Efficient mode based approach for the dynamics of jointed FE structures

Technical structures typically consist of several substructures, connected by joints like bolted connections or spot welds. The nonlinear effects occurring locally within the involved joints significantly influence the global dynamic behavior of these structures. Considering these effects during a transient simulation is a challenging task. In this contribution an extension to common mode bases is suggested in order to account for the local nonlinear joint behavior. First the idea of these additional trial vectors is briefly outlined. Two numerical examples, the deflection of a jointed beam structure and the fatigue life assessment of a door slam, emphasize the capability of the proposed approach. The results obtained with nonlinear joint contact consideration significantly differ from the results without contact consideration. By using this extended mode base it is possible to take into account the nonlinear joint contact and its influence on the overall system behavior in a very efficient and accurate way. Excellent displacement results are obtained by the combination of a classical mode base and a manageable number of additional contact modes.