Ceramic–polymer composites with improved dielectric and tribological properties for semi-active damping. (April 2015) - Ginés, R.
Abstract: A heterogeneous system with enhanced dielectric and tribological properties is developed for an electrostatic tuneable friction damper. Such system consists of a carbon fibre reinforced polymer stiffening element which is reversibly laminated onto a host structure by means of electrostatic fields. Damping is achieved when the maximum shear at the interface between stiffening element and structure exceeds the shear strength of the electrostatically laminated interface. The permittivity of the composite material, consisting of barium titanate particles in an epoxy matrix, follows the logarithmic mixing rule formulated by Lichtenecker. In order to exploit the beneficial effect of the high-permittivity filler material, a particle concentration of at least 30 % by volume is necessary. To improve the reduced wear resistance caused by the addition of such filler material, ceramic platelets are introduced and magnetically aligned. This measure reduces the wear volume by more than 70 % without affecting significantly its coefficient of friction. By increasing permittivity and the static friction coefficient, the required force to achieve damping can be realised at lower electric fields compared to commercially available polymer films.