Study On Thermally Induced Vibration Characteristics Of Composite Laminates

Composite laminates have been widely utilized in the aeronautics and astronauticsindustries due to the advantage the high specific strength, high specific modulus andstrong designable ability. In such application environment, it will suffer external loadslike high speed and high temperature, so it is necessary to analyze the vibrationcharacteristics in certain loads.In this paper, the vibration characteristics of composite laminates is analyzed underthe thermal loads, during which the viscoelastic properties is considered, thetemperature distribution is calculated and the vibration characteristics, the influencingfactors is studied.First, the transient temperature distribution and the change pattern under externalthermal loads are studied and the result shows that the temperature is quasi-linear alongthe thickness, the temperature difference between two sides maintain constant afterreaching equilibrium.Second, vibration performances of different layouts are calculated and it revealsthat the bigger angle of the outside plies will reduce the natural frequency, and theconsideration of the viscoelastic properties of the middle ply will enhance this law.Viscoelastic properties of the middle ply and the thermal loads will influence harmonicresponse curve and vibration modal; viscoelastic properties of the middle ply willreduce the peak amplitude and the number of the peaks.Finally, the thermal induced vibration of the45°/c/45°layout is studied, andchanges in the vibration rule are analyzed when the fiber content, ply angle of twooutside plies, damping factor, transient modulus and the amplitude of the thermal loadsvarious. The vibration is characterized by the vibration amplitude in thickness direction,vibration attenuation time in transverse direction and the vibration period in thetransverse direction. Increase of the fiber content will weaken the structure’s thermalvibration, increasing ply angle of outsides makes the period of vibration in transversedirection larger. But the increase of transient modulus decreases vibration period of thetransverse direction. And the external thermal loads will improve the maximumvibration amplitude.Conclusions from this study provide valuable references for the design andapplication of composite laminates under thermal loads.