Employing a variable modal basis for small deformation flexible multibody formulations.

One of the main challenges for small deformation flexible multibody simulations is the a priori selection of the required modal basis. Often, to guarantee the accuracy of the component mode synthesis, an excessive amount of mode shapes are accounted for in the model basis. Hence, to address this problem, the variable modal basis for small deformation flexible multibody formulations is introduced. It allows truncation of the initial modal basis to minimize the required amount of active mode shapes while maintaining accurate results. Furthermore, the proposed framework is independent of the chosen small deformation flexible multibody formulation. The modal variation is achieved by neglecting mode shapes based on their individual energy content. Hence, the corresponding set of dynamic and constraint equations, as well as the generalized coordinates and Lagrangian parameters, reduce accordingly. Once mode shapes are neglected, their energy content is no longer evaluated. Therefore, reintroducing these mode shapes is based on the change in total flexible energy of a flexible body. To validate the accuracy of this approach, a comparison is made between the results obtained from implementing a variable modal basis and those obtained from a regular constant modal basis. [ABSTRACT FROM AUTHOR]