혼합모드 부하조건에 의한 고무변성 에폭시수지의 파괴거동

Abstract

Recently, structural adhesives and fiber composites have been largely used in many structural components. Rubber-modified epoxy resins are employed as adhesives and matrix materials for various engineering components. This study is focused on the relationship between fracture toughness and damage zone size around the crack tip of rubber-modified epoxy resin under mixed mode conditions. Fracture toughness(KIC) and fracture energy(GC) are evaluated using the end notched circle type(ENC) specimens. The damage zone and rubber particles distributed around the crack tip of damaged specimens are also observed by an optical microscope. It is concluded that GC of rubber-modified epoxy resin is closely related to the area of the damage zone. The rubber particles are deformed elliptically due to the difference in principal stresses in the case that the loading angle is 30 degree