Assistant professor of mechanics, Drexel University, Philadelphia, Pa.
Pages: 13 Published: Jan 1974
Advanced fiber composite materials exhibit elastic properties and fracture mechanisms distinctive from metals. Consequently, the mechancis of impact resistance are also different for these materials. Carbon-epoxy and boron-epoxy composites can exhibit brittle modes of fracture. In studies to improve the impact resistance of carbon-epoxy materials, traditional impact tests provided very little understanding of the problems involved. However, instrumented Charpy-type tests provided considerable insight into the mechanisms associated with impact resistance. Load versus time response records can be partitioned into regions corresponding to events occuring sequentially in time. Energy absorbed by a composite specimen through the various fracture mechanisms is seen to be the distinguishing characteristic between composite systems. Two mechanisms to improve the carbon-epoxy system's impact resistance are shown to be the modification of the fiber-resin interfacial strength and hybridization with a second fiber of high strength and lower modulus.
composite materials, carbon, glass, fracturing, impact strength, epoxy resins, impact tests
Paper ID: STP32189S