STUDY ON THE THICKNESS EFFECT TO FATIGUE STRENGTH OF JOINT

Abstract

The phenomenon which the fatigue strength decreases even with the same weld joint type, due to an increase of the plate thickness or a combination of the plate thickness is known as a plate thickness effect. It is considered that stress concentration and stress gradient at the fatigue crack initiation position are factors of the plate thickness effect, and some experimental and analytical studies have been conducted. However, in the case of welded joints, it is not easy to clearly distinguish these influencing factors, and it is hard to say that the plate thickness effect is fully understood. The object of this study is to consider the thickness effect on the fatigue strength through FE analysis and comparison with the experimental results. As a result, the plate thickness effect observed in the experiment was able to be reproduced, and it was found that the crack initiation life was a major factor of the plate thickness effect observed in the experimental research.