Damage identification method for smart composite cantilever beams with piezoelectric materials

Recently, composite laminated structures have been applied to many structures of vehicles. Since interlamina strength of the structures is relatively low, damage, such as delamination, can be easily induced by an accidental impact. Since delamination is interior and invisible from the outside, it is important to inspect it by non-destructive testing (NDT). Conventional NDT methods, such as X-ray and ultrasonic inspection are expensive and time-consuming to inspect a large area of the structures. The present study proposes a damage identification method for composite structures using natural frequency change and response surfaces. The proposed method is suitable far health monitoring system using piezoelectric actuators and sensors since natural frequency can be measured easily by using them. In the present paper, damage identification of a CFRP cantilever,beam and plate is performed. As a result, it is shown that there are good agreements between actual and predicted damage parameters, which are damage location, length and stiffness degradation ratio of the damaged area.