Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 56 for “"ductile fracture"”.
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Elastic-Damaging Plasticity Model for Ductile Fracture
… of a simple material model that can characterize ductile fracture in ferritic steels and that can be used in practical engineering problems. Ductile fracture occurs by a sequential process of nucleation, growth and coalescence of microvoids or microcracks. However, the model uses a continuum …
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Ductile fracture by the growth of pores
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1961.
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A study of plane strain ductile fracture.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1971.
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Ductile fracture and structural integrity of pipelines & risers
… environment. The structural integrity and fracture control of pipes, which are major components for the exploration, production and transportation of fossil fuels have been the subject of extensive analysis in the past decade using classical fracture mechanics approaches, especially for the …
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A study of anisotropic and viscoelastic ductile fracture
The problem of ductile fracture in anisotropic and viscoelastic solids is an important engineering problem. In this paper the Dugdale model is assumed, that is, the yielded zone is replaced by a constant yield stress. Solutions are presented for anisotropic static, orthotropic dynamic and …
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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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The effects of microstructure and nanostructure upon dynamic ductile fracture
Dynamic fracture is an important process in the behaviour of materials. However, the effects of material microstructure on dynamic fracture processes are not well understood. This thesis investigates the role of material microstructure and nanostructure in dynamic ductile fracture, such that the …
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Hardening Cohesive/Overlapping Zone Model and Fractal Approach to Ductile Fracture
Most of fracture parameters (K, G, J-integral, COD) break down, especially for ductile materials and large crack extensions. In addition, even at small scale yielding, K, G, J- integral and COD are limitedly used to distinguish the onset of unstable fracture, without any concern regarding the …
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Simulation of Ductile Fracture in Pipeline Steels Under Varying Constraint Conditions
… boundary layer (MBL), and (2) to simulate ductile crack propagation in pipeline steels using drop weight tear test (DWTT) and comparing these FE simulations with experimental results. The calibration of various CZM was done using different traction-separation laws. Mainly, three models …
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Ductile fracture after complex loading histories : experimental investigation and constitutive modeling
… paths. 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 …
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Experimental study of ductile fracture of tubes under combined tension/torsion
… values in the plastic region. The specimen fractured at a rotation of 430 with a plastic strain of 1.013. This was 2.4 times higher than in the tension simulation, where the specimen failed at a strain of 0.427.
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Anisotropic ductile fracture of metal sheets : experimental investigation and constitutive modeling
… of large strain plastic deformation and ductile fracture under multi-axial loading is highly relevant to various industrial applications such as metal forming, impact failure of structures, etc. In this thesis, a comprehensive study of the plasticity and ductile fracture of anisotropic …
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The Effect of Pre-strain and Strain Path Changes on Ductile Fracture
… from those deformed in a given direction to fracture. The work presented here employed laser drilled model materials to better understand the effect of pre-strains and strain path changes on void growth and linkage leading to fracture is studied. The experimental results show that increasing …
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Ductile fracture at intermediate stress triaxialities : experimental investigations and micro-mechanical modeling
Accurate predictions of the onset of ductile fracture play an increasingly important role in the design of lightweight sheet metal structures. With the development of virtual prototyping practices, most transportation vehicles are now computer-engineered in great detail before launching their mass …
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Finite element assisted prediction of ductile fracture in sheet bulging of magnesium alloys
… introduce a range of failure that will predict fracture over a range of draw depths rather than a single depth. It is difficult to make the leap from a process that is unpredictable to pinpointing the exact point of failure. It is more logical to firstly determine a range of formability where …
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Phase-field modeling of fracture: regularization length insensitivity and mixed mode ductile fracture
… time, and occasional impossibility of performing fracture experiments, computational approaches have become instrumental to understand and assess fracture and failure processes in materials and optimize the design of structures. The development of quantitative computational models for predicting …
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Mechanisms of Ductile Fracture: Void Growth by Dislocation -Loop Emission and Hydrogen-Assisted Crack Propagation
… crack 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 …
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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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Numerical Analysis of the Effects of Void Growth and Crack Tip Opening on Ductile Fracture
The ductile rupture of metal alloys depends on the presence of small second phase particles which nucleate microscopic voids. Plastic flow in the metal allows the voids to grow and link up to create larger flaws such as cracks. In previous research, the basic mechanics of ductile fracture has been …
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Effects of Ti, Zr, and Al nitrides on ductile fracture in thin plates of hardened O.3C steels, The
Includes bibliographical references.
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