Experimental Evaluation and Modeling of the Damping Properties of Multi-Layer Coated Composites

In this work, the dissipative properties of different coating solutions are compared and a beam mechanical model, taking into account of dissipative actions at the interface between different layers is proposed. The aim is to find optimal coatings to be employed in the production of composites with high damping properties. The investigated coating layers are obtained from different materials and production processes, and are applied on different metallic substrates. The composite specimens, in the form of slender beams, are tested by means of forced excitation dynamic measurements. Force and displacement experimental data, in a wide range of excitation frequencies, are used to estimate the system damping properties. Homogeneous, uncoated specimens are also tested for comparison. A specific identification procedure is used to identify the specimens stress-strain relationship in the frequency domain. The ratio of the imaginary part and the modulus of the specimen estimated complex frequency response function is considered as a measurement of the damping behaviour. A modified third order multi layered beam model, based on the zig-zag beam theory, is proposed. The model takes into account the contribution to the damping behaviour of the frictional actions and slipping at the interface between layers. Frictional actions are modelled by means of a complex, elasto-hysteretic contribution