Efficient Computation on Prediction of Welding Residual Stress of a Large and Complex Offshore Structure

摘要

A mock-up of an offshore structure was prepared by multi-pass welding of several components with different thicknesses, different materials, different grooves, and ultra-long welding lengths. It may be very time consuming to obtain the stress distribution of the mock-up with conventional thermal elastic-plastic (TEP) computational methods. An efficient computation method, i.e. the model separation and stress assembly method, was proposed in the present study to obtain the stress distribution of the mock-up within an acceptable time. The full finite element (FE) model with solid elements was first created and separated into two independent parts, and the stress distribution in each part was obtained by using the TEP FE method. Finally, the full stress distribution in themock-up was obtained by assembling the stress distributions from each part. The computed results show that the predicted stresses of the mockup agree with the measured data obtained by using the hole-drilling method and x-ray diffraction method. Therefore, the proposed efficient method for stress simulation in large and complex structures can guarantee the simulation accuracy within an acceptable computation time on a common computer workstation.