Abstract:

Based on the spectral finite element method(SFEM),a spectral finite element model is developed for a delaminated laminated composite beam coupled with a surface-bonded piezoelectric actuator/sensor.Ultrasonic guided wave excitation and propagation characteristics of the coupling system are researched by numerical simulation,and the interactions between the guided wave and the defect are analyzed.The composite beam is based on the Timoshenko beam theory and the piezoelectric wafer layer is represented by the Euler Bernoulli beam theory in the model.The beam/piezoelectric wafer coupled governing motion equations and the boundary conditions in time domain are obtained by using the Hamilton's principle,and then the spectral finite element model is formulated by transforming the coupled governing equations into frequency domain via the discrete Fourier transform.The high calculation efficiency and the ability of the present model to accurately predict the wave propagation in the composite beam are verified by comparing with the finite element method results.Then the interactions between the waves and the damage are discussed.The results show that the guided wave can generate reflection wave from the defect,and that the arrival time and the amplitude of the reflection wave are related to the location and the length of the defect.

Key words: laminated composite beam;delamination damage;spectral element method;piezoelectric actuator sensor