Hybrid Substructure Assembly Techniques for Efficient and Robust Optimization of Additional Structures in Late Phase NVH Design: A Comparison

In certain circumstances, not all desired NVH properties of a given mechanical structure, e.g. a vehicle, are satisfied at the end of a development process. In this situation, NVH properties of an existing structure must be improved while extensive changes of this structure are not practicable. Consequently, additional components such as mass dampers are included to improve the NVH properties. The arising task is to determine the optimal configuration of these additional components. If one assumes that no valid or accurate simulation model of the underlying structure exists, a hybrid substructuring approach is essential. The existing structure is measured at the required positions, the additional structures are modeled virtually, subsequently they are combined to a hybrid assembly. The optimization includes the repeated evaluation of such an hybrid assembly. In this contribution two major strategies are regarded: frequency based substructuring (FBS) and state-space substructuring (SSS). The possibly large number of evaluations imposes a greater demand on the computational efficiency compared to onetime assemblies. Furthermore, properties concerning the robustness towards measurement noise of the assembly technique play an important role. Based on a common notation for both assembly techniques, the relevant properties—efficiency and robustness—are compared on a numerical example.