Showing papers in "Engineering Fracture Mechanics in 2007"

TL;DR: In this paper, a methodology to determine the constitutive parameters for the simulation of progressive delamination is proposed, which accounts for the size of a cohesive finite element and the length of the cohesive zone to ensure the correct dissipation of energy.

TL;DR: In this paper, the concept of representative volume element (RVE) is analyzed for elastic materials and the results were based on a statistical analysis of numerical experiments, where tests have been performed on a random heterogeneous material.

TL;DR: In this article, the acoustic emission technique is applied to identify defects and damage in reinforced concrete structures and masonry buildings and a particular methodology has been put forward for crack propagation monitoring and damage assessment, in structural elements under service conditions.

TL;DR: In this paper, Monte Carlo simulations on the basis of the standardised testing procedure (30 specimens) clearly reveal that these deviations can be hardly detected on a basis of small samples and that testing specimens with different volumes may help to understand the real strength distribution.

TL;DR: In this paper, the use of digital image correlation (DIC) as a fracture mechanics tool is described, for two projects currently underway, one of which is to examine the bond between carbon fiber reinforced polymers (CFRP) and concrete substrates.

TL;DR: In this article, the authors present a numerical implementation of cohesive crack model for the analysis of concrete fracture based on the strong discontinuity approach, where a simple central force model is used for the stress vs. crack opening law.

TL;DR: In this paper, a three-dimensional damage model with induced damage anisotropy is proposed for quasi-brittle materials such as concrete, where the thermodynamics framework is used, considering then a single secondorder tensorial damage variable whatever the intensity and the sign of the loading.

TL;DR: In this paper, a method for evaluating mode I, mode II and mixed-mode stress intensity factors from in-plane displacement fields using the method of nonlinear least squares is proposed.

TL;DR: In this paper, a series of investigations on the effect of fiber reinforcement on the response of structural members in direct tension and flexure under reversed cyclic loading conditions is described. And the synergistic effects of composite deformation mechanisms in the ECC and structural members subjected to large shear reversals are identified.

TL;DR: In this article, a multistage fatigue model for high cycle fatigue of a cast aluminum alloy was modified to consider the structure-property relations for cyclic damage and fatigue life of a high strength aluminum alloy 7075-T651 for aircraft structural applications.

TL;DR: In this paper, an estimation procedure to determine J-resistance curves for pin-loaded and clamped SE(T) fracture specimens using the unloading compliance technique and the η-method is presented.

TL;DR: In this paper, the fracture behavior and toughening mechanisms of PLLA/PCL blends with different PCL contents were developed, and the critical energy release rate at crack initiation, Gin, was then measured to assess the effect of PCL content.

TL;DR: In this paper, the influence of the width of carbon fiber reinforced polymer (FRP) sheets on the load-carrying capacity was investigated using a full-field optical technique known as digital image correlation.

TL;DR: In this article, the authors examined the distribution of fibres in beams, cylinders and strips of the reinforced cementitious composite CardifRC and used them to retrofit damaged concrete beams which are subjected to thermal cycling.

TL;DR: In this paper, the authors derived a quantitative index of blade sharpness via indentation experiments in which elastomeric materials are cut using both sharp and blunt straight edge blades, and found that the depth of blade indentation required to initiate a cut or crack in the target material is a function of the condition or sharpness of the blade's cutting edge.

TL;DR: An approach for real-time imaging of trabecular bone during compression using high-speed photography is presented and the hypothesis whether the whitening of deformedtrabeculae is due to microdamage is investigated, which provides a correlation to recorded stress strain curves.

TL;DR: In this paper, a multiscale model for cement-based materials focusing on the prediction of autogenous shrinkage deformations is presented, which is associated with the internal volume reduction of the cement/water mixture in the course of the hydration process.

TL;DR: In this article, the difference in behaviour of spherical and plate-like particles is reviewed, and it is shown that soft or hard spherical particles can toughen semicrystalline polymers, but platelike nanoclay particles have not produced significant toughening action and frequently cause significant embrittlement.

TL;DR: In this article, the effect of combined pulling/peeling on fiber reinforced plastics debonding was studied using a novel experimental set-up, using a set of parameters obtained from two of the specimens, the model was able to describe the debonding behavior of FRP for various specimens under various degrees of peeling effect.

TL;DR: In this paper, an overview is presented of recent results obtained in a comprehensive research (in progress) on the relation between manufacturing processes, fiber anisotropy and fracture properties of hybrid fiber concrete containing three different types of steel fibres.

TL;DR: The size effect on strength of cementitious materials was studied successfully many years ago by a crack-bridging model through detailing the influence of the resistance R-curve behavior on quasi-brittle fracture.

TL;DR: In this article, the authors developed a method coupling the finite element method (FEM) and the scaled boundary finite element (SBFEM), which is capable of fully-automatically predicting both satisfactory crack trajectories and accurate load displacement relations with a small number of degrees of freedom.

TL;DR: In this article, the effects of strength and toughness on the delamination of beam-like geometries have been studied using cohesive-zone models, and the role of modulus mismatch has been shown to influence the strength of an interface.

TL;DR: In this article, a description of the background to the essential work of fracture (EWF) test method and its relation to J tests is given and the scheme used in the proposed standard is outlined including various constraints which have evolved during the round-robin testing exercise.

TL;DR: In this paper, a two-scale procedure is outlined in order to infer an equivalent macroscopic cohesive crack law from the meso-level response of the lattice model.

TL;DR: In this article, a sequential multiscale approach is applied to model fracture in high performance fiber reinforced cementitious composites, where dominant substructures and associated physical mechanisms of deformation are identified and appropriate analytical/numerical model is formulated.

TL;DR: In this paper, a three-dimensional elasto-plastic finite element model was used to calculate stress intensity factors in wheels, in which a sub-modeling technique was employed to achieve both computational efficiency and accuracy.

TL;DR: In this paper, a probabilistic approach is used to calculate the effective number of fibers across the crack faces and calculate the probability of non-pullout failure of fibers, which can be efficiently used to predict the load-deflection behavior, moment-curvature relation and load-crack mouth opening displacement (CMOD) relation of synthetic fiber reinforced concrete beams.

TL;DR: In this paper, the size effect on the specific fracture energy of concrete can be adequately modelled by an uneven fracture energy distribution along the crack path induced by the specimen boundary influence.

TL;DR: In this paper, the authors investigated the fatigue behavior of AA2024-T3 friction stir welded overlap joints produced at German Aerospace Center (DLR) of Cologne (D), where two crack-like unwelded zones are present at overlap ends.