Structural stress calculation method of variable cross-section structure

The invention discloses a structural stress calculation method of a variable cross-section structure in the technical field of fatigue life evaluation of welding parts, which comprises the following steps: S1, distributing node numbers of concerned parts in sequence, S2, determining a structural stress extraction direction, S3, outputting finite element calculation results and meeting the requirement of unit quantity, S4, comparing the structural stress calculation results, and S5, calculating the structural stress of the variable cross-section structure. The method is not only suitable for uniform-thickness regular components, but also suitable for variable-thickness space complex components. According to the method, after calculation is completed through finite element software, node force and node coordinates of a concerned part are extracted, scientific engineering calculation software is used for processing the node force and the node coordinates, and data such as the variable cross-section thickness, a