Assessment of the drum remaining lifetime in thermal power plant

Abstract

In this paper analysis of stress and thermal-elastic-plastic strain of the drum is performed. Influence of modified thickness, yield stress and finite element model of welded joint between pipe and drum on assessment of the remaining lifetime of the drum in the thermal power plant is analyzed. Two analyses are compared. In the first, drum is modeled by shell and by 3-D finite elementswithprojected geometrical and material data of drum. Then, the drum is modeled by shell and by 3-D finite elements with modified thickness and yield stress. The analysis show that detailed modeling of stress concentration zones is necessary. Adequate modeling gives lower maximal effective plastic strain and increased number of cycles and, in that case,3-D finite elements are better comparingto shell finite elements.