Optimization of the damping properties of CFRP laminates with embedded viscoelastic layers

This paper addresses the problem of improving the loss factor of carbon-epoxy laminates with embedded viscoelastic layers. A cork based agglomerate was elected as viscoelastic material due to its low weight combined with excellent damping properties, showing a great potential for vibration control. A micro-sandwich type geometry was adopted as this provides a good compromise between structural efficiency and easiness of inclusion of the damping material. A numerical model was developed in order to obtain the best material configuration in terms of its damping response. Distinct design variables were considered to assess their influence in the loss factor variation, namely: damping layer thickness and its relative position within the laminate, number of viscoelastic layers and effect of different layup stacking sequences. Numerical results were compared with experimental data as this was a determinant step to obtain accurate computational models regarding the different types of geometries. Results are encouraging for the possible use of cork based composites as a viable passive solution to improve the damping properties of high performance composites, giving rise to an increase of the loss factor as well as a change of the natural frequencies of the structure according to the design requirements for particular applications.