Mechanics of Materials Commons^™

A Threshold Helium Leakage Detection Switch With Ultra Low Power Operation, Sulaiman Mohaidat, Fadi M. Alsaleem

Department of Mechanical and Materials Engineering: Faculty Publications

Detecting helium leakage is important in many applications, such as in dry cask nuclear waste storage systems. This work develops a helium detection system based on the relative permittivity (dielectric constant) difference between air and helium. This difference changes the status of an electrostatic microelectromechanical system (MEMS) switch. The switch is a capacitive-based device and requires a very negligible amount of power. Exciting the switch’s electrical resonance enhances the MEMS switch sensitivity to detect low helium concentration. This work simulates two different MEMS switch configurations: a cantilever-based MEMS modeled as a single-degreefreedom model and a clamped-clamped beam MEMS molded using …

A High-Strength Precipitation Hardened Cobalt-Free High-Entropy Alloy, Matthew Luebbe, Jiaqi Duan, Fan Zhang, Jonathan Poplawsky, Hans Pommeranke, Maalavan Arivu, Andrew Hoffman, Mario Buchely, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Recent studies on precipitation-hardened high-entropy alloys (HEAs) demonstrate their high strength and thermal stability, making them promising materials for high-temperature structural applications such as nuclear reactors. However, many existing HEAs contain cobalt (Co), which is unsuitable for nuclear applications because of the long-term activation issue of Co. Co is also expensive and considered a critical material for other applications. Therefore, it is desired to exclude Co from the composition. a Co-free (Fe0.3Ni0.3Mn0.3Cr0.1)88Ti4Al8 HEA was developed and studied in this work. in contrast to previous Co-free HEAs, this alloy is close to Equi atomic in its composition and promises a more …

Crystalline–Amorphous Nanostructures: Microstructure, Property And Modelling, Binqiang Wei, Lin Li, Lin Shao, Jian Wang

Department of Mechanical and Materials Engineering: Faculty Publications

Crystalline metals generally exhibit good deformability but low strength and poor irradiation tolerance. Amorphous materials in general display poor deformability but high strength and good irradiation tolerance. Interestingly, refining characteristic size can enhance the flow strength of crystalline metals and the deformability of amorphous materials. Thus, crystalline–amorphous nanostructures can exhibit an enhanced strength and an improved plastic flow stability. In addition, high-density interfaces can trap radiation-induced defects and accommodate free volume fluctuation. In this article, we review crystalline–amorphous nanocomposites with characteristic microstructures including nanolaminates, core–shell microstructures, and crystalline/amorphous-based dual-phase nanocomposites. The focus is put on synthesis of characteristic microstructures, deformation …

Plasmon Enhanced Quantum Properties Of Single Photon Emitters With Hybrid Hexagonal Boron Nitride Silver Nanocube Systems, Mohammadjavad Dowran, Andrew Butler, Suvechhya Lamichhane, Adam Erickson, Ufuk Kilic, Sy_Hwang Liou, Christos Argyropoulos, A. Laraoui

Department of Mechanical and Materials Engineering: Faculty Publications

Hexagonal boron nitride (hBN) has emerged as a promising ultrathin host of single photon emitters (SPEs) with favorable quantum properties at room temperature, making it a highly desirable element for integrated quantum photonic networks. One major challenge of using these SPEs in such applications is their low quantum efficiency. Recent studies have reported an improvement in quantum efficiency by up to two orders of magnitude when integrating an ensemble of emitters such as boron vacancy defects in multilayered hBN flakes embedded within metallic nanocavities. However, these experiments have not been extended to SPEs and are mainly focused on multiphoton effects. …

Physics-Based Crystal Plasticity Model For Predicting Microstructure Evolution And Dislocation Densities, Juyoung Jeong

LSU Doctoral Dissertations

This work presents three different studies investigating plastic deformation mechanisms in metals and alloys using crystal plasticity finite element (CPFE) modeling. The first study presents a new nonlocal crystal plasticity model for face-centered cubic single crystals under heterogeneous inelastic deformation. The model incorporates generalized constitutive relations that incorporate the thermally activated and drag mechanisms to cover different kinetics of viscoplastic flow in metals and describes the plastic flow and yielding of single-crystals using dislocation densities. The model is compared to micropillar compression experiments for copper single crystals and clarifies the complex microstructural evolution of dislocation densities in metals. The second …

Graphene Twistronics: Tuning The Absorption Spectrum And Achieving Metamaterial Properties, Ammar Armghan, Meshari Alsharari, Khaled Aliqab, Osamah Alsalman, Juveriya Parmar, Shobhit K. Patel

Department of Mechanical and Materials Engineering: Faculty Publications

Graphene twistronics using multilayer graphene is presented in such a way that it provides a metamaterial effect. This manuscript also analyzes the prediction of behavior using machine learning. The metamaterial effect is achieved by twisting the graphene layers. Graphene twistronics is a new concept for changing the electrical and optical properties of bilayer graphene by applying a small angle twist between the layers. The angle twists of 5^o, 10^o, and 15^o are analyzed for the proposed graphene twistronics design. Tuning in the absorption spectrum is achieved by applying small twists to the angles of the …

Heterogeneous Sensor Data Fusion For Multiscale, Shape Agnostic Flaw Detection In Laser Powder Bed Fusion Additive Manufacturing, Benjamin Bevans, Christopher Barrett, Thomas Spears, Aniruddha Gaikwad, Alex Riensche, Harold (Scott) Halliday, Prahalada Rao

Department of Mechanical and Materials Engineering: Faculty Publications

We developed and applied a novel approach for shape agnostic detection of multiscale flaws in laser powder bed fusion (LPBF) additive manufacturing using heterogenous in-situ sensor data. Flaws in LPBF range from porosity at the micro-scale (< 100 μm), layer related inconsistencies at the meso-scale (100 μm to 1 mm) and geometry-related flaws at the macroscale (> 1 mm). Existing data-driven models are primarily focused on detecting a specific type of LPBF flaw using signals from one type of sensor. Such approaches, which are trained on data from simple cuboid and cylindrical-shaped coupons, have met limited success when used for detecting multiscale flaws in complex LPBF parts. The objective of this work is to develop a heterogenous sensor data fusion …

Oh, My Darling Clementine: A Detailed History And Data Repository Of The Los Alamos Plutonium Fast Reactor, Hannah K. Patenaude, Franz J. Freibert

College of Sciences Graduate Student Research

The Los Alamos Plutonium Fast Reactor, Clementine, provided the first fast neutron spectrum using a metallic plutonium fuel system and liquid mercury coolant. Clementine is often mentioned in the history of fast, metal-fueled, or metal-cooled designs, with little public information regarding the specifications or timeline. This paper contains a synopsis of each report regarding the development, operation, experimental results, failures, and subsequent disassembly of Clementine to explore this unique reactor within the context of modern advanced reactor development.

Precious Plastics - Plastic Brick Machine Fabrication, Timothy Ukaobasi Kanu, Evi Paraskevi Troulis

Architectural Engineering

The goal of this research is to determine the structural parameters of the recycled plastic polypropylene when molded into bricks resembling CMU blocks. To accomplish this, three mechanisms had to be assembled: the shredder, the injector, and the 1x1 mold. A tensile and compression test were to be performed on the plastic brick, and the values would be used to compare the tensile and compressive strength of PP plastic bricks, as well as their modulus of elasticity and stress vs. Strain performance. These values would be analyzed to determine whether it would be feasible to build an entire plastic wall. …

Multifunctional Microgel-Based Cream Hydrogels For Postoperative Abdominal Adhesion Prevention, Bo Liu, Yunfan Kong, Olawale A. Alimi, Mitchell Kuss, Huiyin Tu, Wenfeng Hu, Abu Rafay, Kumar Vikas, Wen Shi, Megan Lerner, William L. Berry, Yulong Li, Mark A. Carlson, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

Postoperative abdominal adhesions are a common problem after surgery and can produce serious complications. Current anti-adhesive strategies focus mostly on physical barriers and are unsatisfactory and inefficient. In this study, we designed and synthesized advanced injectable cream-like hydrogels with multiple functionalities, including rapid gelation, self-healing, anti-oxidation, anti-inflammation, and anti-cellular adhesion. The multifunctional hydrogels were facilely formed by the conjugation reaction of epigallocatechin gallate (EGCG) and hyaluronic acid (HA)-based microgels and polyvinyl alcohol (PVA) based on the dynamic boronic ester bond. The physicochemical properties of the hydrogels including anti-oxidative and anti-inflammatory activities were systematically characterized. A mouse cecum-abdominal wall adhesion model …

Surface Characterization Of Particulate Dust Subjected To Dew-Induced Cementation, Mohamed Adawi

Student Theses and Dissertations

Accumulation of soils and other particulate matter on the front cover glass of solar photovoltaic (PV) modules results in transmission losses that detrimentally affect the power output of PV installations. Cementation reactions occur due to interactions between the dust and the glass surface in the presence of temperature, humidity, and ph. In this study, accelerated soiling and cementation tests on glass coupons were performed using a custom instrumented soiling chamber and several standardized soils (Arizona Test Dust, Aramco Test Dust, and China Test Dust) to assess soil adhesion and cementation behaviors. Water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS) …

Interfaces In Dynamic Brittle Fracture Of Pmma: A Peridynamic Analysis, Longzhen Wang, Javad Mehrmashhadi, Florin Bobaru

Department of Mechanical and Materials Engineering: Faculty Publications

Recent experiments in bonded PMMA layers have shown dramatic changes in dynamic crack growth characteristics depending on the interface location and toughness. In this paper we present a peridynamic (PD) analysis of this phenomenon and determine three elements that are essential in a model reproducing the observed fracture behavior: (1) softening near the crack tip to account for changes in PMMA due to heat-generation induced by the high strain rates reached around the crack tip in dynamic fracture; (2) independent extension (mode I) and shear (mode II) modes of fracture; (3) a two-parameter fracture model, which matches both strength and …

Effect Of Blank Moisture Content On Forming Behaviour And Mechanical Properties Of Paperboard Tray Packages, Arvo Niini, Lena Berthold, Tobias Müller, Panu Tanninen, Jens-Peter Majschak, Juha Varis, Ville Leminen

Journal of Applied Packaging Research

Tray blanks were moisturised to study the effect of different blank moisture content levels on forming behaviour and mechanical properties of paperboard tray packages. The blank moisturisation was done by spraying water to the blanks before their three-dimensional (3D) forming. The trays were 3D formed by press forming or deep drawing. Visual quality and punch force values were used as indicators to evaluate the forming behaviour of the trays. The mechanical properties of the trays were investigated with compression, torsion, and storing tests. A high blank moisture content reduced the punch force, and the elevated blank moisture was connected to …

Freespan Analysis For Subsea Pipeline Integrity Management Strategy, Nurul Hadi, Muhammad Helmi, Edo Cathaputra, Dedi Priadi, Donanta Dhaneswara

Journal of Materials Exploration and Findings

Abstract. Over a rough seabed or on seabed subject to scour, freespans can occur when contact between a subsea pipeline and the seabed is lost over an acceptable distance. When this exceeds the allowable freespan length, design stresses can be exceeded, and a vortex induced vibration (VIV) response can be initiated, resulting in the risk of fatigue failure. If this is not predicted and controlled properly, it will affect pipeline integrity, leading to expensive rectification and intervention work. Freespan analysis consisted primarily of a screening check in which the as-found freespans from Remotely Operated Vehicle (ROV) or multibeam Side …

Locally Resonant Metasurface For Low-Frequency Transmissive Underwater Acoustic Waves, Zhong Chen, Shenghong Guan, Qiang Xie, Zheng Li, Zhongmei Gao, Mehrdad Negahban

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction: Acoustic metasurfaces for underwater wave manipulation have great potential use, but the strong solid-fluid interaction caused by impedance closeness between the structure and water brings design difficulty, especially in the low-frequency range.

Methods: Here a locally resonant metasurface for transmissive underwater acoustic waves is proposed using finite element method for which each metasurface unit consists of one channel and three subunits. Each subunit has one plate and two rubber spacers to form a resonator. By changing the height ratio of the plate over the subunit, arbitrary phase shifts within the full 2π coverage can be obtained at …

An Efficient And Low-Cost Method To Create High-Density Nitrogen-Vacancy Centers In Cvd Diamond For Sensing Applications., Prem Bahadur Karki, Rupak Timalsina, Mohammadjavad Dowran, Ayodimeji E. Aregbesola, Abdelghani Laraoui, Kapildeb Ambal

Department of Mechanical and Materials Engineering: Faculty Publications

The negatively charged Nitrogen-Vacancy (NV^-) center in diamond is one of the most versatile and robust quantum sensors suitable for quantum technologies, including magnetic field and temperature sensors. For precision sensing applications, densely packed NV^- centers within a small volume are preferable due to benefiting from 1/√𝑁 sensitivity enhancement (N is the number of sensing NV centers) and efficient excitation of NV centers. However, methods for quickly and efficiently forming high concentrations of NV^- centers are in development stage. We report an efficient, low-cost method for creating high-density NV^- centers production from a relatively …

Correction: Nanoscale Imaging Of Antiferromagnetic Domains In Epitaxial Films Of Cr2o3 Via Scanning Diamond Magnetic Probe Microscopy, Adam Erickson, Syed Qamar Abbas Shah, Ather Mahmood, Ilja Fescenko, Rupak Timalsina, Christian H. Binek, Abdelghani Laraoui

Department of Mechanical and Materials Engineering: Faculty Publications

Correction for ‘Nanoscale imaging of antiferromagnetic domains in epitaxial films of Cr2O3 via scanning diamond magnetic probe microscopy’ by Adam Erickson et al., RSC Adv., 2023, 13, 178–185, https:// doi.org/10.1039/D2RA06440E

Traversing With Quantitative Fidelity Through The Glass Transition Of Amorphous Polymers: Modeling The Thermodynamic Dilatational Flow Of Polycarbonate, Mehrdad Negahban, Wenlong Li, Jean-Marc Saiter, Laurent Delbreilh, Kyle Strabala, Zheng Li

Department of Mechanical and Materials Engineering: Faculty Publications

We follow the assumption that the dilatational response of glassy polymers can be characterized by a back-stress type analog that includes a thermal expansion for each elastic component, and with a viscosity that is dependent on the expansion of the elastic back stress component. To this, we add the assumption of an unloaded equilibrium temperature that correlates to the past processing through the viscous flow. After setting this in a thermodynamically consistent structure, the elastic, elastic backstress, thermal expansion, back-stress thermal expansion, heat capacity and viscous damping are evaluated using existing experiments for the response of polycarbonate over the glassy …

Peridynamic Simulation Of Elastic Wave Propagation By Applying The Boundary Conditions With The Surface Node Method, Francesco Scabbia, Mirco Zaccariotto, Ugo Galvanetto, Florin Bobaru

Department of Mechanical and Materials Engineering: Faculty Publications

Peridynamics is a novel nonlocal theory able to deal with discontinuities, such as crack initiation and propagation. Near the boundaries, due to the incomplete nonlocal region, the peridynamic surface effect is present, and its reduction relies on using a very small horizon, which ends up being expensive computationally. Furthermore, the imposition of nonlocal boundary conditions in a local way is often required. The surface node method has been proposed to solve both the aforementioned issues, providing enhanced accuracy near the boundaries of the body. This method has been verified in the cases of quasi-static elastic problems and diffusion problems evolving …

Elastic Properties Of The Non-Mixing Copper Donor Assisted Material In Friction Stir Welding Of Aluminum Alloys Using Nanoindentation, M. Ojha, A. H. Al-Allaq, Y. S. Mohammed, S. N. Bhukya, Z. Wu, A. A. Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

Friction stir welding of high-strength materials such as steels is the impeded by the lack of the vast heat input needed to start the process. Contact friction is considered the most dominant source of heat generation for FSW steels which tends to cause severe wear conditions of the tool hear. To relieve the extreme wear conditions that occur on the tool heads because of FSW steels, we introduce the non-mixing Cu donor stir material to friction stir welding of aluminum alloys. The elastic properties of the Cu donor assisted friction stir welded aluminum alloys are measured using nanoindentation. The hardness …