Computation of residual stresses for a repair weld case

Abstract

The target of EU FP7 STYLE project BStructural integrity for lifetime management -non-RPV componentŵ as to improve and unify the methods of a structural integrity assessment in the ageing and lifetime management of reactor coolant pressure boundary components. One of the mock-ups in the project was manufactures from two pipes welded together. After completion of the girth weld, a deep weld repair was inserted into the girth weld. As a part of the work, roundrobin finite element computations were performed to determine residual stresses after repair welding and the computational results were compared to the deep hole drilling measurements. In this paper, the details and recomputed results of one of the analyses is presented. A part of the input data was generated with in-house codes. Sequential thermal and mechanical analyses were performed with a small strain and displacement formulation. The comparison of computed and measured temperatures and stresses shows good agreement. The computed hoop stress at the repair mid-length was higher than the axial stress. Both stresses were tensile through the wall thickness. Confidence in the results was also gained as the results were compared to those presented in the literature for a repair welding case.

Thermomechanical Modeling of Welding and Galvanizing a Steel Beam Connection Detail to Examine Susceptibility to Cracking

“…Although the maximum value increased, the magnitude of the increase did not reflect the overall change of PEEQ during the hot-dip galvanizing process. From dwelling to postgalvanizing cooldown, the change in PEEQ was small, as shown at t 8 -t 11 . In general, the hot-dip galvanizing process produced smaller plastic strains on the beam than the welding process, although the additional plastic strains could still play an important role regarding the critical condition of the as-welded detail.…”

“…The calculated temperature fields were then imposed on the beam section to calculate stress and strain fields. This sequential modeling approach has been used widely to simulate welding processes in the literature, including studies performed by Deng and Murakawa [9], Perić et al [10], and Keinänen [11]. This approach provides the opportunity to study the influence of welding parameters (and the ensuing residual stresses and strains) on stress and strain responses during and after galvanizing.…”