Analysis of weld residual stresses by FINAS (1)

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Prediction of weld residual stresses by a general finite element code is beneficial to the improvement of the accuracy of integrity assessment and residual life assessment of FBR plants. This reports develops an evaluation method of weld residual stresses using FINAS. Firstly, we suggested a basic procedure derived from parametric analyses with a simple weld joint model. The procedure can be summarized as follows: (1)For heat conduction analysis, prepare different models corresponding to the number of layers to be modeled. Hand over the analytical results to the following model. (2)Use multi-linear stress-strain curves for modeling the stress-strain response of base metal and weld metal. Use the isotropic hardening rule. (3)When metals are melt, use a user-subroutine to keep stresses from arising. (4)Put the thermal expansion coefficient as zero when heat is being input. Then, using the above procedure and TIG welding, we predicted the weld residual stresses of plate and tube. The results agreed well with the other reports, showing the suggested procedure was reasonable.