Structural Integrity Monitoring by Vibration Measurements

This paper presents a comparative study on several approaches of structural dam-age diagnosis based on vibration meas-urements. Stochastic subspace identifica-tion method is used to identify modal pa-rameters and to generate a Kalman predic-tion model, which are taken as damage-sensitive features for structural damage detection. A statistical process control technique based on principal component analysis (PCA) is also presented. An im-provement and enhancement of PCA is proposed. It is assumed that without dam-ages, structural responses should remain approximately in a hyperplane defined by the principal directions of data. Damage localization is explored with these meth-ods. As only the measured output signals are needed, the methods are convenient for on-line monitoring. The efficiency and limitation of the proposed methods are illustrated by numerical and practical ap-plications.