Abstract
A thermal environment has a complex influence on the dynamic characteristics of fiber-reinforced composite materials and structures. It is challenging to consider the effects of high temperature and external vibration energy simultaneously on their nonlinear vibration response. In this research, the material nonlinearities, due to both the excitation amplitudes and the high temperatures, are studied for the first time, and a new nonlinear vibration model of fiber-reinforced composite thin plates in a thermal environment is proposed by introducing the nonlinear thermal and amplitude fitting coefficients simultaneously. Then, based on the classical laminated plate theory, the complex modulus approach, and the power function and the Ritz methods, dynamic governing equations in high-temperature environments are derived to solve the nonlinear natural frequencies and vibration responses and damping parameters. Moreover, the three-dimensional fitting curves of the elastic moduli and loss factors, excitation amplitudes, and temperature values are obtained so that the key nonlinear fitting coefficients in the amplitude- and temperature-dependent model can be identified. To validate this model, the experimental tests on CF130 carbon/epoxy composite thin plates are undertaken. It is found that the 3rd and 5th natural frequencies, vibration responses, and damping results obtained from the nonlinear model are consistent with the experimental measurements, and the mechanism of nonlinear thermal vibration behaviour is revealed.
Highlights
Fiber-reinforced composites are widely used in the aviation, spaceflight, navigation, and weapon industries because of their light weight and excellent mechanical properties [1,2]
This is inconsistent with the finding that some fiber-reinforced composite thin plates (FCTPs) exhibit the amplitude-dependent vibration phenomenon due to the viscoelastic property of matrix materials [39,40,41]
It should be noted that a varied temperature correction coefficient κ needs to be chosen in the fitting process if the magnitude of U∆ /U0 under different excitation amplitudes and temperatures shows a significant difference, which will somewhat affect the calculation accuracy of the nonlinear vibration parameters of FCTPs, yet the calculation errors are within an acceptable range
Summary
Fiber-reinforced composites are widely used in the aviation, spaceflight, navigation, and weapon industries because of their light weight and excellent mechanical properties [1,2]. Under the assumption of first-order shear deformation theory, Duc et al [22] predicted the nonlinear vibration response of functionally graded material plates subjected to mechanical and piezoelectric loads in a thermal environments. By taking into account the temperature-dependent material properties, Taleb et al [36] developed a novel hyperbolic shear deformation theory for the vibration response prediction of the supported functionally graded plates in a thermal environment. To more accurately predict the dynamic characteristics of those composite structures in a thermal environment, it is necessary to consider the nonlinear influence generated by external vibration energy This is inconsistent with the finding that some fiber-reinforced composite thin plates (FCTPs) exhibit the amplitude-dependent vibration phenomenon due to the viscoelastic property of matrix materials [39,40,41]. It has discovered that the nonlinear dynamic parameters of FCTPs are affected by the continuous change of external excitation energy and thermal environment
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