非比例負荷強さを考慮した疲労寿命予測法の溶接構造評価への適用

抄録

In fatigue design for transport machinery with complex stress, it is important to consider non-proportional loading. In this paper, a method for prediction of fatigue life considering life degradation by non-proportional loading was applied to fatigue life prediction for welded joints. Fatigue tests were conducted on welded joint specimens under non-proportional loading with planar tri-axial fatigue testing machine. We found that the method recommended by the IIW made it possible to evaluate on the safety side. However, it was shown that the greater non-proportional loading intensity, the greater predicted fatigue live ratio (predicted / measured). On the other hand, we found that the predicted fatigue lives calculated with multi-axial stress were within a factor of 2 against the experimental results.