| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for predicting fatigue life of a welded structure such as an automobile component and a railroad vehicle which is formed by welding a plurality of thin plates. <P>SOLUTION: When predicting fatigue life by modeling a welded structure by a shell element in a finite element method, a welded joint in the welded structure is modeled so that a weld toe becomes a shared node position for a metal plate and a welding part, the stress of a surface position of the metal plate on the shared node position, preferably a rectangular direction to the weld toe, is calculated, evaluation stress is calculated from the obtained stress, and fatigue life is predicted based on the evaluation stress and a previously prepared fatigue life diagram. The evaluation stress is calculated by the following expression σ<SB POS="POST">eqt</SB>=(σ<SB POS="POST">top</SB>+σ<SB POS="POST">btm</SB>)/2+(σ<SB POS="POST">top</SB>-σ<SB POS="POST">btm</SB>)/4. Provided that σ<SB POS="POST">eqt</SB>is the evaluation stress, σ<SB POS="POST">top</SB>is the stress of the weld toe side metal plate surface on the shared node position, and σ<SB POS="POST">btm</SB>is the stress of the metal plate surface on the opposite side of σ<SB POS="POST">top</SB>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
