Abstract: A damage identification method combining power spectrum sensitivity and substructure polycondensation technology was proposed. The finite difference method was used in the process of analyzing the sensitivity of the response power spectrum to the structural element area, which solved the problem that the partial differential of the solution parameters is difficult; in addition, the overall structure is divided into several substructures, the Guyan polycondensation technology for undamaged substructures was adopted. Damaged identification of condensed structures is carried out by power spectral sensitivity analysis and the method only needs to measure the response of a few degrees of freedom of the structure to achieve the purpose of damage detection. Finally, the effectiveness of the proposed method is verified by a three-layer and two-span rigid frame model.

Key words: power spectrum sensitivity, method of difference, substructure, Guyan polycondensation, damage identification