Investigation of Dynamic Properties of Hybrid Laminate Structure

Current research on carbon fibre reinforced plastics (CFRP) shows an evident progression not necessarily only in the field of aerospace industry. With their inherent superior specific strength and stiffness, CFRP offer an interesting option also for various machine tool components manufacturing. CFRP are generally weak in material damping. Nevertheless, this dynamic nature of CFRP parts can be successfully improved on the basis of so-called synergistic effect by the integration of particular damping layers made of rubber or cork composition. However, these additive layers can adversely influence strength and stiffness of resulting hybrid structure. This paper deals with finding of optimal lay-up of wound square tube consisting of CFRP layers with high modulus fibres and cork composition layers. For this purpose, the Pareto optimization of the square tube was performed using three-dimensional numerical simulations. The aim was to maximize the static bending stiffness, the natural frequency and the damping ratio. The theoretical studies were followed by experimental determination of dynamic characteristic of two selected specimens using impact hammer modal testing (IHMT) method and the results were compared.