Numerical and experimental study on the nonlinear dynamic response of a ceramic matrix composites beam

In this paper, nonlinear dynamic responses of a unidirectional ceramic matrix composite (CMC) beam are studied both experimentally and numerically. Frequency-sweep tests are performed to study the dynamic response of a CMC beam under swept harmonic loads. Constitutive tests, which include axial loading and unloading, were performed to study the constitutive response of a unidirectional CMC under a complicated load history. The shear-lag model is extended to three-dimension (3D) and the values of parameters in this model are certificated by experimental result. The finite element method combined with the shear-lag model is used to simulate the dynamic response of CMC beams under swept harmonic loads. The experimental and numerical results revealed that the variable stiffness of the CMC leads to amplitude saltation under swept harmonic load. The natural frequency of the CMC beams changed with the magnitudes of the external load. Based on the dynamic simulation model, the effects of parameters in constitutive model on the dynamic response of CMC beam are also discussed.