friction stir welding؛ material flow؛ heat generation؛ thermal simulation؛ poly methyl methacrylate (pmma)

in this study, the effects of linear and rotational speed of the friction stir welding tool was investigated on the heat generation and distribution at surface and inside of workpiece, material flow and geometry of the welding area of poly methyl methacrylate (pmma) workpiece. the commercial cfd fluent 6.4 software was used to simulation of the process with computational fluid dynamic technique. to increase the accuracy of simulation, weld area was modeled as a non-newtonian fluid with pseudo melt behavior around tool pin. the results of the simulation showed at the higher the proportion of rotational speed to linear speed, the material flow in front of the tool and the welding region became bigger. the maximum temperature and turbulence generated heat and material flow were observed at the advancing side. the simulation results were showed acceptable agreement with experimental results. based on the studied parameters, the maximum generated heat was of 115° c, the maximum material velocity was 0.24 m/s around tool shoulder and maximum pressure on the workpiece was predicted 9 mpa.