STRUCTURAL THERMAL TRANSIENT NUMERICAL ANALYSIS OF RESIDUAL STRESSES IN CYLINDRICAL PRESSURE VESSELS SUBMITTED TO WELD REPAIR ACCORDING TO STANDARD ASME PCC-2-2015

Abstract

This paper presents the calculation of residual stresses present in cylindrical pressure vessels subjected to weld repairs using the ASME PCC-2-2015 via numerical multiphysical thermal structural analysis using the finite element method. The methods of analysis of residual stress by numerical analysis are increasingly part of the dynamics of structural integrity in equipment such as pressure vessels, flanges, heat exchangers, in addition to observing the behavior of these stresses in the thermally affected areas due to welding processes. In welding repair, the sleeve is attached to the pressure vessel through two longitudinal welds and two transverse welds. The modeling of the pressure vessel, repair and welding were carried out according to the aforementioned standard. The welding parameters were adopted with what happens in practice, and with that the temperature distribution and heat flow were obtained. The objectives were to analyze the longitudinal, tangential and residual stresses in the regions of the weld, pressure vessel and repair during the welding period, and to verify the behavior of these stresses after the cooling period. This work shows that numerical analysis can be used efficiently and objectively in situations of control and knowledge of the structural integrity of equipment.