71 Damage Absorption of High-Impact Structural Systems using Time-Reaction of Hybridized Epoxy-Polyurea Interfaces

This study investigates the optimum design in terms of the minimum cost of A carbon-fiber reinforced hybrid-polymeric matrix (CHMC) composite was developed for vibration suppression applications, where the hybrid matrix system was created by combining two polymeric compounds - the epoxy-based phase I which has highly crosslinked morphology and the lightly-crosslinked polyurea elastomeric phase II which when reacted with curing phase I, provides high damping and fracture toughness. The chemical reactions incurring the hybrid matrix system are discussed. The microstructures and micromechanical properties of CHMC are examined through scanning electron microscopy and nanoindentation. Dynamic properties of CHMC as well as conventional carbon-fiber reinforced epoxies are investigated using free vibration and randomly excited vibration tests, and test results indicate CHMC exhibits significantly greater damping than carbon-fiber/epoxy. The influence of two material processing parameters - the polyurea thickness hp and elapsed curing time tc of epoxy - on material damping is investigated. Generally, damping coefficients increase with greater hp and smaller tc.