Abstract In this contribution, a novel framework for simulating mixed-mode failure in rock is presented. Based on hybrid phase-field model fracture, separate variables are introduced tensile (mode I) and shear II) fracture. The resulting three-field problem features length scale parameters mode I II cracks. contrast to the classic two-field approaches, it can thus account different strength of ...

In this paper, we’ll answer several abstract, formal questions about the nature of crack growth and nucleation. Bringing a field theory point of view to fracture illuminates things in what I hope will be an entertaining way. Formally, what is the crack nucleation rate? Fracture is an instability of elastic theory under tension. For thermally nucleated cracks, there is an analogy with supercoole...

This work included two separate studies; the common theme in each was the use of mode-I fracture testing to evaluate wood adhesion. In the first study, mode-I fracture testing was used to compare the thermal stability of polyurethane (PUR) and resorcinol-formaldehyde (RF) wood adhesives. Bonded specimens for both adhesives were subjected to prolonged thermal exposure, and fracture testing was s...

an epoxy resin was modified by silica nanoparticles and cured with an anhydride. the particles with different batches of 12, 20, and 40 nm sizes were each distributed into the epoxy resin ultrasonically. electron microscopy images showed that the silica particles were well dispersed throughout the resin. tensile test results showed that young’s modulus and tensile strength increased with the vo...

An assessment is made here of the role played by the micropolar continuum theory on the cracked Brazilian disc test used for determining rock fracture toughness. By analytically solving the corresponding mixed boundary-value problems and employing singular-perturbation arguments, we provide closed-form expressions for the energy release rate and the corresponding stress-intensity factors for bo...

It is generally accepted that residual stresses present in welded joints alter the conditions for fracture initiation by contributing to the crack-driving force. In this study, it is shown that weld residual stresses also alter crack-tip constraint, affecting fracture in an additional way. The fracture behavior of two crack geometries, a large pressure shell and a small fracture specimen, both ...

Motivated by the inadequacy of conducting atomistic simulations crack propagation using static boundary conditions that do not reflect movement tip, we extend Sinclair's flexible condition algorithm [J. E. Sinclair, Philos. Mag. 31, 647 (1975)] and propose a numerical-continuation-enhanced scheme, enabling full solution paths for cracks to be computed with pseudo-arclength continuation, present...

Turon’s methodology for determining optimal analysis parameters for the simulation of progressive delamination is reviewed. Recommended procedures for determining analysis parameters for efficient delamination growth predictions using the Abaqus/Standard cohesive element and relatively coarse meshes are provided for single and mixed-mode loading. The Abaqus cohesive element, COH3D8, and a user-...