress-life curve of the weld provide a good estimation of fatigue life.