Ziaee - Ph.D student, Mechanical department of shiraz university, Shiraz ,Iran
Kadivar - Professor, Mechanical department of Shiraz University, Shiraz, Iran

Accurately predicting welding residual stresses and developing a convenient welding sequence for a weld system are pertinent tasks since welding residual stress is inevitably produced in a welded structure. In this work the effect of layer, block and cascade welding sequences on thermo-mechanical response of thick shell weldments is studied by the use of a 3-D thermoviscoplastic model. Anand's viscoplastic model is used to simulate the rate dependent plastic deformation of welded materials. Modeling of the welded region in the present study has been done on the basis of "isothermal melting pool" approach. The temperature dependency of thermal and mechanical properties of material is considered in analysis and the effect of welding speed is introduced into the model, as well. Furthermore, this investigation provides an convenient welding sequence to enhance the fabrication process of circular welded.

Different kind of welding sequences،3D finite element model، Viscoplastic model، Anand model