Appendix I: Using a BDF from which an MNF was Generated

Users of the linear flexible body may wonder if the same bulk data file (BDF) used to generate a body's modal neutral file (MNF) can be used as the basis for a nonlinear flexible body. This is possible but limited to scenarios where one is interested only in geometric nonlinearity. To properly represent material nonlinearity a sufficient amount of work must be done to the BDF (for example, defining nonlinear material models) that use of an FE pre-processor is required. If only geometric nonlinearity is desired then direct use of an MSC Nastran SOL103 BDF (SOL103 is the MSC Nastran solution sequence for MNF generation) is supported here.