Penalty formulation for postfilling analysis during injection molding

We propose an approximate method that can simulate the packing stage during the injection molding using the penalty parameter method. In order to account for the compressibility effect, an update scheme based on similarity between the slightly compressible and the penalty formulations is proposed. The method allows for solving the entire injection molding process using a single algorithm with the penalty method in spite of the transition from the incompressible regime during the filling stage into the compressible regime for the packing stage. Several test cases have been presented to prove the validity of the method. It has been shown that the accuracy of the roposed method is identical to that of the mixed method.