Nanocomposite glide surfaces for FRP hydraulic cylinders – Evaluation and test

The use of continuous fibre-reinforced plastics (FRP) can significantly reduce the mass of hydraulic cylinders, such that light-weight actuators are becoming increasingly common especially in mobile applications. Currently, metallic inner liners are used as piston glide surfaces, which are commonly subject to failure-critical stresses due to the different mechanical behaviour of FRP laminate and metal structure. Adapted polymeric nanocomposites offer great potential to counteract these deficits, based on their good wear characteristics and chemical resistance as well as their high fracture strain and layer adhesion strength appropriate for the laminate deformation. Given this background, theoretical and experimental studies are being carried out on a nanoparticle-reinforced epoxy gelcoat, which has been adapted for load and for efficient manufacturing, as a piston glide surface layer under combined tribological, mechanical and media load. To evaluate the theoretical projection of the mechanical and hygrothermal load on the nanocomposite layer, the stresses and deformations are calculated using multi-layer composite theory for thick-walled anisotropic cylinder shells, and are then compared with experimental data.