Improving the Robustness of Numerical Simulation Approach by Including Process Results

Mechanical joining is a permanent fastening process used in the automotive industry. In transmission components like flywheel & clutch assemblies, it plays an integral role in fastening the sheet metals. Residual stresses of any kind can lead to dimensional and structural instability. Now a general practice among numerical analysts is to carry out the simulation using standard CAD model. They often neglect the changes in the dimensions, residual stresses developed in the part and material hardening effect due to various processes involved in manufacturing. Such an approach does not take into account the real world scenario. This could result in over or under estimation of the product by numerical simulation. Hence, it has become a necessity for the analysts to find ways to have a robust approach. The solution presented here is to compute forming of rivet at nominal dimensions/hardness, map the residual stresses and plastic strains of the formed rivet in the standard computational software and simulate it for the assembly loading conditions. This approach augments our FEA simulations to simulate actual conditions and produce a robust design. This study can be further extended to other products involving mechanical joining processes.