Torsional impact of transversely isotropic solid with functionally graded shear moduli and a penny-shaped crack

The torsional impact response of a penny-shaped crack in an unbounded trans versely isotropic solid is considered. The shear moduli are assumed to be f unctionally graded such that the mathematics is tractable. Laplace transfor m and Hankel transform are used to reduce the problem to solving a Fredholm integral equation. The crack tip stress fields are obtained. Investigated are the influence of material nonhomogeneity and orthotropy on the dynamic stress intensity factor. The peak value of the dynamic stress intensity fac tor can be suppressed by increasing the shear moduli's gradient and/or incr easing the shear modulus in a direction perpendicular to the crack surface. (C) 1999 Elsevier Science Ltd. All rights reserved.