잔류응력으로 인한 응력비 변화를 고려한 U자형 구조의 피로특성 평가

다국어 초록 (Multilingual Abstract)

Mechanical structures with power sources experience repeated force produced by motors. As a result, the life of the pipes reduces and ultimately, the pipes collapse. In most cases, the U-shape pipe is made from a straight pipe by complicated bending work. During this work process, plastic deformation of the pipe produces residual stress in the pipe. This residual stress significantly affects the fracture behavior of the pipe and induces the change of the stress ratio (min. stress/Max. stress = R). For this reason, residual stress has to be evaluated. In this paper, the residual stress of a U-shaped pipe was evaluated by FEM analysis. In addition, fatigue tests of the U-shaped pipe were performed by using a uniaxial fatigue testing machine. The results of the fatigue test were modified with the results of FEM (Finite Element Method) analysis for residual stress. The modified fatigue test results of the U-shaped pipe were compared with those of a straight pipe.

목차 (Table of Contents)

• Abstract
• 1. 서론
• 2. 인장시험
• 3. 피로시험
• 4. 유한요소해석을 이용한 잔류응력 평가
• 5. 고찰
• 6. 결론
• 후기
• 참고문헌