ReIiability Calculation for Piping Containing Circumferential Crack Based on 3-D Elastic-Plastic SFEM

摘要

In this paper, the reliability of welded pipe with circumferential surface crack was calculated by using the 3-D stochastic finite element method. This method has overcome the shortcomings of conservative results in safety assessment with deterministic fracture mechanics method. The calculation of reliability was based on 3-D elastic-plastic perturbation stochastic finite element program which was developed by ourselves. The effects of variables such as fracture toughness δ_c external load(including bending moment M and inner pressure P ) and the depth of the circumferential surface crack A on the structure reliability were also discussed. The calculation results indicate that among the four variables (δ_c, M P, A ), the bending moment M has the greatest effect on the reliability of the welded pipe. The next important influence factor is fracture toughness. The third one is the depth of the circumferential surface crack A. The inner pressure P has lower effect on the reliability of the welded pipe than both δ_c and A. The method has put forward a new way for safety assessment of welded pipe with circumferential surface crack.