Structural Materials Commons^™

3d Experimental Studies Of Temperature And Crystallographic Effects On Creep And Strength In Rock Salt, Amirsalar Moslehy

Doctoral Dissertations

Salt domes utilization as storage reservoirs in the energy sector has led to extensive studies on rock salt’s mechanical and geothermal behavior. These important facilities’ safety and serviceability rely on understanding rock salt’s compressive strength and creep behavior under various loading directions, water contents, in-situ stresses, and temperatures. Despite numerous studies on rock salt’s mechanical behavior in the literature, there are still many unanswered questions about rock salt’s behavior. This dissertation was aimed at utilizing state-of-the-art experimental techniques such as 3D synchrotron micro-computed tomography (SMT) and 3D x-ray diffraction (3DXRD) along with hundreds of compression and creep experiments to enhance …

Modular Composite Sandwich Structures For Thermal And Structural Retrofitting Of Existing Buildings, Marc Al Ghazal

Masters Theses

Around 40% of global energy consumption and 30% of worldwide carbon dioxide (CO2) emissions are attributed to buildings. Most of this consumption is dedicated to ensuring thermal comfort. The goal of this research was to develop and field validate retrofit solutions to improve the energy efficiency of buildings. Exterior cladding panels were designed and tested to ensure adequate thermal and structural performance. Sandwich panels (glass fibers reinforced polymer (GFRP) skins and polymeric foam cores) were fabricated using the vacuum assisted resin transfer molding (VARTM) process. Extruded polystyrene (XPS) and polyurethane (PU) foams were compared as core materials through a series …

A Study On Early Age Properties Of Concrete For Precast And 3d Printing, Debalina Ghosh

Doctoral Dissertations

Concrete is the second-most consumed material, leading the global Portland cement production of 4.1 billion tons in 2020 and 5-8% of global Carbon dioxide (CO₂) emission annually. As with any other material and practice, the construction industry is also ever-changing to meet market demand, evolving technology, and resource limitation. In the case of concrete construction, one of the main concerns is the lack of automation. In the last few decades, some new construction methods have risen to address this concern. Some of these economic and successful practices are precast construction, self-compacting concrete (SCC), and 3D printing of concrete(3DPC). …

Microscopic And Image Processing Characterization Of Aggregates To Predict Asr Expansion Potential Of Concrete, Ammar Elfatih Abdelssamd Elhassan

Doctoral Dissertations

Preventing ASR occurrence in new concrete structures requires reliable and quick methods to identify reactive aggregates and to evaluate proper mitigation alternatives. The current accelerated mortar-bar expansion tests (ASTM C 1260 or ASTM C1567) and the concrete prism expansion test (ASTM C 1293) have been reported to have several limitations. Assessment of the extend of ASR damage in existing affected structures requires more understanding on how ASR expansion and damage develop in field conditions such as under confinements and under relatively slow rate of ASR reaction.

The significance of ASR expansion rate and bi-axial restrain on concrete degradation has been …

Neutron Diffraction Study Of Engineering Materials Subjected To Complex Loadings, Jeffrey R. Bunn

Doctoral Dissertations

No studies using diffraction have specifically aimed to study the (hkl) specific shear strain of lattice planes to the application of pure shear due to applied torsion. Also no measures of strain resultant from combined loads of tension and shear stress applied simultaneously have been performed. Current techniques simply measure the planar response to axial stress and cannot provide shear strains directly. Shear moduli are not necessarily related through traditional continuum mechanics to planar Youngs’ moduli (E_hkl) from these axial experiments for all materials. This is of significance as most engineering components fail under the …

An Automated Finite Element Analysis Framework For The Probabilistic Evaluation Of Composite Lamina Properties, Jonathan Phillips Weigand

Masters Theses

This thesis outlines the development of computational modeling tools used to predict the elastic properties of composite lamina from representative volume elements (RVE) using numerical methods. The homogenization approach involves the use of Gauss’s Theorem to simply the average volumetric strain integral into a surface integral containing which is defined by surface displacements and their direction. Simulations of RVEs under specific loading conditions (longitudinal tension or shear and transverse tension or shear) are then performed in the software package ABAQUS to obtain the surface displacements. It was found that obtaining quality meshes and applying periodic boundary conditions for each RVE …

Investigating Properties Of Pavement Materials Utilizing Loaded Wheel Tester (Lwt), Hao Wu

Doctoral Dissertations

Loaded wheel tester (LWT) is a common testing equipment usually used to test the permanent deformation and moisture susceptibility of asphalt mixtures by applying moving wheel loads on asphalt mixture specimens. It has been widely used in the United States since 1980s and practically each Department of Transportation or highway agency owns one or more LWT(s). Compared to other testing methods for pavement materials, LWT features movable wheel loads that allow more realistic situations existing on the actual pavement to be simulated in the laboratory. Due to its potential of creating a condition of repetitive loading, the concept of using …