The study on longitudinal wave and transverse wave propagation behavior in FRP composite material

The use of ultrasonic wave technology was anticipated as an important technology in health monitoring of composite materials and/or structures. However, the propagation of ultrasonic wave becomes very complicated in polymer-based composite materials due to reflection, transmission, dispersion and other behavior, which may occur at the interface of the matrix and within the reinforcements. Therefore, in this paper, the elastic wave motion equation is evaluated by using newly developed time domain finite element analysis; the ultrasonic wave motion and its characteristics in a single composite material with/without debonding failure was numerically elucidated. Particularly, the ultrasonic wave mode conversion in the media body and the influences of the fiber/matrix interface and the debonding failure on wave propagation process were clarified. The visualization of both longitudinal and transverse wave during the wave propagation is conducted, and its effectiveness for identifying the complicated wave characteristics is confirmed.