抄録
Boilers and pressure vessels are used extensively in chemical plants. But we need to investigate safety of the boilers and pressure vessels, which are used for a long time and affected by the deterioration. Therefore in this study, the effects of local wall thinning on strength and fracture behaviors of boilers and pressure vessels were investigated. Fracture strengths of local wall thinned pressure vessels were calculated by elasto-plastic analysis, using finite element method. And we simulated various types of local wall thinning that can occur on pressure vessel's surface. The configurations of the eroded area were l =30∼400mm in diameter and d =0. 9∼4. 9mm in thickness. We investigated the internal pressure of allowable stress initiation, yield stress initiation, plastic collapse initiation and crack initiation for the effects of strength and fracture behaviors. Failure mode map was constructed for boilers and pressure vessels based on the results of element analyses in order to investigate the effect of failure behaviors.
