Experimental evaluation of the damping properties and optimal modeling of coatings made by plasma-deposition techniques

Coating layers, applied by means of different deposition technologies, can be used to produce composites with high damping properties. This is well known in literature and it is also verified by some experimental results reported in this work. The constitutive equivalent material model of coated specimens is identified and optimized by means of a generalized Kelvin model of n-th order, defined by means of the ratio of polynomials in the frequency domain. Dynamical measurements data obtained from coated single-layered and multi-layered samples obtained with different deposition techniques, are used to identify the optimal material model order and parameters. A robust identification technique that makes use of Forsythe orthogonal polynomials is employed for the numerical identification of the model parameters and a specific technique is introduced to eliminate the model non-physical components generated by measurement and model noise.