This study investigates the property of crack growth at the specimen of structural steel. The behaviour of fracture mechanics on the specimens with only a center crack and with holes existed symmetrically near a center crack is studied. The tensile load is applied on the specimens with these conditions. Stress intensity factors are obtained by the basis of these experimental values and these values are verified with the structural analysis of finite element method. As the length of center crack becomes larger in case of the specimen with holes existed symmetrically near a center crack, the values of deformation energy and stress become larger. On the contrary, the values of deformation energy and stress become smaller as the length of center crack becomes larger in case of the specimen with only a center crack. By examining the stress intensity factor in this study, this value becomes rather smaller although the length of center crack becomes larger. There is the position where crack is likely to happen or weak part at the mechanical structure or the machine. As the holes are punctured and arranged adequately near this crack or weak part by using the result of this study, the fracture due to it can be prevented.

1. 서 론
 2. 실험 방법
 3. 모델의 설계 및 해석 방법
  3.1 설계 방법
  3.2 시뮬레이션 해석 수행 방법
 4. 경계 조건 및 해석 모델의 물성치
 5. 연구 결과
 6. 해석 결과
 7. 해석과 실험에서의 응력확대계수 비교
 8. 결 론
 후 기
 References

• 이정호(Course of M. S. in Mechanicla Engineering at Graduate School of Kongju National University) | Jung-Ho Lee
• 조재웅(Member, Kongju National University) | Jae-Ung Cho Corresponding author