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Showing 1 to 20 of 24 for “"fracture process zone"”.
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Fracture process zone : microstructure and nanomechanics in quasi-brittle materials
Cracks begin (and end) at a crack tip; the "Fracture Process Zone" (FPZ) is a region of damage around the crack tip. The context of this research is the FPZ in quasi-brittle materials, which is characterized by cracking at various scales. This study focuses on crack propagation and FPZ development …
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Effect of specimen geometry and test configuration on the fracture process zone for asphalt materials
… the symmetric axis resulting in mode-I type of fracture similar to, the typical three-point bending beam tests. The I-FIT global response refers to the load-versus-displacement curve that is characterized using the fracture energy (FE), strength, and post-peak slope. The microstructural response …
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Novel techniques for fracture monitoring in crystalline rock
The study of fracture is necessary in geotechnical engineering for the safe design of structures and application of engineering principles. Fracture plays a significant role in the behavior of rock and structures during failure. Often times, fracture processes observed in the laboratory do not …
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Micromechanical Simulation of Fatigue in Nodular Cast Iron
… as voids, and they are resolved discretely in fracture process zone. The region outside of the fracture process zone is considered as a homogenized medium. When positive alternating loads are applied, ligaments in the fracture process zone show ratchetting behavior, which is responsible for an …
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Behaviour of fracture process zones in concrete influenced by simultaneously applied normal and shear displacements
… stresses remains consiant during the entire fracture process. However, since the mid-eighties the applicability of the model has been further extended to cases where the direction of the principal stresses is changed during the fracture process. The applications of the model in these cases …
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Prediction of service load of concrete structures after cracking using ultrasonic technique
… study is to investigate the cracking behavior of fractured concrete structures and to introduce a new approach to assess their remaining service lives. A novel ultrasonic technique is utilized to detect crack propagation in notched beams of mortar, plain concrete and reinforced concrete. The study …
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Mechanisms of Ductile Fracture: Void Growth by Dislocation -Loop Emission and Hydrogen-Assisted Crack Propagation
… propagation in materials which fail by ductile processes in the presence of hydrogen. First the hydrogen effect on dislocation mobility and lattice dilatation was considered to establish the material constitutive law. Simulations in a unit cell containing a void were carried out to devise …
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Fracture Behavior of Masonry Bond
The applied fracture mechanics model, when both elastic and inelastic deformations were considered, always over-estimated the post-peak behavior. However, the post-peak behavior was successfully predicted when the model was modified to consider only elastic deformation. The analysis indicated that …
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Evaluation of viscous effects in crack tip fields in recycled asphalt pavement materials using digital image correlation
In this work, we investigated the fracture behavior of asphalt, a heterogeneous mixture of hard aggregates (usually rock) with a polymeric binder (also called asphalt), used in paving applications. Specifically we studied the dependence of asphalt fracture response on loading rate, temperature, and …
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Simulation of Fracture of Concrete Using Micropolar Peridynamics
… constitutive damage model for simulating tensile fracture of concrete using the micropolar peridynamics model. Micropolar peridynamics was proposed by Gerstle in 2007 as a generalization to the bond based peridynamics method introduced by Silling in 2000, which was only capable of handling …
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Fracture of Asphalt Concrete: A Cohesive Zone Modeling Approach Considering Viscoelastic Effects
… that exhibits time and temperature dependent fracture behavior. Softening of the material can be associated to interlocking and sliding between aggregates, while the asphalt mastic displays cohesion and viscoelastic properties. To properly account for both progressive softening and …
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Investigation of Toughening Mechanisms in the Fracture of Asphalt Concrete Using the Clustered Discrete Element Method
… of solid inclusions and a viscous matrix. The fracture of heterogeneous solids is a difficult problem to handle numerically due to the creation and continuous motion of new surfaces. A clustered discrete element method (DEM) is employed as a means to investigate fracture mechanisms in asphalt …
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Three-dimensional modeling of failure in quasi-brittle materials and structures
… and failure due to the presence of a nonlinear fracture process zone ahead of the crack front. Predictive models and design methodologies have to be able to reliably calculate the load capacity, or structural strength, of structures while taking into account the nonlinearity of the material …
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Mechanical properties and microcracking behaviour of heterogeneous rocks after high-temperature treatment
… influence of temperature on the evolution of the fracture process zone under mode I/II loading conditions. The results show that with the increase of temperature, the mechanical properties of rock (including peak load, generalized stiffness, mode I/II fracture toughness and absorbed energy) …
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Strain gradient plasticity-based modeling of damage and fracture
… Particularly, gradient-enhanced modeling of fracture and damage appears imperative - independently of the size of the specimen - as the plastic zone adjacent to the crack tip is physically small and contains strong spatial gradients of deformation. In this work a general framework for damage …
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Development of a numerical technique for modelling of multi-stage hydraulic fracturing in shale reservoirs
… (HF) stimulation. What significantly affects the fractures arrangement, and associated geometries is the stress field changes, referred to as “stress shadowing”. In this dissertation, in order to present a numerical technique, which is capable of capturing the non-planar hydraulically driven crack …
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Examination of flexural crack width prediction in concrete: comparison of analytical and numerical models
… of steel to the tension area transforms the fracture process zone problem to the definition of a bond-slip relationship. Bond stresses generated at the rebar perimeter define the analytical relationships in design codes. These stresses control crack width at the tension surface. Results from …
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Interfacial stress analysis and strengh prediction of plated rc beams
… understand the stress characteristics at this zone. This thesis reports a systematic investigation on the stress distribution at the interface between the concrete and the bonded plate and the prediction of the failure loads using the obtained stresses. A Finite Element Analysis (FEA) based on …
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Assessment of rock fracture initiation using acoustic emission
DSpace SAF Submission Ingestion Package generated from Vireo submission #14339 on 2019-11-26 at 14:04:18
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A scalable computational approach for modeling dynamic fracture of brittle solids in three dimensions
… proposed for modeling threedimensional dynamic fracture of brittle solids. The method is based on a combination of the discontinuous Galerkin (DG) formulation of the continuum elastodynamic problem with Cohesive Zone Models (CZM) of fracture. In the proposed framework, discontinuous displacement …
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