The well-known J integral of elastic fracture mechanics has been related to potential energy-release rate associated with crack extension and has proved to be of great value in fracture testing. In particular, the pathindependence of the J integral has been used to an advantage in performing acoustoelastic measurements along a closed contour surrounding a crack tip. In Mode I (opening mode) for...

We present a modi cation to the quarter-point crack tip element and employ this element in two-dimensional boundary integral fracture analysis. The standard singular element is adjusted so that the near-tip crack opening displacement satis es a known constraint: the coe cient of the term which is linear in the distance to the tip must vanish. Stress intensity factors calculated with the Displac...

We present a modification to the quarter-point crack tip element and employ this element in two-dimensional boundary integral fracture analysis. The standard singular element is adjusted so that the near-tip crack opening displacement satisfies a known constraint: the coefficient of the term which is linear in the distance to the tip must vanish. Stress intensity factors calculated with the dis...

One of the assumptions Linear Elastic Fracture Mechanics is that crack faces are traction-free or, at most, loaded by bounded tractions. The standard Irwin’s closure integral, widely used for computation Energy Release Rate, also relies upon this assumption. However, there practical situations where load acting on boundaries singular. This case, instance, in hydraulic fracturing, fluid inside e...

Acoustic measurements, using longitudinal waves in plane specimens, based on the theory of acoustoe~asticity, permit the determination of the sum of the principal stresses (crl + cr2). By automatic scannlng, we are able to make such measurements throughout a region of interest. In this paper we shall be concerned with the application of this acoustoelastic stress analysis to fracture mechanics....

In previous studies, enamel showed indications to occlude small cracks in-vivo and exhibited R-curve behaviors for bigger cracks ex-vivo. This study quantifies the crack tip's toughness (K(I0),K(III0)), the crack's closure stress and the cohesive zone size at the crack tip of enamel and investigates the toughening mechanisms near the crack tip down to the length scale of a single enamel crystal...

This paper (Part II), which is the second in a series of two papers, presents new closed-form solutions for net-section-collapse (NSC) analysis of circumferentially cracked pipes for several idealized crack shapes subjected to combined bending and tension (pressure-induced) loads. They are based on further simpli®cations of generalized NSC equations developed in a parallel study. Analytical sol...