Design sensitivity analysis of a system under intact conditions using measured response data

Design sensitivity requires knowledge of the accurate characteristics of system dynamics to determine the solution parameters—eigenvalues or eigenvectors. This paper presents a new form of sensitivity analysis based on transmissibility functions that can indicate the appropriate candidate node for minimal design modification. The proposed sensitivity analysis uses only measured response data and is performed under intact conditions without any system identification. The feasibility of the proposed sensitivity analysis is first verified through both an experiment and a computer-aided analysis of the uniaxial vibration of a notched beam; then its methodology is investigated by simulation involving a 5-degrees-of-freedom system.

► New form of sensitivity analysis is suggested based on response data only.
► Sensitivity index is function of both the nodal response and the transmissibility.
► Proposed method predicts a consistent nodal sensitivity under different forces.
► Dynamic indicator consists of the variation of eigenvalue and the response ratio.
► Simulation shows that sensitivity index well matched with dynamic indicators.