Effect of Inclined Cracks on the Fatigue and Fracture Behavior of Woven Steel/Reinforced Polyethylene Composite

Abstract

In this study, the fatigue and fracture behavior of woven steel/reinforced high-density polyethylene thermoplastic composite, having a middle tension specimen with inclined through-thickness cracks, under fatigue loading were examined. The composite material was manufactured from bidirectional woven Cr—Ni steel fibers and high-density polyethylene with a fiber volume fraction (Vf) of 0.04. The separate cracks on the sample are oriented at different angles such as 15°, 30°, 45°, 60°, and 75°. According to each crack geometry, fatigue crack growth was investigated. During the fatigue test, crack initiation, fatigue life, fatigue crack growth rate (da/dN), and stress intensity factor ranges (ΔKI, ΔK II, ΔKIeq, ΔKIIeq, and ΔKeq) were examined. In addition, strain energy release rate (ΔG) was checked out, since it was also an effective parameter in crack propagation. Crack growth rate was used as a damage parameter related to the crack geometry. In the results, crack growth rate was controlled through stress intensity factor ranges (ΔK ) and strain energy release rates (ΔG). Graphs of Δa/N, da/dN - ΔK and da/dN - ΔG such as material properties under consideration were plotted on log scale. Material constants were determined using Paris—Erdogan equation. Also, ΔG values were determined using linear elastic fracture method and compliance method, and the results were compared.