Muhammad Abid - First Author. Dr. Muhammad Abid, Assistant Professor
Muhammad Siddique - Second Author. Muhammad Siddique, PhD Student, GIK Institute of Engineering Sciences and Technology,Topi, NWFP, Pakistan

his paper presents a detailed 3D finite element (FE) study to investigate the effect of mechanical constraints on welding distortions and residual stresses in pipe flange joint. A sequentially coupled non-linear transient thermo-mechanical analysis is performed to simulate complex welding phenomena. Comparison of effects is made between free welded condition during pipe-flange welding (without constraining except tacks) and after assembling (constraining) the flange joint and then welding. Contact pairs are used between the matching surfaces of different structural components. FE models are validated with experimental data for deformations. From results axial displacement and tilt of flange face are found strongly dependant on the constraints. However, residual stresses have a weak dependence on the constraints set.

Finite Element Simulation, Effect of constraints, Pipe-Flange Joint