International Journal for Numerical Methods in Engineering vol:87 issue:11 pages:1025-1045
Body flexibility is of ever-increasing importance in multibody simulation. The current state-of-the-art simulation techniques typically have difficulties with systems in which flexible bodies can be loaded in many degrees of freedom (DOFs). However, in many applications, loading is possible in many DOFs but only few are loaded simultaneously at any given moment, such that at any moment only a low-dimensional part of the reduced body flexibility description contributes to the solution. Modal Base Switching, the methodology proposed in this paper, exploits this by judiciously choosing the body flexibility mode set and at any moment only including those modes that contribute to the solution. Modal Base Switching does not improve simulation accuracy, however it can significantly reduce simulation times.
In a numerical experiment, results using Modal Base Switching match results for a conventional model using the same mode set. The approximation errors are negligible compared the accuracy loss encountered when using a mode set without compensation for the quasi-static response of the high-frequency dynamics, while both simulation results are obtained at a comparable computational cost. Modal Base Switching numerically introduces discontinuities when removing a mode from the mode set. This is overcome by time integration schemes exhibiting high-frequency numerical damping.