대변형 효과를 고려한 원주방향 관통균열 엘보우의 닫힘굽힘 한계하중에 미치는 내압 영향 평가

Effect of Internal Pressure on Plastic Limit Loads for Elbows with Circumferential Through-wall Crack under Closing Bending Incorporating Large Geometry Change Effects

Based on three-dimensional (3-D) FE limit analyses, this paper estimates effect of internal pressure on plastic limit loads for elbows with circumferential through-wall crack under in-plane bending incorporating large geometry change effects. Circumferential through-wall crack in extrados is considered. The FE limit analyses using the large geometry change option provide plastic collapse loads (using the twice-elastic-slope method). For the bending mode, closing bending is considered. Other relevant variables affecting plastic limit loads are systematically varied, related to pipe bend geometry (the mean radius, thickness and bend curvature) and defect geometry (the length of circumferential through-wall crack).