A Multi-Point Force Appropriation Method Based Upon a Singular Value Decomposition Approach

Abstract

Force appropriation methods aim to provide an estimate for the force pattern required to excite a “pure” normal mode in a vibration test where multiple exciters are available. In this paper, a new method based upon a Singular Value Decomposition approach is presented. The appropriated force vector which minimizes the in-phase response components while maximizing the required quadrature components is found, subject to a fixed force norm. The method can accommodate more transducers than exciters and also more exciters than effective degrees of freedom. The method is demonstrated upon a six degree of freedom theoretical model and it is shown that an estimate for the effective degrees of freedom can be obtained.