A damage mechanics model under dynamic thermal loads and its application to pressure vessels under fire invasion

Abstract

The accurate prediction of pressure vessel rupture under fire invasion conditions is crucial for identifying boiling liquid expanding vapour explosions (BLEVEs). This study proposes a material damage model based on a calculus strategy to predict the evolution of material damage under dynamic thermal loads. In this model, the dynamic thermal load was differentiated, and the Gurson–Tvergaard-Needleman (GTN) model was combined with the Johnson-Cook (J-C) hardening function to calculate the damage within each differential time step. The stress update algorithm was used to calculate the cumulative damage. The damage characteristics of the materials at different temperatures were obtained, and the key parameters were identified as functions of temperature to describe the constitutive relationship during the dynamic damage process. The model was used to simulate and predict the failure morphology, failure time, and failure pressure of pressure vessels under fire invasion conditions. The results showed that it had good prediction accuracy and could be used to analyse BLEVE accidents involving pressure vessels.