Numerical Methods for Welding Simulation: The Next Technical Step

Numerical methods have been established to simulate welding processes, often based around the use of methods which represent the welding process in a simplified manner. Simplified methods include simultaneous deposition of weld beads and bead lumping where stringers or individual weld beads are grouped together and deposited. These approaches are widely accepted, however the requirement for simplified methods often results in compromises to the solution accuracy usually driven by limitations in data and the capability of computing hardware. In many cases this compromise in accuracy is acceptable providing it is well understood, however there are frequently cases where such simplifications are unacceptable and improved representation of the welding process is required. In practice this generally implies the requirement for a full moving heat source simulation. The transition from simplified simulation methods to the next technical step, full moving heat source simulations, is now possible for a wide variety of scenarios as will be demonstrated in this paper. This paper presents two specific cases, a 3 pass slot weld and a multipass repair weld, where full moving heat source simulations have been considered necessary. For each of these cases the reasons why moving heat source methods are necessary and the benefits that this more demanding simulation technique offers are described. Furthermore the predicted residual stress results are compared with residual stress measurements using a variety of measurement techniques. The work provides an extremely useful insight into how moving heat source methods are now considered a practical analysis method for a wide variety of real world problems. Of further consideration is the fact that in the 2 years since the work reported in this paper was undertaken computing performance would have at least doubled.Copyright © 2008 by ASME