Abstract
This paper presents an approach to minimize weight of suspension parts while keeping the fatigue strength base on a non-parametric boundary shape optimization theory. As an index for the fatigue failure, we considered the maximum valueof absolute principle stress in a suspension part evaluated from actual loading history. For reshaping, we employed the traction method to keep the smoothness of original boundary.To reduce computational time, we considered a conventional method to select critical loading cases from actual loading history. By our approach, we obtained about 10% weight reduction while keeping the maximum value of absolute principle stress constant.