Solutions and applications of fracture properties for clamped single edge notched tensile specimen of orthotropic materials

Abstract

AbstractClamped single edge notched tensile (SENT) specimens are widely used in fracture toughness test and fatigue crack growth experiment of structural materials. However, the existing fracture parameters of clamped SENT specimens are all based on isotropic conditions, which limits the application of anisotropic materials. In this study, a systematic finite element analysis of orthotropic clamped SENT specimens was carried out to determine the stress intensity factor (K) and compliance (C). A wide range of orthotropic and geometric parameters, including crack length over width ratio (a/W), daylight to width ratio (H/W), and material parameters λ and ρ, were considered. The coupling effects of material parameters and geometrical dimensions on fracture properties were then investigated. Results showed that the K and C increase with the increase of a/W and H/W, and decrease with the increase of λ and ρ. The value of C is more sensitive to changes of orthotropic and geometric parameters than the K. Moreover, the accurate solutions for normalized K, C and compliance‐based crack length prediction were developed. Applications of the proposed solutions on experimental data were presented and discussed. The current results will help to accurately calculate the fracture toughness or FCG rate of composites, further advancing the standardization process of composites testing based on SENT specimens.Highlights Evaluate the K and Compliance for orthotropic single edge notched tensile (SENT) specimens using 2D finite element analysis; The coupling effects of orthotropic parameters and geometric sizes are studied; Develop prediction equations for K and C of clamped SENT specimen; Propose a universal crack length estimation method based on the compliance; Discuss the application of the proposed equations to the tested data of UD CFRP.