Numerical Analysis of Evaluation Criterion for Hydrogen Blistering in High-Density Polyethylene With Cavity Defect

Abstract Due to the permeability of gases, polymer materials operating under pressurized environments can permit gas molecules to penetrate their structure. During rapid gas decompression, the gas accumulated within the material often expands and diffuses outward, causing localized damage in blistering or cracking. This phenomenon compromises the material’s mechanical properties and shortens its service life. Such behavior has been widely observed and studied in rubber and plastics. To clarify the effects of the size and position of the defect, as well as hydrogen pressure on blistering formation in HDPE during the rapid gas decompression, this study conducted three-dimensional finite element simulations of the pressurization and decompression processes of HDPE disk containing pre-existing round cavity defect. The simulations quantified failure thresholds under synergistic interactions of defect geometry (size and position) and hydrogen pressure. A cavity was introduced as the initial defect in the model, and the study examined the effects of defect size, defect location, and applied pressure on the stress distribution around the defect. The results revealed the evolution of the size of the cavity and the stress distributions around the cavity during rapid gas decompression. By comparing the maximum principal stress at the defect location with the material’s yield strength, we propose an evaluation criterion that takes into account the size, location of initial defects, and hydrogen pressure at a fixed depressurization rate of 10 MPa/s, to jointly assess whether HDPE material will undergo hydrogen blistering. This approach integrates multi-parameter interactions and provides critical data support for nondestructive testing methodologies in engineering design, enabling precision defect tolerance assessments for HDPE components in hydrogen infrastructure.