COMBINED LINEAR - GEOMETRICALLY NONLINEAR FEM MODELING FOR HIGHLY EFFICIENT DYNAMICAL SIMULATIONS

Software packages for multi-body system (MBS) dynamics are efficient tools for modeling interconnected rigid and/or flexible bodies. Consideration of flexible bodies in commercially available MBS software packages is limited to linear elastic behavior. In many cases though, structural behavior includes geometrical nonlinearities, which are, however, restricted to a relatively small structural sub-domain. The paper addresses the idea of combined linear - geometrically nonlinear FEM modeling that aims at high accuracy with optimal numerical effort. The approach can be of great importance in all areas where highly efficient MBS or FEM models are required, such as robotics, car industry, etc. The idea is demonstrated in the paper on an example involving a tower crane with a suspended load. The model reduction based on modal superposition technique is used for the linear part of the model, which further improves the numerical efficiency. Dynamics is resolved by means of an explicit time integration scheme. The results by the proposed approach are compared with those computed by rigorous geometrically nonlinear approach in commercially available software package ABAQUS. Key words: geometrical nonlinearity, modal superposition, tower crane, explicit time-integration schem