Sum Interface Forces Using MPCs

This tool creates MPC equations that can be used to sum interface forces, such as for use in some types of bolted joint analysis. This process can even be used for dynamics since it maintains phase information. The DMAP alter creates DMIG cards which define six columns of a matrix corresponding to the resultant forces and moments about a node. The DMIG cards can be reformatted as MPC cards to recover resultant loads from the model. Tip: Calculations should always be checked by applying unit loads to the model and reporting the displacements of the resultant nodes. These should be the resultant forces and moments through each cut.

The alter was updated on November 29, 2017 to correctly transform results to the displacement coordinate system of the selected node. It was further updated on March 17, 2021 to add additional user options.

See this tutorial for a demonstration of generating inputs for the alter, converting the DMIG results into MPC cards, and using unit loads to check the MPC equations.