임계정류피로크랙의 하한계 전파조건의 정량적 고찰

• 영문명: Quantitative Study on Threshold Condition of Critical Non-propagating Crack
• 발행기관: 강원대학교 산업기술연구소
• 저자명: 김민건(Kim, Min-Gun)
• 간행물 정보: 『산업기술연구』vol.30, 17~24쪽, 전체 8쪽
• 주제분류: 공학 > 공학일반
• 파일형태: PDF
• 발행일자: 2010.09.30

영문 초록

Since the propagation of a short fatigue crack is directly related to the large crack which causes the fracture of bulk specimen, the detailed study on the propagation of the short crack is essential to prevent the fatigue fracture. However, a number of recent studies have demonstrated that the short crack can grow at a low applied stress level which are predicted from the threshold condition of large crack. In present study, the threshold condition for the propagation of short fatigue crack is examined with respect to the micro-structure and cyclic loading history. Specimens employed in this study were decarburized eutectoid steels which have various decarburized ferrite volume fraction. Rotating bending fatigue test was carried out on these specimens with the special emphasis on the critical non-propagating crack length It is found that the reduction of the endurance limit of their particular micro-structures can be due to the increase of the length of critical non-propagating crack, and the quantitative relationship between the threshold stress σwo and the critical non-propagating crack length Le can be written as σwo m ㆍLc=C where m, C is constant. Further experiments were carried out on cyclic loading history on the length of critical non-propagating crack. It shown that the length of critical non-propagating crack is closely related to cyclic loading history.

목차

1. 서론

2. 시험편 및 실험방법

3. 결과 및 고찰

4. 결론

키워드

피로크랙 임계정류크랙 하한계 전파조건 fatigue crack critical non-propagating crack threshold condition