FINITE ELEMENT ANALYSIS OF RESIDUAL STRESSES IN WELDED STRUCTURES

One of the problems during welding process is residual stress or welding distortion. This
situation affects the integrity of welded structures because the zone that has high
residual stresses will have a greater tendency to crack or fail. The objective of this
project is to simulate the residual stresses in the welded structure by using finite element
analysis. The ANSYS software will be used to simulate the welding process. In this
simulation, Gas Tungsten Arc Welding (GTA W) had been chosen as welding type and
the welded plate will undergo butt joint process to join them together. Birth and death
elements were used to simulate the movement of the welding process.
The temperature-dependent material properties have being applied to the model. Bias
method has been applied at the area of concern especially at the area where the heat flux
is being applied. The heat convection need to be applied to the model and for the
welding process, heat flux will be applied in the weld zone element from the first
element until the last element at the welding zone. The prediction of welding residual
stresses using finite element method starts with thermal analysis and followed by
structural analysis.
A few tests will be done by varying the plate thickness. The results from the variation of
plate thickness will be compared. Data that will be interpreted from the model are stress
versus distance along the welding line, fusion line and along the mid section. From these
result, the residual stresses will be investigated.