Technical note: Coherence analysis of the transfer function for dynamic force identification

Identifying dynamic forces with structural response signals is important when direct measurement is difficult or impossible. The minimized condition number method was introduced to reconstruct the forces with selected spatial distribution of response locations. This paper presents another way to optimize the selection of the response locations. The coherence of transfer function matrix is analyzed and the coherence factor of the transfer function matrix is introduced to optimize the response locations. Numerical simulations of the coherence analysis show that it is effective and requires less computational effort than the condition number method. The validity of the analysis is verified by applying it to the identification of the suspension forces on a vehicle cab.