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Stress-intensity factors for surface cracks in functionally graded materials under mode-I thermomechanical loading. (English) Zbl 1075.74535
Summary: This paper describes the development and application of a general domain integral method to obtain \(J\)-values along crack fronts in three-dimensional configurations of isotropic, functionally graded materials (FGMs). The present work considers mode-I, linear-elastic response of cracked specimens subjected to thermomechanical loading, although the domain integral formulation accommodates elastic–plastic behavior in FGMs. Finite element solutions and domain integral \(J\)-values for a two-dimensional edge crack show good agreement with available analytical solutions for both tension loading and temperature gradients. A displacement correlation technique provides pointwise stress-intensity values along semi-elliptical surface cracks in FGMs for comparison with values derived from the proposed domain integral. Numerical implementation and mesh refinement issues to maintain path independent \(J\)-values are explored. The paper concludes with a parametric study that provides a set of stress-intensity factors for semi-elliptical surface cracks covering a practical range of crack sizes, aspect ratios and material property gradations under tension, bending and spatially-varying temperature loads.

74G70 Stress concentrations, singularities in solid mechanics
74R10 Brittle fracture
74F05 Thermal effects in solid mechanics
74E05 Inhomogeneity in solid mechanics
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