FEM Calculation of Frequencies Variation Caused by Residual Stress Distribution in Welded Structures

O. Charette, H. Champliaud, and M. Thomas (Canada)

Keywords

Residual stress, modal analysis, finite element, welding.

Abstract

All manufacturing and forming processes induce residual stress in mechanical parts and experiments have shown that residual stress distribution affects the natural frequencies in structures. In practice, measuring residual stress is still difficult, and cannot always be done without destroying the part. Even if some non-destructive methods exist for measuring the residual stress, they cannot be applicable on all parts and results are sometimes more qualitative than quantitative. Numerical methods such as the finite element method (FEM) provide tools for predicting the state of stress resulting from welding, and using modal analysis has appeared as an interesting alternative for measuring and predicting the residual stress. Simulations of welding on a plate have been done using the commercial software ANSYS. Results show that after the welding simulation, the natural frequencies have risen by about 5 to 7 percent in comparison with a free of stress plate.

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