Study on cracked plates, shells and three dimensional bodies

Stress-intensity factors for surface cracks in functionally graded materials under mode-I thermomechanical loading

“…(36) and (45) for 3-ring and 10-ring crack-front mesh refinements where a=c ¼ 2 and a=t ¼ 0:8. interior of the specimen. Chuntu and Yingzhi (1987), Li et al (1998), Rajaram et al (2000), Ayhan and Nied (2002) and Frangi (2002) also demonstrate the localized influence of the boundary layer on stressintensity factors through numerical analyses of straight cracks and semi-circular, quarter-circular and semi-elliptical surface cracks. Nakamura and Parks (1988) estimate the region of influence of the corner singularity in semi-elliptical surface cracks as % 0:03 Â a 2 =c, where a and c are the crack dimensions shown in Fig.…”

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“…The elastic modulus function form of FGMs is assumed to be (2) (1) (1) sin y r E E e E e β β θ = = (1) where, (1) E is the elastic modulus of homogeneous material, and 0 β ≥ are the non-homogeneity parameter. The variation of Poisson's ratios has very insignificant effect on the stress intensity factor of non-homogeneous materials [4].…”

“…Actually, the inner crack in a shell structure always leads to its failure, so the security assessment in engineering has attracted the great public attention. Before, Kirchhoff's theory is mainly adopted in fracture studies of shells, including various spherical shell, cylindrical shell and so on [2]. However, this theory will lead to several problems like the difference of stress singularity, and the difference of stress argument.…”