Welding Process Simulation With Simultaneous Computation Of Material Properties.

Abstract

Residual stresses and plastic strains are produced by localized heating and cooling
during welding. These stresses can lead to distortion and under certain circumstances even the
premature failure of welded parts. Thus, residual stresses play an important role as far as the
quality and reliability of a welded construction are concerned.
Formation of distortions and residual stresses in weldments depend on many interrelated factors
such as thermal and mechanical fields, phase transformations, material properties, structural
boundary conditions, types of welding operation and welding conditions1, 2
In the present work, the previous finite element model developed by the authors3 to study the
thermomechanical behavior of the solidifying metal in welding processes is validated using the
analytical solution of Weiner and Boley.4
Also a kinetics based model was integrated into the same multiphysics finite element program
to provide the time evolution of the microstructure.5 The material properties required for the
non-linear thermomechanical analysis are temperature and phase dependent, and this dependency
is accounted for by computing the microstructure evolution and using this information
to estimate the material properties. This is done by assigning temperature dependent material
properties to each phase and applying mixture rules to predict macro material properties.
Finally numerical results are presented to illustrate the evolution of the stress field in a
buttwelded joint.