A meshfree simulation approach for the refill friction stir spot welding process
By Kirk Fraser (NRC), Francois Nadeau (NRC)

Recently, interest in the refill friction stir spot welding, RFSSW, process has steadily gained. The process is composed of four main phases: 1) work piece clamping; 2) dwell; 3) shoulder plunge/pin retract; and 4) pin plunge/shoulder retract. In the end of the process, a flush surface remains without the remnants of the pin hole that is common in the FSSW process.

Here, we present a meshfree numerical simulation approach that is able to accurately simulate the entire RFSSW process. A fully coupled thermo-mechanics approach is used that allows prediction of temperature evolution, material flow, process forces, and microstructure evolution. The code is validated against various RFSSW parameter sets. Ultimately, the code is a valuable tool to better understand the underlying mechanisms of the RFSSW process and to perform virtual prototyping.