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In the present study, weight functions (WFs) of a subsurface crack were derived by proposing a new general form for approximate one‐dimensional WF. The WFs coefficients were considered as a function of crack length to depth ratio and were obtained using reference stress intensity factors (SIFs) of 16 cracks under uniform, linear, and parabolic normal and shearing loadings. The verification was performed by comparison of the straight and coupled SIFs calculated by WF and finite element modelling under some complicated loadings. In conclusion, the WFs can be simply and effectively employed for evaluating the cracks under any complex stress distributions. [ABSTRACT FROM AUTHOR]

Approximate Stress Intensity Factors (SIFs) for a semi-circular surface crack in arbitrary elastic finite and infinite bodies are presented. Utilizing General Point Load Weight Function (GPLWF) concept, an explicit expression is derived to determine SIFs for semi-circular cracks subjected to uniform, linear, and nonlinear loads. The presented formulation not only provides a solution for cracked bodies subjected to arbitrary two-dimensional stress distribution on the crack faces, but also could present SIFs for any point on the crack front. The results of the presented formulation for special cases, i.e. semi-circular cracks in a finite thickness plate subjected to complicated loadings, central and non-central semi-circular cracks in finite-length thick-walled cylinders subjected to a uniform internal pressure, and central semi-circular cracks in an infinite-length thick-walled cylinder subjected to a non-uniform internal pressure are compared with the available results in the literature and those obtained through FEM, indicating a very good accuracy. The proposed procedure will be generalized for semi-elliptical cracks in arbitrary structures and mixed mode loading in future. [ABSTRACT FROM AUTHOR]

• Using 2-D WF for investigation of a fully closed 2-D subsurface crack. • Growth pattern determination for an elliptical crack under moving contact pressure. • History of SIFs calculation for subsurface cracks under subsurface shear stresses. • Validating WFM as a simple tool for the engineers to evaluate fatigue life. In the present study, weight function (WF) method was used to investigate the propagation pattern of a two-dimensional parallel subsurface crack under a moving contact pressure. Under contact loading, the crack was fully closed and only shear fracture modes led to the propagation. At first, the histories of stress intensity factors (SIFs) were calculated using the available two-dimensional WFs. Then, the SIFs range for four main points along the crack front and the Paris Law were utilized to determine step by step propagation. Results revealed WF method as an efficient method for fatigue analysis of fully closed cracks. [ABSTRACT FROM AUTHOR]