2020 Volume 58 Issue 8 Pages 19-25
A three-dimensional (3-D) thermo-mechanical Finite Element Model (FEM) was developed based on ANSYS
Parametric Design Language (APDL) to study the temperature field and residual stresses in the Aluminum Alloy
6061 plate in the formation of bead-on-plate welded by an Adjustable Ring Mode (ARM) Laser. During the weld
process, the laser power of the ring and core of the optical fiber could be tuned separately on-the-fly. The influences
of laser power synergy between the outer ring and the core in the ARM laser beam on the weld geometrical sizes,
weld quality and internal soundness and, subsequently, thermally-induced residual stress distributions were studied
by numerical modeling and experimental investigations. The weld penetration and weld width could be adjusted by
optimizing the power distributions of the outer ring and core spot, through which the residual stress of welds could
be also controllable, and a porosity-free weld could be achievable. The effect of process parameters on the residual
stress concentration in the weld obtained by ARM laser was identified by the developed nonlinear thermo-mechanical
FEM. It can be found that the residual stress distribution in the weld by ARM laser welding varies with the laser
power ratio of center and ring parts. The maximum equivalent residual stress concentrations were always located
at the center of the weld zone and well-distributed uniformly along the weld bead. The XRD residual stress measurement
was also performed to validate the accuracy of the achieved numerical prediction.
