DAMAGE LOCATING FOR COMPOSITE BEAM STRUCTURE BY CROSS CORRELATION ANALYSIS WITHOUT REFERENCE NODE

An improved method to locate the damage of a composite beam structure is proposed, based on the cross correlation function method. In this method, no reference node is needed. Two sets of responses with the same length of each node of the intact structure are measured, one set is used as the reference signal and the other set is used as the characteristic response signal. Then a set of characteristic response signals of the damaged structure is measured. According to the cross correlation function method, the maxima values of the cross correlation function between the reference signal and the two sets of characteristic response signals of intact and damaged structures are calculated respectively, the relative change of the maxima values are used as a damage index. The difference of the damage index of each node is served as the damage location index. The feasibility and the effectiveness of the proposed method are verified by damage detection tests of a honeycomb beam with single damage and multiple damages respectively. The test results show that there is no need to build the finite element model of the structure, and only the response signals of the structure under a random excitation are needed to locate the damage.