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Full-Text Articles in Engineering
Application Of The Variational Fracture Model To Hydraulic Fracturing In Poroelastic Media, Chukwudi Chukwudozie
Application Of The Variational Fracture Model To Hydraulic Fracturing In Poroelastic Media, Chukwudi Chukwudozie
LSU Doctoral Dissertations
Hydraulic fracturing has persisted through the use of simple numerical models to describe fracture geometry and propagation. Field tests provide evidence of interaction and merging of multiple fractures, complex fracture geometry and propagation paths. These complicated behaviors suggest that the simple models are incapable of serving as predictive tools for treatment designs. In addition, other commonly used models are designed without considering poroelastic effects even though a propagating hydraulic fracture induces deformation of the surrounding porous media. A rigorous hydraulic fracturing model capable of reproducing realistic fracture behaviors should couple rock deformation, fracture propagation and fluid flow in the both …
Image-Based Modeling Of Porous Media Using Fem And Lagrangian Particle Tracking, Paula Cysneiros Sanematsu
Image-Based Modeling Of Porous Media Using Fem And Lagrangian Particle Tracking, Paula Cysneiros Sanematsu
LSU Doctoral Dissertations
The study of fundamental flow and transport processes at the pore scale is essential to understanding how the mechanisms affect larger, field-scale, processes that occur in oil and gas recovery, groundwater flow, contaminant transport, and CO2 sequestration. Pore-scale imaging and modeling is one of the techniques used to investigate these fundamental mechanisms. Although extensive development of pore-scale imaging and modeling has occurred recently, some areas still need further advances. In this work, we address two areas: (1) imaging of bulk proppants and proppant-filled fractures under varying loading stress and flow simulation in these systems and (2) nanoparticle (NP) transport modeling …
Applications Of The Variational Approach To Fracture Mechanics, Ataollah Mesgarnejad
Applications Of The Variational Approach To Fracture Mechanics, Ataollah Mesgarnejad
LSU Doctoral Dissertations
In this study we present the variational approach to fracture mechanics as a versatile tool for the modeling of the fracture phenomenon in solids. Variational fracture mechanics restates the problem of initiation and propagation of cracks in solids as an energy minimization problem. The edifice of this energy minimization problem is such that unlike other methods (e.g. extended finite element method XFEM, cohesive-zone methods) the variational approach to fracture mechanics, diminishes the need for an a priori knowledge of the crack path or ad hoc assumptions in the form of path selection laws. We will show applications of the variational …
Finite Element Modeling Of Hot-Mix Asphalt Performance In The Laboratory, Hao Ying
Finite Element Modeling Of Hot-Mix Asphalt Performance In The Laboratory, Hao Ying
LSU Doctoral Dissertations
The theoretical investigation of Hot-Mix Asphalt (HMA) response in the dynamic modulus and the semi-circular bending (SCB) laboratory test procedures is necessary to understand the influence of various design parameters on the performance of the mix. In addition, laboratory tests such as the dynamic complex modulus assume that this material can be dealt with as a homogeneous material while overlooking the particulate nature of this composite. The ultimate goal of this study is to develop an advanced theoretical framework, based on three-dimensional (3D) finite element (FE) methods and digital image analysis techniques to describe the behavior of HMA in two …
Numerical Studies Of Flow In Porous Media Using An Unstructured Approach, Nathan Matthew Lane
Numerical Studies Of Flow In Porous Media Using An Unstructured Approach, Nathan Matthew Lane
LSU Doctoral Dissertations
Flow and transport in porous media is relevant to many areas of engineering and science including groundwater hydrology and the recovery of oil and gas. Porous materials are characterized by the unique shape and connectivity of the internal void structures which give rise to a large range in macroscopic transport properties. Historically an inability to accurately describe the internal pore-structure has prevented detailed study of the role of pore structure on transport. In recent decades however, the combination of high resolution imaging technologies with computational modeling has seen the development of fundamental pore-scale techniques for studying flow in porous media. …
Structural Integrity And Fatigue Crack Propagation Life Assessment Of Welded And Weld-Repaired Structures, Mohammad Shah Alam
Structural Integrity And Fatigue Crack Propagation Life Assessment Of Welded And Weld-Repaired Structures, Mohammad Shah Alam
LSU Doctoral Dissertations
Structural integrity is the science and technology of the margin between safety and disaster. Proper evaluation of the structural integrity and fatigue life of any structure (aircraft, ship, railways, bridges, gas and oil transmission pipelines, etc.) is important to ensure the public safety, environmental protection, and economical consideration. Catastrophic failure of any structure can be avoided if structural integrity is assessed and necessary precaution is taken appropriately. Structural integrity includes tasks in many areas, such as structural analysis, failure analysis, nondestructive testing, corrosion, fatigue and creep analysis, metallurgy and materials, fracture mechanics, fatigue life assessment, welding metallurgy, development of repairing …
Material Length Scales In Gradient-Dependent Plasticity/Damage And Size Effects: Theory And Computation, Rashid Kamel Abu Al-Rub
Material Length Scales In Gradient-Dependent Plasticity/Damage And Size Effects: Theory And Computation, Rashid Kamel Abu Al-Rub
LSU Doctoral Dissertations
Structural materials display a strong size-dependence when deformed non-uniformly into the inelastic range: smaller is stronger. This effect has important implications for an increasing number of applications in structural failure, electronics, functional coatings, composites, micro-electro-mechanical systems (MEMS), nanostructured materials, micro/nanometer fabrication technologies, etc. The mechanical behavior of these applications cannot be characterized by classical (local) continuum theories because they incorporate no ‘material length scales’ and consequently predict no size effects. On the other hand, it is still not possible to perform quantum and atomistic simulations on realistic time and structures. It is therefore necessary to develop a scale-dependent continuum theory …