Showing papers in "Engineering Fracture Mechanics in 2018"

TL;DR: In this article, the authors investigated the effect of water content on quasi-static fracture behavior of sandstone and found that both the fracture toughness and crack propagation velocity observably decreased with the increase of water contents.

TL;DR: In this article, uniaxial compression experiments were performed for sandstone specimens with different flaw inclinations varying from 0° to 90°, and four kinds of infilling conditions, including no filler, gypsum filler, cement filler, and resin filler were considered.

TL;DR: In this article, a collaborative localization method using analytical and iterative solutions (CLMAI) was proposed, which combined with the arrivals of multi-sensor and inversion of the real-time average wave velocity, to seek the optimal locating results.

TL;DR: In this paper, a variational fatigue phase-field model is proposed, where the fracture energy decreases as a suitably defined accumulated strain measure increases, which is obtained by introducing a dissipation potential which explicitly depends on the strain history.

TL;DR: In this paper, a phase-field regularized cohesive zone model (CZM) was proposed for both brittle fracture and cohesive failure within the framework of the unified phase field damage theory.

TL;DR: In this article, a comparison study on brittle and ductile laboratory rock-like specimens that contain nine pre-existing flaws subjected to uniaxial compression is conducted, and the fractal dimension estimation method is introduced to quantitatively track the fracture process.

TL;DR: In this article, the effects of temperature and loading rate on the dynamic fracture behavior of granite under a given preload were studied, and the results showed that the fracture toughness increases linearly with the loading rate after the same heat treatment, and decreases with increasing treatment temperature in general under the same loading rate, although fracture toughness values of heat treatment at 100-200°C and 400-600°C are very close to each other.

TL;DR: In this paper, the authors present experimental results on the anisotropy of the fracture toughness, Brazilian tensile strength, and the fracture process zone (FPZ) in granodiorite samples.

TL;DR: In this article, a computational framework for multiaxial fatigue analysis of compressor discs is established by coupling finite element (FE) simulation of stress gradient with Fatemi-Socie (FS) criterion.

TL;DR: In this article, the effect of viscoelastic asphalt characteristic on mixed mode I/II fracture resistance was investigated for hot mix asphalt (HMA) concretes in moderate service temperatures.

TL;DR: In this paper, the dynamic fragmentation of granites at strain rates of 40-150/s is explored by using SHPB apparatus and two mechanical classes (i.e., class I and class II) are observed from the stress vs. strain curves in high strain rate loading and the transition strain rate separated the two regimes is about 80/s.

TL;DR: In this paper, the influence of various parameters of the global and local weld geometry as well as material defects on the fatigue strength of weldments is investigated. And the results are in line with literature data and reveal the potential of the theoretical approach to predict the correct trends.

TL;DR: In this paper, a discussion of fracture mechanics-based fatigue considerations for the S-N curve approach to the total lifetime of weldments is presented, and possible solutions for the multiple crack problem at stress levels higher than the fatigue limit are discussed.

TL;DR: In this article, a new damage model was proposed in the bond-based peridynamics (BBPD) frame to quantitatively investigate mode-I crack propagation in concrete, which was established based on the pattern of bilinear softening curve commonly used in the discrete cohesive zone model (CZM).

TL;DR: In this paper, metallurgical factors play a major role in Hydrogen Induced Cracking of flat rolled steels commonly used in manufacturing of pipelines and pressure vessels in oil & gas industry as found in several studies.

TL;DR: In this article, the authors used uniaxial compression to measure the strength of a given rock mass under different stress levels and temperatures, and found that once the mass is subjected to higher thermal stresses, strength characteristics are significantly reduced, mainly due to thermal damage of mineral particles.

TL;DR: In this paper, a three-dimensional fracture model was developed to simulate the interactions between vertical/slanted hydraulic fractures and frictional discontinuities (such as natural fractures or horizontal/oblique bedding plane segments) with non-orthogonal approach angle.

TL;DR: In this article, the authors give an overview on the state-of-the-art on cyclic R curves and discuss the experimental determination on the one hand and questions of its application on the other hand.

TL;DR: In this article, a 3D numerical model was developed by inserting cohesive elements into finite elements to investigate the rock fracture, penetration force, and chip shape during rock breaking with a conical pick.

TL;DR: In this article, an effective measuring method of the dynamic mode I fracture toughness of high-temperature rocks, combined with laboratory tests with the Discrete Element Method (DEM), is proposed.

TL;DR: In this paper, the authors explored the mechanical properties and cracking behaviors of specimens with a hole under uniaxial compressive loading through laboratory experiments, and the results demonstrate that the shape of hole has a considerable impact on the uniao-ial compression strength and failure mode but minimal effects on the elastic modulus.

TL;DR: In this paper, a generalization of the original bond-based and ordinary state-based peridynamic models to permit the use of irregular non-uniform domain discretizations is presented, in which the strain energy and thermal potential associated with a bond between two material points are split into two parts based on volumetric ratios.

TL;DR: In this article, the authors provide an overview on the issue mainly from the point of view of the application of fracture mechanics to the determination of the fatigue strength as the topic of this special issue.

TL;DR: In this article, a triaxial compression test was carried out on sandstone specimens containing two pre-existing three-dimensional (3D) flaws to better understand the mechanical, acoustic and failure behaviors of sandstone in deep saline aquifers.

TL;DR: In this article, a bond-based peridynamic (PD) model for functionally graded materials (FGMs) was introduced to simulate various dynamic brittle fractures in FGMs, and the results of two convergence studies under uniform grid refinement (m-convergence) and decreasing radius of PD horizon (δ-consistency) were presented.

TL;DR: In this article, the effects of thermally grown oxide swelling, creep, and interfacial roughness were taken into account, and the effect of the interfacial cracking on top coat cracking and their mutual interaction were investigated using the cohesive zone model.

TL;DR: In this article, the influence of pre-existing fissure geometry parameters (various dip angles, lengths, widths, and numbers) on the mechanical properties and deformation failure modes of low-strength rock samples was investigated.

TL;DR: In this paper, the authors used peridynamics in conjunction with newly introduced peridynamic differential operator concept used to convert partial differential equation into per-idynamic form for the diffusion equation.

TL;DR: In this paper, a two-dimensional particle flow code (PFC2D) was used to simulate sandstone containing a single oval flaw under uniaxial compression, and the simulated results are in good agreement with the experimental results.

TL;DR: In this article, a stepwise fatigue assessment framework composed of safe life as the first level and damage tolerance as the second level was tentatively proposed for the wheelset with inside axle boxes.