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Showing 1 to 20 of 54 for “"fracture initiation"”.
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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 Study of Brittle Fracture Initiation in Mild Steel
Made available in DSpace on 2014-12-05T17:37:31Z (GMT). No. of bitstreams: 1 6206099.pdf: 3522776 bytes, checksum: 2a849eeb8ba2cbca74d7aaf57c4e6ddc (MD5) Previous issue date: 1962
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Fracture and hydraulic fracture initiation, propagation and coalescence in shale
… mechanism to initiate and propagate these fractures remains unclear. Moreover, it is unknown how the propagating fracture interacts with other fractures in the Earth. The objective of this research is to gain a fundamental understanding of the hydraulic fracturing process in shales through …
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A Model for Prediction of Fracture Initiation in Finite Element Analysis of Bolted Steel Connections
… paper studies the finite element prediction of fracture initiation in bolted structural steel connections using damage mechanics. A material failure envelope has previously been developed for aluminum extrusions using the IDS (instability, ductile, and shear) criterion. The IDS criterion is a …
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Fracture Initiation and Propagation in Low Porosity Crystalline Rocks: Implications for Excavation Damage Zone (EDZ) Mechanics
… damage to the surrounding rock mass through the initiation and propagation of fractures parallel to the excavation boundary due to disturbance to the in situ stress condition, as well as the excavation process quality. The induced fractures in depth away from the excavation surface can provide a …
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Effect of flaw shape and penetrating fluids on hydraulic fracture initiation and propagation in porous material (gypsum)
… fluids into the matrix of the rock in the initiation and propagation of hydraulic fractures. For this purpose, prismatic gypsum specimens were tested under external biaxial loads and hydraulic pressurized flaws. Four type of flaw shapes were tested: 5 mm circular flaw, single vertical flaw, …
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Identification of defect locations in forged products using the finite-element method
… with a number of previously published continuum fracture criteria to predict the fracture initiation sites. For certain of the successful criteria the level of deformation at fracture has also been predicted using critical values of fracture found experimentally from an axisymmetric tensile test. …
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Analytical and Experimental Investigation of Low-Cycle Fatigue Fracture in Structural Steel
… commonly described as Low-Cycle Fatigue (LCF). Fracture in steel structures caused by earthquakes can be associated with this mechanism. Mathematical expressions describing the material deterioration due to LCF are often referred to as LCF laws. The accurate determination of the safety of steel …
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Ductile fracture after complex loading histories : experimental investigation and constitutive modeling
… Different from previous works on the ductile fracture of sheet metal, this thesis research addresses the experimental and modeling issues related to the crack initiation in advanced high strength steels after loading direction reversal. The main outcome of the present work is a fracture …
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Ductile fracture modeling : theory, experimental investigation and numerical verification
The fracture initiation in ductile materials is governed by the damaging process along the plastic loading path. A new damage plasticity model for ductile fracture is proposed. Experimental results show that fracture initiation in uncracked ductile solids is sensitive to the hydrostatic pressure …
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Fracture path transitions in peels tests of medium carbon steel spot welds
Fracture path transition, from interfacial fracture to a pulled button, in peel tests of spot welds in SAE 1039 steel was evaluated to determine the controlling material properties. Welds were tested in the as welded condition and after tempering at various temperatures to develop a range of …
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Effective mechanical Properties of material models with random heterogeneities
… distribution of the elastic tensor and fracture strengths of material models with random heterogeneities. We start by investigating the effective elastic properties of one-, two-, and three-dimensional rectangular blocks whose Young's modulus varies spatially as a lognormal random field. …
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Axial behavior of drilled shafts in soft rock
… design equations for prediction of the yield and fracture initiation pressures and a framework for prediction of the tip pressure-displacement (q-z) behavior of rock sockets in soft rocks. A probabilistic Limit State Design (LSD) framework is adopted. Two limit states are evaluated, namely axial …
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Simulating fluid-solid interaction using smoothed particle hydrodynamics method
… The second application is the modeling of hydro-fracture initiation and propagation in rocks. A new general SPH numerical coupling method is developed to model the interaction between fluids and solids, which includes non-linear deformation and dynamic fracture initiation and propagation. A …
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A Numerical Study of the Influence of Void Growth on Ductile Fracture and Metal Extrusion
… discussed and estimates for the conditions for fracture initiation are given and compared with experimental results. The range of estimates now available from finite element calculations coincides quite well with the range of experimental data for materials containing inclusions which are only …
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Mode I Delamination Fracture Characterization of Polymeric Composites under Elevated Temperature
… (PMC). Accurate prediction of delamination initiation and propagation is important for the design and analysis of robust composite structures. Existing experimental methodologies that are based on linear elastic fracture mechanics are inadequate to characterize delamination fracture …
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Paint-bake effect on the plasticity and fracture of pre-strained aluminum 6451 sheets
… characterize the anisotropic plasticity and the fracture initiation in prestrained artificially-aged aluminum 6451 sheets. It is found that the combination of pre-straining up to 5% strain and heat treatment mainly changes the material's strain hardening behavior and the stress-state sensitivity …
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Rock fracture under static stress conditions
… an understanding of the mechanics of rock fracture, particularly under compressive stress conditions, is of fundamental importance. This thesis contains details of an investigation into the applicability of Griffith's brittle fracture theory, modified to account for the effects of crack …
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Modelagem de fratura dúctil em colisão de embarcações utilizando modelo de dano de Lemaitre modificado
… to simulate numerically the material’s ductile fracture, several failure criteria have been applied. With this perspective, thi3s article considers a new approach for the application of numerical analysis to ship collision and stranding, based on the Continuum Damage Mechanics (CDM), where new …
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Testing and modeling of the viscoplastic and fracture behavior of metallic foils used in lithium-ion batteries
… under impact loading, their plastic and fracture response is investigated in detail. Using a novel micro-tensile testing device with a piezoelectric actuator, dogbone specimens with a 1.25 mm wide and 5.7 mm long gage section are tested for three different in-plane material orientations …
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