Dynamic Modeling And Analysis Of Hard -Coating Beam And Hard-Coating Plate

Hard coating is material made of metal and ceramic, mainly used for thermal barrier, friction resistance and corrosion resistance of the composite structure. It has been found in the recent researches that the hard coating has vibration attenuation effect, and is particularly suitable for thin-shell structures in aviation, (such as blade, cylindrical shells, etc.) In order to effectively implement the hard coating for damping, it’s needed to create a dynamic model of hard-coating composite structure to analyze the damping mechanism. However, as a new kind of damping technology, the research is still inadequate, which has severely limited the application of hard coating. Based on the mechanical characteristics of the hard-coating materials, it is studied here how to model the hard-coating composite structure. The main research contents of this paper are as following:First of all, the vibration performance of hard-coating cantilever beam under base excitation is analyzed based on composite beam theory. By means of the complex modulus, parameters of coating are included in the structural dynamics equations and the analytical model is successfully set up and validated by finite element method. Then, based on the analytical model, the effect of coating’s Young’s modulus, loss factor and thickness on the dynamic characteristics of composite beams is studied.Secondly, based on composite plate theory, the vibration of hard-coating cantilever plate under base excitation is analyzed. Complex modulus is used to introduce coating’s parameters. By use of two-dimension beam mode functions, the Lagrange equation of this composite plate is derived, and the analytical expressions to solve the natural frequencies and vibration response are obtained and validated by finite element method. Based on the analytical model, the effect of coating’s parameters on the dynamic characteristics of composite plate is studied.Thirdly, as the mechanical properties of hard coating change with different excitation amplitudes which is called amplitude dependence or strain dependence, the composite structure also exhibits nonlinear mechanical characteristics. Considering the strain dependence of hard-coating materials, an iterative finite element method is adopted to analyze the dynamic characteristics of composite structure and a reasonable calculation flow is also proposed. Then, a hard-coating beam and a hard-coating plate are analyzed and validated by experiment respectively.Finally, the analytical analysis is taken of the composite beam, considering the strain dependence of hard-coating materials, the nonlinear dynamic equation is created. Furtherly, an iteration method and Newton-Raphson method are utilized to obtain the natural frequencies and vibration response of composite beam. The accordance between the results calculated by analytical analysis and FEM validates the accuracy of analysis model.This paper can provide reference for the selection and preparation of hard-coating material or further study on the damping mechanism of coating material. And it can also provide the support for the application of hard-coating damping technology in aviation.