Development of a Hybrid FE-SEA-Experimental Model: Experimental Subsystem Characterisation

This paper is concerned with Shorter and Langley's hybrid method [JSV, 288(3):669-699, 2005] and the incorporation of experimental subsystems. In particular, this paper will address the form of the experimental data required and the procedures necessary to obtain it. Further discussion regarding the theoretical construction of the hybrid model will be presented in a companion paper. The hybrid method facilitates the coupling of deterministic, i.e. Finite Element (FE), and statistical, i.e Statistical Energy Analysis (SEA), subsystems, thereby offering a practical solution to the mid-frequency problem, where neither FE nor SEA are appropriate. Whilst the hybrid method, amongst other numerical methods, is able to predict the passive properties of complex vibro-acoustic structures it is not yet used to model the mechanisms that lead to vibratory excitation. The present paper aims to extend the hybrid method's capabilities through the incorporation of experimental data, for example, in prescribing the operational behaviour of an active subsystem. The paper will introduce the in-situ blocked force approach to structural source characterisation, an in-situ characterisation method for resilient coupling elements such as vibration isolators, and recap the state-of-art in dynamic sub-structuring. The above will facilitate the construction of a virtual assembly and provide the experimental quantities required in the construction of the hybrid model further discussed in the companion paper.