Analysis of nonlinear damping characteristics of fiber-reinforced composite thin plates with temperature dependence

In this paper, a complex exponential method is proposed to analyze the nonlinear damping issue of temperature-dependent fiber-reinforced composite thin plates. First of all, by considering the nonlinear effects of thermal environment on the elastic modulus of fiber-reinforced composite materials, this method is employed to establish the damping model of the compsite thin plates, and the nonlinear damping and natural frequency in this model are solved theoretically. Then, the relative error function of the natural frequencies is constructed according to the experimental results under different temperatures, and the determining method of fitting coefficient in the model is explained in detail based on the iterative and fitting techniques. Finally, a case study on test and verification is carried out by taking the TC500 carbon fiber /YD127 epoxy resin composite thin plate as a research object. The results show that the maximum calculation error of the first six modal damping ratios and natural frequencies of composite thin plate obtained by the complex index method at three temperatures, including 20, 50 and 150℃, does not exceed 9.33%, which verifies the correctness of this analysis method. In addition, it is found that the damping of such a composite structure goes up with the increase of temperature. However, the sensitivity of the high order damping to the temperature is reduced with the increase of the modal order. © 2020, Nanjing Univ. of Aeronautics an Astronautics. All right reserved.