Engineering Science and Materials Commons^™

Method Of Making Hinged Self-Referencing Fabry–Pérot Cavity Sensors [U.S. Patent Us11287575b2], Jeremiah C. Williams, Hengky Chandrahalim

Faculty Publications

A method is provided for fabricating a passive optical sensor on a tip of an optical fiber. The method includes perpendicularly cleaving a tip of an optical fiber and mounting the tip of the optical fiber in a specimen holder of a photosensitive polymer three-dimensional micromachining machine. The method includes forming a three-dimensional microscopic optical structure within the photosensitive polymer that comprises a two cavity Fabry-Perot Interferometer (FPI) having a hinged optical layer that is pivotally coupled to a suspended structure. The method includes removing an uncured portion of the photosensitive polymer using a solvent. The method includes depositing a …

Closed-Loop Control Of Meltpool Temperature In Directed Energy Deposition, Ziyad M. Smoqi, Ben Bevans, Aniruddha Gaikwad, James Craig, Alan Abul-Haj, Brent Roeder, Bill Macy, Jeffrey E. Shield, Prahalada K. Rao

Mechanical & Materials Engineering Faculty Publications

The objective of this work is to mitigate flaw formation in powder and laser-based directed energy deposition (DED) additive manufacturing process through close-loop control of the meltpool temperature. In this work, the meltpool temperature was controlled by modulating the laser power based on feedback signals from a coaxial two-wavelength imaging pyrometer. The utility of closed-loop control in DED is demonstrated in the context of practically inspired trapezoid-shaped stainlesssteel parts (SS 316L). We demonstrate that parts built under closed-loop control have reduced variation in porosity and uniform microstructure compared to parts built under open-loop conditions. For example, post-process characterization showed that …

Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz

Faculty Publications

Structural optimization is a methodology used to generate novel structures within a design space by finding a maximum or minimum point within a set of constraints. Topology optimization, as a subset of structural optimization, is often used as a means for light-weighting a structure while maintaining mechanical performance. This article presents the mathematical basis for topology optimization, focused primarily on the Bi-directional Evolutionary Structural Optimization (BESO) and Solid Isotropic Material with Penalization (SIMP) methodologies, then applying the SIMP methodology to a case study of additively manufactured lattice cells. Three lattice designs were used: the Diamond, I-WP, and Primitive cells. These …

Design And Testing Of A Composite Compressor Rotor, Mauro Noel V. De Leon

Theses and Dissertations

Additive manufacturing (AM) and molding are manufacturing methods known for building representations or replicas of conceptualized engine components, but was considered impractical for manufacturing operating engine components. More recent technology has rendered composite materials (combining high-temperature polymers and fiber reinforcement) capable of withstanding the temperature and structural requirements to compete with conventional turbomachinery metals. This study explores the application of several high-temperature polymers (ULTEM 9085, Onyx-Carbon fiber, and Epoxy-Carbon fiber) and their survivability in the operating conditions of a P400 Engine compressor. The tests conducted for this study determined their viability as compressor materials. This study required conducting tensile specimen …

Thermal Relaxation Of Shot Peen Induced Residual Stresses In A Nickel-Base Superalloy, Bryce E. Van Velson

Theses and Dissertations

Shot peening induces compressive residual stresses in components that positively influence fatigue life. Thermal and mechanical loading causes those residual stresses to relax. The hole drilling method and xray diffraction is used to measure the thermal relaxation of residual stresses in the nickel-base superalloy ME3.

A Study On The Early Stages Of Degradation Of Multi-Component Alloy Surfaces In Extreme Environments Using The Multi-Cell Monte Carlo Method, Tyler D. Dolezal

Theses and Dissertations

A computational toolset is presented and used in two examples that examined the interactions between structural materials and their extreme environments. A multi-cell Monte Carlo algorithm was developed to generate thermodynamically realistic solid-state alloy systems. These structures served as the foundation upon which surface slab models were generated. The tedious procedure of generating surface slab models from bulk structures was automated. The tools were used to study the high temperature surface corrosion resistance of a high-entropy alloy, Al₁₀Nb₁₅Ta₅Ti₃₀Zr₄₀, and a nickel-based alloy, Ni₇₀Nb₁₀W₂₀, under …

A Computational Fluid Dynamics-Based Surrogate Wind Turbine Blade Aerodynamic Model For Hybrid Simulation, Eric Lalonde

Electronic Thesis and Dissertation Repository

Hybrid simulation (HS) is a promising technique for studying wind turbines due to the presence of scaling errors in wind tunnel testing. However, HS of wind-loaded structures is limited by the current practice of using lower-accuracy, "pre-calculated" aerodynamic loads, which uncouple the aerodynamic loading from the structural response. This thesis presents six stand-alone studies that collectively build towards a novel HS framework that employs a computational fluid dynamics (CFD) based surrogate model to generate higher-accuracy aerodynamic loads within the HS loop. An experimentally-validated residential wind turbine model equipped with an external damping system was used to illustrate the proposed framework. …

A Simulation Model To Determine The Supply Chain Optimum Order Quality, Ahmed Mohamed Saleh

Archived Theses and Dissertations

No abstract provided.

A Materials Study Of Topological Insulators And Two-Dimensional Ferromagnets, Sarah Friedensen

Publicly Accessible Penn Dissertations

Topological insulators and two-dimensional ferromagnetic materials are novel phases with wideranging applications including quantum computing, spintronics, and other advanced electronic devices with the potential for ultrathin and ultralow-power wearables. TEM, AFM, EDS, Ramanspectroscopy, and low-temperature transport measurement are used to characterize an unusual superconducting alloy formed between palladium and bismuth selenide under low-temperature annealing. TEM, AFM, and EDS are used to perform a materials study of metallic nickel and niobium annealed with Bi2Se3 under similar conditions, with the conclusion that Ni reacts to form a diffuse layer within Bi2Se3 flakes that travels along edges and line defects, and Nb does …

Polymer Dynamics In Disordered Nanoparticle Packings: Effect Of Confinement, Interfaces, And Humidity, R Bharath Venkatesh

Publicly Accessible Penn Dissertations

Infiltration of polymers into disordered nanoparticle packings has shown to be a powerful method of fabricating highly loaded nanocomposites with superb mechanical properties. Polymer-infiltrated nanoparticle packings provide a unique platform to study the dynamics of macromolecules under extreme nanoconfinement. The degree of confinement can be tuned by appropriate choice of particle size and polymer molecular weight. The presence of large interfacial area between the polymer and the particle, high degree of nanoconfinement, and environmental triggers like atmospheric humidity can impact the dynamics of polymers at the segmental and the chain level. By using tools like microscopy, ellipsometry and molecular dynamic …

A Trusted Platform For Unmanned Aerial Vehicle-Based Bridge Inspection Management System, Hwapyeong Song

Theses, Dissertations and Capstones

Bridge inspection has a pivotal role in assuring the safety of critical structures constituting society. However, high cost, worker safety, and low objectivity of quality are classic problems in traditional visual inspection. Recent trends in bridge inspection have led to a proliferation of research utilizing Unmanned Aerial Vehicles (UAVs). This thesis proposes a Trusted Platform for Bridge Inspection Management System (Trusted-BIMS) for safe and efficient bridge inspection by proving the UAV-based inspection process and improving the prototype of the previous study. Designed based on a Zero-Trust (ZT) strategy, Trusted-BIMS consist of (1) a database-driven web framework with security features for …

Adjust-A-Ramp, Taylor Sharrits, Courtney Banks, Emily Beck, Jazmin Buenrostro

Williams Honors College, Honors Research Projects

Adjust-A-Ramp is a portable ramp designed to ensure the safety of consumers and prevention of damage to cars, specifically towards low profile cars. A low-profile vehicle includes any vehicle that has a clearance off the ground of 6.5 inches or less. Advantages of low-profile vehicles include improved handling, better braking, increased fuel efficiency, increased stability, and an overall luxury aesthetic. The reduced tire size increases grip on smooth surfaces with better wheel response, creating a fast, more efficient ride. The simple tire tread patterns and the stiff sidewalls allow for lower rolling resistance which increases fuel economy. The Adjust-A-Ramp can …

Spring 2022 Superhydrophobic Materials, T. Leo Liu

Science and Engineering Saturday Seminars

Many natural surfaces, such as lotus leaves and a water strider’s leg, have shown striking water repellency so that they remain clean and dry even in “dirty” habitats. Such water repellency is called superhydrophobicity, which has stimulated lots of science and engineering imagination for self-cleaning windows, never dirty clothes, drag-reduction swimming suits, etc. In this workshop, we will use superhydrophobicity as a model to guide an integrative teaching and learning experience through hands-on experiments, critical thinking, basic science, as well as a lecture on state-of-the-art research discoveries. The objectives of this workshop are to (1) stimulate student curiosity and imagination …

Me-Em Enewsbrief, December 2021, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical Engineering-Engineering Mechanics eNewsBrief

No abstract provided.

Rational Design Of Flexible And Stretchable Electronics Based On 3d Printing, Yuanhang Yang

Theses and Dissertations

Flexible and stretchable electronics have been considered as the key component for the next generation of flexible devices. There are many approaches to prepare the devices, such as dip coating, spin coating, Mayer bar coating, filtration and transfer, and printing, etc. The effectiveness of these methods has been proven, but some drawbacks cannot be ignored, such as lacking pattern control, labor consuming, requiring complex pretreatment, wasting conductive materials, etc.

In this investigation, we propose to adopt 3D printing technology to design flexible and stretchable electronics. The objective is to rationally design flexible and stretchable sensors, simplify the preparation process, form …

A Computational Exploration Of The Scandate Cathode Surface, Shankar Miller-Murthy

Theses and Dissertations--Chemical and Materials Engineering

The exact surface configuration of scandate cathodes has been a point of contention for the materials community for a long time. Without proper understanding of it and the related structures and emission mechanisms, scandate cathodes remain patchy and unreliable emitters. Thus, density functional theory techniques were applied to various potential surface arrangements and found that there are several low-energy surfaces with low work functions that incorporate a scandium interlayer between tungsten and oxygen or otherwise have a scandium-on-tungsten structure. Furthermore, it was discovered that adding a monolayer of scandium directly to a tungsten surface is surprisingly favorable, thermodynamically. While none …

Some Investigations Of Phase Transitions In Rod-Like Macro-Molecules And Fibrous Gels, Chuanpeng Sun

Publicly Accessible Penn Dissertations

Two problems pertaining to solid-solid phase transitions are presented here.First, we conduct Langevin dynamics calculations on a chain of masses and bistable springs in a viscous fluid, and extract a temperature dependent kinetic relation by observing that the dissipation at a phase boundary can be estimated by performing an energy balance. Using this kinetic relation we solve boundary value problems for a bistable bar immersed in a constant temperature bath and show that the resultant force-extension relation matches very well with the Langevin dynamics results. We estimate the force fluctuations at the pulled end of the bar due to thermal …

Complex Systems Engineering: Designing Advanced Functions In Dynamical And Mechanical Systems, Jinsu Kim

Publicly Accessible Penn Dissertations

From computation in neural networks to allostery in proteins, numerous natural and artificial systems are comprised of many interacting parts that give rise to advanced functions. To study such complex systems, a diverse array of interdisciplinary tools have been developed that relate the interactions of existing systems to their functions. However, engineering the interactions to perform designed functions in novel systems remains a significant challenge due to the nonlinearities in the interactions and the vast dimensionality of the design space. Here we develop design principles for complex dynamical and mechanical systems at the lowest level of their microstate interactions. In …

Metal-Air Power Sources With Hydrogel Electrolytes For Long Endurance Robots, Min Wang

Publicly Accessible Penn Dissertations

To power electronics for long durations, batteries need to be recharged because they store only a small amount of total energy, which is limited by the mass of energy storage materials in the battery electrodes. Harvesters can provide longer continuous energy, but their limited power and need for precise operating conditions severely restricts their application in off-grid robots, microelectronics, and internet connected devices. In this dissertation, we designed a new strategy for powering robots and electronics by electrochemically scavenging energy from metal surfaces, which breaks energy storage scaling laws by allowing robots and electronics to extract energy from large volumes …

Using Time-Resolved Electron Microscopy And Data Analytics To Quantify The Evolution Of Supported Metal Nanoparticles, James Peter Horwath

Publicly Accessible Penn Dissertations

Supported precious metal nanoparticles are important heterogeneous catalysts for both industrial processes and commercial products. Their high catalytic activity stems from their high surface free energy and under-coordinated surfaces, however these same properties destabilize the particles and cause them to grow and deactivate. While research studying the degradation of supported catalysts has been undertaken for decades, the exact mechanisms at play, and how the vary with reaction conditions, are not well understood. Advances in experimental instrumentation have positioned Transmission Electron Microscopy (TEM) as an ideal tool for characterizing the dynamic evolution of these nanoscale systems with both high spatial and …