Application of the finite element methods in long-term simulation of the multi physics systems with large transient response differences

Application of the Finite Element Method (FEM) and the Multibody Dynamics Method (MBS) allows analyzing of complex physical systems. Complexity of the system could be related both to the geometry and the physical description of phenomenon. MBS is the excellent tool for analyzing statics or dynamics of the mechanical systems. MBS permits tracking of Multi Body System transient response for the long-term simulations and application of any arbitrary set of mechanical forcing functions. However, this method does not allow observing state of the continuum systems. Besides, applying forcing functions other than mechanical ones (i.e. general forces or displacements) is troublesome in MBS. In case of FEM most of algorithms encounter continuity conditions across the element boundaries , and thanks to this FEMis one of the most suitable calculation method for continua multi-physics systems (i.e. thermo-structural, electro-thermo-structural, magneto-thermo-structural, MEMS, etc.). Common problem with FEM is that there are major calculation difficulties when long-term simulation results are required and/or large relative motions are present in the system. Drawbacks of FEM and MBS could be overcome with use of algorithm based on the modifled Hybrid Finite Element Method presented further in this paper. Traditional Hybrid Finite Element Method model consists of rigid end deformable elements, system matrices derived for all compound elements are calculated concurrently. In this approach both advantages and disadvantages of FEM and MBS are transferred to the model. Proposed modified Hybrid Finite Element Method algorithm exploits two corresponding coupled discrete models, one containing FEM elements and the other MBS only. Both models are coupled by means of forcing functions. Such approach is applicable for the multi-physics systems with large transient response differences.