PWSCC Crack Growth Analysis Using Numerical Method in the Inner Surface Repair Weld of A Nozzle

Kim, Sang-chul; Kim, Mann-won

Journal of KWJS 2011;29(2):64-71.
Published online May 7, 2011.

노즐 이종금속용접부의 내면 보수용접부에서 수치해석법을 이용한 PWSCC 균열성장해석

PWSCC Crack Growth Analysis Using Numerical Method in the Inner Surface Repair Weld of A Nozzle

Abstract

In this paper, crack propagation analyses in the inner diameter (ID) repair weld of the dissimilar metal weldment of a nozzle were performed using a finite element alternating method (FEAM). To calculate the theoretical solution for the crack tip stress intensity factor, a weak type singular integral equation consisted of crack surface traction and dislocation density function was constructed and solved in conjunction with the FEAM. A two-dimensional axisymmetric finite element nozzle model was prepared and ID repair welding was simulated. An initial crack, 10% depth of weld thickness, was assumed and crack propagation trajectory from the initial crack to the 75% depth of thickness was calculated using the FEAM. Crack growth versus time curve was also calculated and compared with the curves obtained from ASME code method. With the method constructed in this paper, crack propagation trajectory and crack growth time were calculated automatically and effectively.

Key Words: Inner diameter repair weld, Dissimilar metal weld, Crack propagation, Finite element alternating method, Weld residual stress