Modelling Fatigue Crack Growth in High-Density Polyethylene and Acrylonitrile Butadiene Styrene Polymers

Area of Science:

• Materials Science
• Polymer Engineering
• Fracture Mechanics

Background:

• Fatigue crack growth (FCG) in composites is complex.
• Previous studies utilized Simple-Scaling and Hartman-Schijve models for FCG in fibre-reinforced composites.
• These models related FCG rate to crack driving force (Δκ).

Purpose of the Study:

• To evaluate the applicability of Simple-Scaling and Hartman-Schijve methodologies for FCG in different polymer grades.
• To assess the models' ability to account for variations in FCG behavior under different test conditions.
• To extend the application of these models to polymers processed via additive manufacturing.

Main Methods:

• Analysis of fatigue crack growth (FCG) data.
• Application of Simple-Scaling methodology.
• Utilization of the Hartman-Schijve crack growth equation relating FCG rate (da/dt) to stress intensity factor range (ΔK).

Main Results:

• Both Simple-Scaling and Hartman-Schijve models successfully accounted for differences in FCG rates (da/dt) versus ΔK for high-density polyethylene (HDPE).
• The models were effective across different HDPE grades, pre- and post-electron-beam irradiation, and various R-ratios.
• FCG in acrylonitrile butadiene styrene (ABS) processed via injection molding and additive manufacturing (AM) was also successfully analyzed using these approaches.

Conclusions:

• The Simple-Scaling and Hartman-Schijve methodologies are robust for analyzing fatigue crack growth (FCG) in diverse polymer systems.
• These models provide a consistent framework for understanding FCG behavior in polymers, including those produced by additive manufacturing (AM).
• The findings support the use of these established methods for predicting FCG in various polymer applications.