抄録
The ultrasonic propagation behavior of CFRP laminates immersed in water at oblique incidence is studied theoretically by using the stiffness-matrix method. Spring-type interlayer interfaces are employed to take account of the influence of interlayer resin-rich regions, and the dependence of the amplitude transmission coefficient on the interlayer interfacial stiffness, frequency, and the angle of incidence is investigated. The dispersion relation for an infinite layered structure is calculated by the Bloch's theorem, and it is shown that the band-gap is closely connected with the frequency range where the transmission coefficient of the finite layered structure becomes almost zero. Comparing with the experimental transmission coefficients for an 11-layered CFRP laminate, the theoretical results are verified.
