Mechanics of Materials Commons^™

Functional Verification Of Additively Manufactured Metallopolymer Structures For Structural Electronics Design, Nathan D. Singhal

Honors Undergraduate Theses

As an attempt to improve the overall cost-effectiveness and ease of structural electronics manufacturing, this study characterizes the mechanical and electrical responses of structures which are fabricated from a novel metallopolymer composite material by fused deposition modeling as they are subjected to quasi-static, uniaxial mechanical tension. Baseline values of tensile properties and electrical resistivity were first obtained via ASTM D638-22 standard testing procedures and linear sweep voltammetry (LSV), respectively. A hybrid procedure to measure in-situ mechanically dependent electrical behavior was subsequently developed and implemented. The mechanical and electromechanical testing was followed by the derivation of stochastic values for several mechanical …

Experimental Characterization And Quantification Of Deformation Behavior In A Porous Carbon Fiber Network, Robert N Quammen

Theses and Dissertations--Chemical and Materials Engineering

Due to their wide range of attractive functional properties (such as low thermal conductivity and low density) porous materials are utilized in a variety of applications. In order to characterize these properties and others, the intrinsically heterogeneous microstructures of these materials need to be taken into account. These microstructures result in interactions across multiple length scales spanning several orders of magnitude. This makes the creation of robust computational models and straight-forward predictions of mechanical properties difficult for porous materials. With this in mind, this dissertation aims to provide experimental mechanical and deformation information spanning the length scales of interest for …

Impact Of Quenching Intensity Conditions On Using A Finite Element Model To Investigate The Microstructure And Hardenability Of Low-Alloy Steel, J. S. Alabi, E. Heidari, M. F. Buchely, K. Chandrashekhara, S. N. Lekakh, R. J. O'Malley, V. Athavale, A. Kumar

Materials Science and Engineering Faculty Research & Creative Works

Quenching is one of the primary processes to improve mechanical properties in steels, particularly hardness. Quenching is well established for different geometries of individually treated steel components; while in-steam quenching of large diameter continuously cast steel bar has several specific features which are difficult and costly to experimentally optimize. the end-quench Jominy test has been used extensively to study the hardenability of different steel grades. Different numerical, analytical, and empirical models have been developed to simulate the Jominy process and to understand quenching of steels. However, it is not straight forward to translate experimental data from Jominy test on instream …

Impact Of Quenching Intensity Conditions On Using A Finite Element Model To Investigate The Microstructure And Hardenability Of Low-Alloy Steel, J. S. Alabi, E. Heidari, M. F. Buchely, K. Chandrashekhara, S. N. Lekakh, R. J. O'Malley, V. Athavale, A. Kumar

Materials Science and Engineering Faculty Research & Creative Works

Quenching is one of the primary processes to improve mechanical properties in steels, particularly hardness. Quenching is well established for different geometries of individually treated steel components; while in-steam quenching of large diameter continuously cast steel bar has several specific features which are difficult and costly to experimentally optimize. The end-quench Jominy test has been used extensively to study the hardenability of different steel grades. Different numerical, analytical, and empirical models have been developed to simulate the Jominy process and to understand quenching of steels. However, it is not straight forward to translate experimental data from Jominy test on instream …

Inherently Porous Metal Structures With Sufficient Mechanical Properties Through Direct Writing Of Bio-Based Inks, Havva Eda Aysal

Graduate Theses, Dissertations, and Problem Reports (ETD)

There is currently a burgeoning interest in developing 3D printed metal structures with inherent porosity and sufficient mechanical properties for mass customization in the biomedical field. Current approaches for 3D printing of biocompatible metals rely on powder-bed fusion methods which are energy intensive and utilize large amounts of metal powder that is challenging to recycle. In addition, such methods aim on producing dense parts and porosity generation, within the printed part, is challenging due to the complex physics of the melting pool. Here, a relatively new and promising approach is undertaken to study the 3D printing of inherently porous structures …

Modification Of Gas Atomized Metal Powders Through Mechanical Chemical Bonding Technique, Philip Thomas Mallory

Graduate Theses, Dissertations, and Problem Reports (ETD)

Additive Manufacturing (AM) has become popular for commercial applications where high-performance parts can now be created, tested, and modified more efficiently thus expediting the design process. Because of its relatively easy access today a lot of research and improvements are coming out yearly for improved AM machines and the material used. At WVU, a new way of modifying as-receive commercial gas-atomized metal powders used in AM has been developed using Mechanical Chemical Bonding (MCB) methodology which uses high rotational blades to create an environment where it increases the particle-on-particle interaction. During this high energetic process all irregular shaped particles, with …

Multi-Mode Regulation Of The Drying Process Of Industrial Gas, Isamidin Xakimovich Sidikov Pr, Nashvandova Gulruxsor Murot Qizi Phd

Technical science and innovation

Currently, much attention is paid to the issue of energy efficiency of gas processing enterprises. The continuous growth of world prices for energy resources requires constant improvement of the management system, providing the most optimal conditions for the flow of technological processes. A conceptual model of the heat-mass transfer process occurring in the absorber as an object of research has been developed, which characterizes the relationship of the variables involved in the drying process of natural gas, control, measurable and immeasurable, as well as controlled parameters have been selected, which are used to develop and study a mathematical model of …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

Exploring Regular And Turbulent Flow States In Active Nematic Channel Flow Via Exact Coherent Structures And Their Invariant Manifolds, Caleb G. Wagner, Rumayel H. Pallock, Jae Sung Park, Michael M. Norton, Piyush Grover

Department of Mechanical and Materials Engineering: Faculty Publications

This work is a unified study of stable and unstable steady states of 2D active nematic channel flow using the framework of Exact Coherent Structures (ECSs). ECSs are stationary, periodic, quasiperiodic, or traveling wave solutions of the governing equations that, together with their invariant manifolds, organize the dynamics of nonlinear continuum systems. We extend our earlier work on ECSs in the preturbulent regime by performing a comprehensive study of stable and unstable ECSs for a wide range of activity values spanning the preturbulent and turbulent regimes. In the weakly turbulent regime, we compute more than 200 unstable ECSs that coexist …

Structural Performance And Resiliency Of Reinforced Concrete Bridge Pier Columns, Multi-Column Piers, And Bridge Systems Subjected To Multiple Hazards – Fire, Collision, And Air Blast, Qusai Abdulkarim Alomari

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Given their close proximity to traffic and improper employment of protective systems, bridges and bridge piers are vulnerable to multi-hazard events triggered by vehicle collisions coupled with correlated and cascading events, such as explosions and fires. Despite recent catastrophic incidents that have highlighted the profound consequences of these extreme demands, including substantial damage, adverse economic impact, and loss of life, there has been a notable lack of research investigating the performance of bridges and bridge structural components under the aforementioned multi-hazards. Furthermore, current bridge design codes do not address these events assuming that, after these destructive events, replacement of the …

Effect Of Multiple Machine Configurations And Wall Thickness On Microstructure And Microhardness Of Laser Powder Bed Fusion (L-Pbf) Additively Manufactured Heat-Treated Inconel 718 Products, Anannya Doris

Open Access Theses & Dissertations

This research examined thin section prototypes having seven nominal thicknesses ranging from 0.1 to 2.0 mm, composing a series of geometric feature build plates manufactured by multiple laser powder bed fusion (L-PBF) machine configurations. The build plates and thin section feature prototypes underwent a full heat treatment cycle per established standards: anneal at 1066°C, SR+HIP at 1163°C, and fully treat-treated by combining SR+HIP+solution treatment at 1066°C and double aging treatment at 760°C and 680°C, respectively. The fully heat-treated (FHT) Inconel 718 wall specimens were sectioned from 16 distinct geometric feature build plates constructed on 15 different L-PBF machines. The thin …

Upcyclying Of Polyethylene Terephtalate By Addition Of Thermoplastic Elastomer, Diego Francisco Bermudez

Open Access Theses & Dissertations

Continual overconsumption of single-use plastics has generated challenges of solid waste management across the United States. Common plastic waste management solutions, such as landfill, have caused the migration of contaminants into the environment consequently affecting not only the health of wildlife, but also that of human beings. Alternative strategies for the handling of single-use plastic such as polyethylene terephthalate (PET), used in the food packaging industry, can ultimately help mitigate the noxious consequences of single-use plastics affecting entire ecosystems. This study demonstrates a potential avenue of materials upcycling by studying the effects of coupling PET with the thermoplastic elastomer styrene-ethylene-butylene-styrene …

Niobate Nanosheet Catalysts For Cationic Dye Intercalation And Solar-Driven Water Photolysis, Cassandra Idona Monárrez-Grendahl

Open Access Theses & Dissertations

With the goal of creating efficient visible light photocatalysts for water photolysis, in this work we are exploring the synthesis of new porous oxide materials derived from potassium triniobate (KNb3O8) and titanium niobium oxide (KTiNbO5), which are layered wide band gap semiconductors. Generating hydrogen via direct water photolysis holds promise as a way to lower the cost of hydrogen gas production so it can be used as a renewable and clean alternative fuel. My group has demonstrated that layered semiconductor materials have the potential to enable the synthesis of new types of photocatalyst composites with customizable characteristics. In this work, …

Ultra Wide Band Gap Oxides For Advanced Optoelectronics And Supercapacitor Applications: A Case Study Of Intrinsic And Doped Germanium Dioxide, Paul Gaurav Nalam

Open Access Theses & Dissertations

Germanium dioxide (GeO2) is a metal oxide semiconductor with multiple polymorphs that has recently garnered a significant amount of scientific attention owing to its novel ultra-wide band gap and pseudo-capacitive properties, which can potentially transcend current power electronic, optoelectronic, and supercapacitor technologies. However, due to the difficulty in the synthesis of stable crystalline phases of individual polymorphs of GeO2 thin films, this material system demands complex and resource-intensive deposition techniques to synthesize. An attempt was made to develop cost-effective and scalable deposition techniques to stabilize specific crystalline phases of GeO2 thin films. These phases were further structurally fine-tuned to state …

Ultrasonic Non-Destructive Evaluation Of Additively Manufactured Polymer-Ceramic Composites, Christian Alexander Ruiz

Open Access Theses & Dissertations

Digital light processing (DLP) is an attractive additive manufacturing technique due to its ability to create ceramic parts with complex geometries. DLP uses ultraviolet light to polymerize a slurry comprised of ceramic powder and photosensitive resin in layers to create solid parts. Printing parameters such as light intensity and exposure time are critical when producing these parts. Improper parameters can lead to over or under-curing, adversely impacting print quality and strength. Samples were printed at varying layer exposure times and then tested using ultrasonics to determine the degree of conversion. Additionally, ultrasonics were used as a non-destructive technique to obtain …

Development Of A 3d Printed Conductive Biopolymer For Cardiac Tissue Engineering, Britanny Lizeth Stark

Open Access Theses & Dissertations

Cardiovascular disease (CVD) is the leading cause of death in the US, with approximately 859,000 deaths each year. The major contributor to CVD is Acute Myocardial Infarction (AMI), which causes the death of approximately 25% of the cardiomyocytes present in the left ventricle of the heart. After AMI, the adult human heart has a very limited regenerative capacity. Moreover, the electrical propagation of the myocardium is severely disrupted, making the heart more susceptible to failure and patient death. However, current pharmacological treatments do not address the loss of cardiomyocytes and the disruption of electrical propagation in the heart. Tissue engineering …

Characterization Of Fcc Al-Cu-Ni-Mn-Ag High Entropy Alloy, Gina Zavala Alvarado

Open Access Theses & Dissertations

The effect of Ag on the microstructure developed in Al-Cu-Ni-Mn alloy has been determined. The modified Al-Cu-Ni-Mn alloy by Ag addition shows the presence of three microconstituents consisting of phases rich in (1) Cu, (2) Ni, and (3) Ag. The foregoing alloys heated for 24 hours from 600 to 1000 °C show excellent oxidation resistance. Oxide formation and microstructural changes of the alloy have been characterized by elemental mapping and X-ray diffraction (XRD). Results show that the elements of Al and Mn preferentially oxidize while Cu and Ni provide oxidation resistance to the alloy. Hardness was taken on the alloy …

Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams

All Dissertations

While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …

Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav

Theses and Dissertations

Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …

What Does It Mean To Be “Prepared For Work”? Perceptions Of New Engineers, Jessica R. Deters, Marie C. Paretti, Logan A. Perry, Robin Ott

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Engineering education seeks to prepare students for engineering practice, but the concept of preparedness is often ill-defined. Moreover, findings from studies of different populations or in different contexts vary regarding how well new graduates are prepared. These variations, coupled with the lack of clarity, suggest the need to better understand what it means to be prepared for engineering work.

Purpose: This study contributes to research on workplace preparation by exploring how new graduates describe being prepared for engineering work.

Method: Applying secondary analysis to data from the multi-institution Capstone To Work (C2W) project, we used thematic …