Accumulated inelastic strain based damage modeling of pressure vessel steels in air

Abstract

A great deal of research is currently being conducted on methods which can lead to a more robust clean energy infrastructure. One such method is using hydrogen gas as an energy carrier to store energy during low demand and convert it to electricity when demand increases. Many of the current vessels designed to transport and store pressurized hydrogen gas are designated DOT3AA cylinders. The materials used for the construction of DOT3AA cylinders designed for hydrogen service must be qualified by use of ISO-11114 Transportable Gas Cylinder- Compatibility of Cylinders and Valve Materials with Gas Contents standard: Part 4 - Test methods for selecting steels resistant to hydrogen embrittlement. The standard uses three disparate methods to certify materials for this use. This work creates a framework for modeling each of the three test methods as well as in-service conditions of a DOT3AA cylinder in the finite element platform ABAQUS. To determine the deformation response at areas of interest, a non-linear combined kinematic/isotropic hardening model has been implemented and calibrated to strain-life fatigue tests conducted in air on AISI4130 steel removed from an DOT3AA cylinder. The modeling results are used to compare each of the three test methods to in-service conditions. The resulting framework can be built upon to incorporate the effects of hydrogen and is a first step towards the ability to unify results of each test method as well as in-service conditions.