Hi Kp_9079,nYou turn mass scaling on in the analysis settings:nnI don't know all the details about the settings but as I understand them Minimum CFL Time Step sets the smallest time step you allow for the solver and if the time step would go below it mass scaling will be applied to keep the time step larger than that. Maximum Element Scaling gives the maximum amount how much the mass of an element can be scaled and Maximum Part Scaling how much the mass of a part can be scaled up. I'm guessing that Update Frequency defines how often the solver checks the need of mass scaling and if needed updates the mass scaling values for the elements.nAlso, in case if you didn't know, time step is defined by the characteristic length of the smallest element in your mesh based on the CFL condition. So by increasing the mesh size and trying to make sure that your elements in the model are as equal size as possible with each other can help to reduce the simulation time. Also using hex mesh with linear element order is highly recommended. nHopefully this helps and others can comment also since I have just got started with learning about explicit dynamics too. n