| Ceramic Matrix Composites (CMC) exhibits excellent capabilities such as high temperatureresistance. This material is considered as the perfect material for high temperature structures whichare used in the aero and space aircrafts. CMC often support complex dynamic load. The research ofthe vibration characteristics is one of the critical issues needed to resolve in project. Therefore, it willbe important to develop vibration response analysis method of CMC.A new method, which is used to simulate the vibration of CMC beam with the matrix cracks, isdeveloped in this paper. In micro-scale, the unidirectional CMC stress distribution equations arederivate in every loading-unloading processes. Based on these equations, stress-strain response isderivate. In macro-scale, FEM equations, which simulate the vibration response of CMC beam, isderivate. Then each time step is iterative solved with central difference method. Finally, thesimulation of the CMC cantilever beam vibration is completed.The simulation of vibration responseof a Nicalon/CAS-II beam subject to harmonic loading and pulse loading is performed as an example.First, the effect of time step and numbers of Gaussian integral point to computational accuracy andefficiency is discussed. Then, two vibration responses under harmonic loading and pulse loading hasbeen achieved. The results are compared with the response of elastic beam. The first order naturalfrequency and modal damping coefficient have been achieved from the calculation results. Thevibration response result near the resonance point show that nonlinear characteristic exists obviously.Hammering method eddy current method have been adopted in the vibration experiment toobtain the first two order natural frequency and modal damping coefficient. Nonlinear characteristicthat the first order natural frequency changes with amplitude of harmonic loading has been found inthe experiment. Finally, we compare the experiment results with the calculation results. |
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