Damping contributions of coatings to the viscoelastic behaviour of mechanical components

Coating layer technology is known in literature as an effective tool for modifying the viscoelastic behaviour of materials. In this work various coating solutions are investigated in order to estimate their contribution to the dissipative behaviour of mechanical components. Different production processes are used to apply single-layer and dual-layer coatings of Al oxide, Ti and TiO2 , Cr and CrN to uncoated specimens made of Al, stainless steel and harmonic steel. Force and displacement experimental data obtained from forced excitation dynamic mechanical measurements are used to find the specimen constitutive equation estimated parameters. A high order generalized Kelvin model is adopted to model the constitutive equivalent material relationship of coated specimens in the form of the ratio of two polynomials expressed as a function of frequency. The model parameters are numerically identified and the model reduced and optimized by means of a robust identification technique.