A METHOD TO ESTIMATE CROSS-SECTIONAL STRESS DISTRIBUTIONS ON REINFORCED NOZZLE CORNERS UNDER INTERNAL PRESSURE

摘要

Stress distribution through the nozzle corner cross-section may be required to calculate stress intensity factor (SIF) for a nozzle corner crack in accordance with ASME Section XI Nonmandatory Appendix G. This paper proposes a simple method to predict nozzle corner cross-section stress distributions on reinforced nozzle corners of pressure vessels under internal pressure. This method includes simplified equations for predicting stresses on the inner surfaces of the nozzle corner region. These equations are expressed in terms of stress concentration factor (SCF) and geometric variables. Approximate SCF solutions for the reinforced nozzle corners are also proposed. Stress distributions using the proposed method are compared with finite element (FE) analysis results of nozzle-vessel intersections of various geometric dimensions, and agreements are quite good within postulated crack depths. Furthermore, SIFs calculated from the estimated stress distributions in accordance with ASME Section XI Nonmandatory Appendix G are compared with those from the FE results, showing good agreement.