Modelling the test methods used to determine material compatibility for hydrogen pressure vessel service

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Mechanics

Background:

• Hydrogen gas cylinders require rigorous safety testing.
• Existing test methods (ISO 11114-4) need correlation with real-world conditions.
• Predictive modeling is crucial for assessing material integrity.

Purpose of the Study:

• To develop finite element models for ISO 11114-4 test methods.
• To calibrate constitutive and damage models for predicting material deformation.
• To correlate various test methods with in-service conditions for hydrogen cylinders.

Main Methods:

• Creation of six finite element solid models (specimens, ISO tests, cylinder).
• Calibration of monotonic and cyclic constitutive models using experimental data.
• Development and application of a novel damage parameter.

Main Results:

• The proposed damage parameter successfully correlates ISO Methods B & C and in-service conditions.
• The damage parameter predicts critical damage onset across different geometries and loads.
• Parametric studies estimate cycles to crack extension for DOT 3AA cylinders with internal cracks.

Conclusions:

• Finite element modeling with calibrated constitutive and damage models offers a robust approach.
• The new damage parameter provides a unified method for evaluating hydrogen cylinder integrity.
• This work establishes a baseline for future studies in hydrogen environments.