Static Tensile Strength Evaluation of Notched Coeposite Materials

J. Ocean Eng. Technol. 1993;7(2):19-29.

노치를 갖는 복합재료의 정적강도평가(I)

김윤해,김영식,서곡홍신

한국해양대학교 재료공학과,한국해양대학교 재료공학과,일본구주대학

Keywords: Tensifle Property, Composite Material, Fracture Cirterion, Notched Body, Linear Notch Mechanics

핵심용어: 인장특성, 복합재료, 파괴조건, 노리채, 선형노치역학

Abstract

The static tensile tests of GFRP, ID300, CFRID300 and CFRPEEK were made on the plain and notched specimens at room temperature. The results were discussed based on linear notch mechanics which was proposed by H.Nistani. The fracture of notched GFRP, ID300, CFRID300 and CFRPEEK specimens is controlled by the elastic maximum stress, $({sigma}_max)$, and the notch root racius,$ ho$, alone, independently of the other geometrical conditions. The relation between fracture nominal stress,$({sigma}_max)$, and stress concentration factor, $K_t$ and a part where $({sigma}_c)$ is nearly constant independent of $K_t$. A similar phenomenon can be seen in the fatigue tests of notched specimes under rotating bending or push-pull. The almost constant $({sigma}_c)$ values correspond to the nearly constant apparent stress intensity factor, $K_{1pc}$ values, obtained by assuming ,$ ho$=0. This can be attributed to the existence of the stable crack. Linear notch mechanics is very useful for analyzing the static tensile fracture behavior of notched GFRP, ID300, CFRPEEK specimens.