Vol.12, No1, 2012, pp. 31–34
 UDC 539.42

LEAK-BEFORE-BREAK ANALYSIS OF A PRESSURIZER - ESTIMATION OF THE ELASTIC-PLASTIC SEMI-ELLIPTICAL THROUGH-WALL CRACK OPENING DISPLACEMENT

Nenad Gubeljak1, Jožef Predan1, Dražan Kozak2

1)University of Maribor, Faculty of Mechanical Engineering, Maribor, Slovenia, nenad.gubeljak@uni-mb.si

2)Josip Juraj Strossmayer University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Slavonski Brod, Croatia

Abstract

The work presents methods to estimate elastic-plastic semi-elliptical through-wall Crack Opening Displacement (COD) for the Leak-Before-Break analysis of a pressurizer. Usually proposed methods are based on GE/EPRI approach or on the reference stress and J-integral as stress intensity factor (SIF) along the crack tip. J-integral calculation provides the value of SIF at each node of mesh along the crack tip, where values vary from the surface to middle section of material in respect to material properties. COD value is calculated through thickness along the centre of crack. The COD values are less sensitive to distance from crack tip and material properties. The engineering approach for the calculation of J-integral by using COD values and material full stress-strain data is given. COD values are proportional to surface length of semi-elliptical through wall crack of the pressurizer

Keywords: semi-elliptical through-wall crack, crack opening displacement, GE/EPRI approach, leak-before-break analysis, reference stress approach

full article (1046 kB)