A.N. Norris and J.D. Achenbach The Technological Institute Northwestern University Evanston, IL 60201 Crack diffraction in a transversely isotropic material is analyzed. The solution is given for the diffracted field generated by incidence of a plane time-harmonic wave on a semiinfinite crack located in a plane normal to the axis of symmetry of the material. The exact solution is obtained by Fo...

A line integral is exhibited which has the same value for all paths surrounding the tip of a notch in the two-dimensional strain field of an elastic or deformation-type elastic-plastic material. Appropriate integration path' choices serye bOlh to relate Ihe integral to the near tip deformatiot~s and, in many cases. to permit its direct e:tlalutllion. This (l.t'eraged measure of the near tip fie...

A method of analysis for determining crack propagation loads on wood beams with end splits is presented. The method is based on (1) linear elastic orthotropic fracture mechanics concepts, (2) theory of complex variables, and (3) least squares boundary value collocation (BVC). Using this method, the critical stress intensity factor, Kllc of Douglas-fir beams with end splits is determined to be 2...

On the ground of manufacturing, sheet metal parts play a key role as they cover about half of the production processes. Sheet metals are commonly obtained from rolling and forming processes which causes misalignment of micro structure resulting obvious anisotropic characteristics and micro cracks. Presence of micro cracks poses serious attention, when stresses at the tip reach to the critical v...

We have considered a semi-infinite crack embedded in a transversely isotropic medium and studied two special cases, one, in which the axis of symmetry is normal to the crack face and the wave incidence is arbitrary and another, in which the axis lies in the crack plane normal to the edge and the incident wave vector is also normal to the edge. The problem is of interest in Non-Destructive Evalu...

In this paper, the fatigue and fracture properties of bovine dentin are evaluated using in vitro experimental analyses. Double cantilever beam (DCB) specimens were prepared from bovine maxillary molars and subjected to zeroto-tension cyclic loads. The fatigue crack growth rate was evaluated as a function of the dentin tubule orientation using the Paris law. Wedge-loaded DCB specimens were also ...

Asymptotic near-tip fields are analyzed for a plane strain Mode I crack propagating dynamically in non-associative elastic–plastic solids of the Drucker–Prager type with an isotropic linear strain hardening response. Eigen solutions are obtained over a range of material parameters and crack speeds, based on the assumption that asymptotic solutions are variable-separable and fully continuous. A ...

-Properties of elastic solutions to interface crack problems are discussed in both the open formulation, in which the crack faces are assumed to be traction-free and interpenetration is permitted, and the unilateral formulation, where a contact zone is generally established adjacent to the crack tips. It is shown that if the contact zone is sufficiently small compared with the other dimensions ...

In this paper the line-spring model developed by Rice and Levy is used to obtain an approximate solution for a cylindrical shell containing a part-through surface crack. It is assumed that the shell contains a circumferential or axial semi-elliptic internal or external surface crack and is subjected to a uniform membrane loading or a uniform bending moment away from the crack region. To formula...

that varies with distance, r, from the crack tip as r 1 2 . In this paper, a traction free plane stress wedge with a discrete cohesive zone along the intended crack-path is studied. Of interest is the in uence of the cohesive zone on the crack tip stress eld. Further, the in uence of the cohesive zone on the strain energy release rate is also investigated. Two example problems are studied; a do...