Reference-free mixed FE-MBS approach for beam structures with constraints

In this paper, an efficient way to simulate elastic beam structures with large translations and deformations is derived. The formulation is close to classical multi-body system (MBS) formulations and makes use of two coordinate sets: One providing equations of motion in a compact form and one for the coupling of single elements to one finite-element structure. Therefore, a coordinate transformation is needed. Constraints within the structure are considered following the common formulations of MBSs. Both uni- and bilateral constraints can be modelled. The system is extended to impacts on the structure. The model is validated by a comparison to a classical FEM model. A beam under different loads is given as an example especially for the treatment of constraints and impacts.