# 평직복합재의 노치강도 및 피로특성에 미치는 보조원공의 영향

• 김정규 (한양대학교 기계공학부) ;
• 심동석 (한양대학교 대학원 기계설계학과) ;
• 한민규 (만도기계(주) 평택사업본부.연구소)
• Published : 1997.11.01
• 43 3

#### Abstract

The relaxation of stress concentration in notched members can be very significant in the improvement of notched strength and fatigue life. This paper investigated the relationship of stress concentration factor, and notched strength and fatigue life. The stress concentration factors were analyzed by FEM. Uniaxial tensile and fatigue tests were carried on plain woven composite specimens which have a main hole and two defence holes. From experimental results, the notched strength and the fatigue limit increased up to about 50% and 30% respectively due to the reduction in stress concentration. The fatigue lives predicted by Juvinall's approach were underestimated than test results and this trends were remarkable as nothed strength increased. This is because of the underestimation of a coefficient. A in S-N curve (.sigma.$_{ar}$ =A $N_{f}$ $^{B}$). Therefore, considering notched strength the coefficient A was modified. The fatigue lives by this process were agreed well with the experimental results.sults.

#### Keywords

Stress Concentration Factor;Main Hole;Defence Hole;Notched Strength;Fatigue Life