Mechanical Engineering Commons^™

Fluid Mechanics Of Air Recycling And Filtration For Indoor Airborne Transmission, K. A. Krishnaprasad, J. S. Salinas, ‪Nadim Zgheib, S. Balachandar

Mechanical Engineering Faculty Publications

We present a statistical framework to account for effects of recycling and filtration in ventilation systems for the estimation of airborne droplet nuclei concentration in indoor spaces. We demonstrate the framework in a canonical room with a four-way cassette air-conditioning system. The flow field within the room is computed using large eddy simulations for varying values of air changes per hour, and statistical overloading is used for droplet nuclei, which are tracked with a Langevin model accounting for sub-grid turbulence. A key element is to break up the path that a virus-laden droplet nucleus can take from the time it …

Dynamic Thermal Model Development Of Direct Methanol Fuel Cell, Mohammad Biswas, Tabbi Wilberforce

Mechanical Engineering Faculty Publications and Presentations

Direct methanol fuel cell (DMFC) is fueled with liquid methanol coupled with air to produce power at reasonably lower operational conditions while resulting in by-products of carbon dioxide and water, which is more environmentally friendly. Due to the complexity associated with the performance of direct methanol fuel cell, the application of artificial neural network (ANN) can significantly predict the characteristic performance of the cells. Nevertheless, limited studies have delved into the exploration of artificial neural network in the prediction of the transient characteristics of direct methanol fuel cells. The current study however presents a detailed investigation into the prediction of …

Coaxial Jets With Disparate Viscosity: Mixing And Laminarization Characteristics, Mustafa Usta, M. R. C. Ahmad, G. Pathikonda, I. Khan, P. Gillis, D. Ranjan, C. K. Aidun

Mechanical Engineering Faculty Publications

Mixing of fluids in a coaxial jet is studied under four distinct viscosity ratios, m = 1, 10, 20 and 40, using highly resolved large-eddy simulations (LES), particle image velocimetry and planar laser-induced fluorescence. The accuracy of predictions is tested against data obtained by the simultaneous experimental measurements of velocity and concentration fields. For the highest and lowest viscosity ratios, standard RANS models with unclosed terms pertaining to viscosity variations are employed. We show that the standard Reynolds-averaged Navier-Stokes (RANS) approach with no explicit modelling for variable-viscosity terms is not applicable whereas dynamic LES models provide high-quality agreement with the …

Developing Test Methods For Compression After Lightning Strikes, Xiaodong Xu, Scott L. J. Millen, Juhyeong Lee, Gasser Abdelal, Daniel Mitchard, Michael R. Wisnom, Adrian Murphy

Mechanical and Aerospace Engineering Faculty Publications

Research into residual strength after lightning strike is increasing within the literature. However, standard test methods for measuring residual compressive strength after lightning strikes do not exist. For the first time, a systematic experimental study is undertaken to evaluate modifications necessary to standard Compression After Impact (CAI) specimen geometry and test jig design to induce specimen failure at the lightning damage region. Four laboratory generated lightning strike currents with peak amplitudes ranging from 25 to 100 kA have been studied. Test set-up modifications were made considering the scale of the lightning damage and its potential proximity to specimen edges. Specimen …

A 3d Bioprinted Hydrogel Microfluidic Device For Screening Applications, Anant Bhusal

Theses and Dissertations

The microfluidic enabled the integration of engineered miniaturized tissue models for drug screening. Conventional polydimethylsiloxane or plastic-based devices require multiple fabrication steps, which are challenging. We developed a 3D bioprinting approach to create prototypes of hydrogel-based multi-material microfluidic devices integrated with microtissue models. The approach utilizes poly(ethylene glycol) diacrylate and gelatin-methacryloyl to create microfluidic chips using multi-material bioprinting capacity with a high resolution of 15µm on x-y and 50µm on the z-axis and post-printing viability of >90%. We demonstrated easy regulation of stiffness from 24±5 kPa to 1,180±9 kPa and burst pressure from 16±1kPa to 256±19 kPa in the chip …

Static And Dynamic Analysis Of A Bistable Frequency Up-Converter Piezoelectric Energy Harvester, Mohammad Atmeh, Alwathiqbellah Ibrahim, Abdallah Ramini

Mechanical Engineering Faculty Publications and Presentations

Using energy harvesting to convert ambient vibrations efficiently to electrical energy has become a worthy concept in recent years. Nevertheless, the low frequencies of the ambient vibrations cannot be effectively converted to power using traditional harvesters. Therefore, a frequency up-conversion harvester is presented to convert the low-frequency vibrations to high-frequency vibrations utilizing magnetic coupling. The presented harvester consists of a low-frequency beam (LFB) and a high-frequency beam (HFB) with identical tip magnets facing each other at the same polarity. The HFB, fully covered by a piezoelectric strip, is utilized for voltage generation. The dynamic behavior of the system and the …

Electric Field-Assisted Nanofiltration For Pfoa Removal With Exceptional Flux, Selectivity, And Destruction, Yangyuan Ji, Youn Jeong Choi, Yuhang Fang, Hoang Son Pham, Alliyan Tan Nou, Linda S. Lee, Junfeng Niu, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Per- and polyfluoroalkyl substances (PFAS) pose significant environmental and human health risks and thus require solutions for their removal and destruction. However, PFAS cannot be destroyed by widely used removal processes like nanofiltration (NF). A few scarcely implemented advanced oxidation processes can degrade PFAS. In this study, we apply an electric field to a membrane system by placing a nanofiltration membrane between reactive electrodes in a crossflow configuration. The performance of perfluorooctanoic acid (PFOA) rejection, water flux, and energy consumption were evaluated. The reactive and robust SnO2–Sb porous anode was created via a sintering and sol–gel process. The characterization and …

An Alternate Dimensionless Form Of The Linearized Rigid-Body Aircraft Equations Of Motion With Emphasis On Dynamic Parameters, Douglas F. Hunsaker, Benjamin C. Moulton

Mechanical and Aerospace Engineering Student Publications and Presentations

The equations of motion for an aircraft can be linearized about a reference condition within the assumptions of small disturbances and linear aerodynamics. The resulting system of equations is typically solved to obtain the eigenvalues and eigenvectors that describe the small disturbance motion of the aircraft. Results from such an analysis are often used to predict the rigid-body dynamic modes of the aircraft and associated handling qualities. This process is typically carried out in dimensional form in most text books, or in nondimensional form using dimensionless parameters rooted in aerodynamic theory. Here we apply Buckingham’s Pi theorem to obtain nondimensional …

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 …

Comparing The Performance Of Different Machine Learning Models In The Evaluation Of Solder Joint Fatigue Life Under Thermal Cycling, Jason Scott Ross

Dissertations and Theses

Predicting the reliability of board-level solder joints is a challenging process for the designer because the fatigue life of solder is influenced by a large variety of design parameters and many nonlinear, coupled phenomena. Machine learning has shown promise as a way of predicting the fatigue life of board-level solder joints. In the present work, the performance of various machine learning models to predict the fatigue life of board-level solder joints is discussed. Experimental data from many different solder joint thermal fatigue tests are used to train the different machine learning models. A web-based database for storing, sharing, and uploading …

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 …

Demonstrating Non-Isothermal Vacuum Membrane Air Dehumidification For Efficient Next-Generation Air Conditioning, Andrew J. Fix, Shivam Gupta, James E. Braun, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Vacuum membrane air dehumidification has gained significant interest in recent years as a highly efficient means of air dehumidification. Prior theoretical modeling work by the authors 1 introduced the Active Membrane Energy Exchanger (AMX) concept, which combines active heat exchange and vacuum membrane dehumidification into one non-isothermal system, and found that it could outperform other air conditioning technologies under many conditions. However, no experimental literature exists on combining active heat exchangers and vacuum membrane dehumidification. The goal of the present study is to evaluate the dehumidification (mass transfer) performance of the AMX concept relative to isothermal membrane dehumidification through three …

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 …

Effect Of Austenization And Repeated Quenching On The Microstructures And Mechanical Properties Of Wear-Resistant Steel, Yanuar Nugraha, Myrna Ariati Mochtar

Journal of Materials Exploration and Findings

This study was focused on determining the effect of repeated austenitization and quenching on mechanical properties and microstructure. The experiment was carried out in a rolled quencher facility with a heat treatment process of one to two times, with parameters of an austenizing temperature of 9500C and quenching at a temperature of 8500C with pressurized water media. Testing of specimens, including microstructure observations and hardness testing. The repeated heat treatment process showed an increase in hardness of 0.79% on one-time repeated heat treatment and 1.65% on two repeated heat treatments. This occurs due to the presence accompanied by refinement of …

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 …

Using Dielectric Scatters To Selectively Excite Embedded Eigenstates In Cavity Resonators, Olugbenga Joshua Gbidi

Theses and Dissertations

Bound states in the continuum (BICs) are waves that remain in the continuous spectrum of radiating waves that carry energy, however, still localized within the spectrum. BICs, also embedded eigenmodes, exhibit high quality factors that have been observed in optical and acoustic waveguides, photonic structures, and other material systems. Presently, there are limited means to select these BICs in terms of the quality factor and their excitation. In this work, we show that a different type of BIC, Quasi-BICs (Q-BICs), in open resonators can have their quality attuned by introducing embedded scatters. Using microwave cavities and dielectric scatters as an …

Probing The Influence Of Surface Chemical Functionalization On Graphene Nanoplatelets-Epoxy Interfacial Shear Strength Using Molecular Dynamics, Hashim Al Mahmud, Sagar Patil, Matthew Radue, Gregory Odegard

Michigan Tech Publications, Part 1

In this work, a characterization study of the interfacial interaction between different types of graphene nanoplatelets and an epoxy matrix is computationally performed. To quantify the discrete mutual graphene–epoxy “interfacial interaction energy” (IIE) within the nanocomposite, molecular dynamics simulations with a reactive force field are performed on a localized model of the suggested nanocomposite. Pull-out molecular dynamics simulations are also performed to predict the interfacial shear strength between the two constituents. The results indicate a significant increase in interfacial adhesion of functionalized nanoplatelets with the hosting epoxy matrix relative to virgin graphene nanoplatelets. The obtained results also demonstrate a dramatic …

Concurrent Validity Study Of 3d Motion Measurement Systems: Vicon Vs. Xsens, Pias Das

Masters Theses

As the Inertial Measurement System (IMS) being a potential alternative to the Optoelectronic Measurement System (OMS) in terms of capturing comprehensive and objective musculoskeletal data, they need to be verified concurrently with the OMS before we start using the IMS in clinical motion analysis. To achieve this, a concurrent validity experiment of the Xsens system (IMS) in comparison to the Vicon system (OMS) was conducted for both upper and lower extremity movements during walk, squat, and lateral lunge (left and right) to quantify the degree of similarity of kinematic data between the two systems by direct comparison, root mean square …

Gesture-Based American Sign Language (Asl) Translation System, Kayleigh Moore, Stefano Pecile, Mahdi Yazdanpour

Posters-at-the-Capitol

According to the World Health Organization (WHO), over 5% of the world's population experiences severe hearing loss. Approximately 9 million people in the U.S. are either functionally deaf or have mild-to-severe hearing loss. In this research, we designed and implemented a translation interface which turns American Sign Language (ASL) gestures captured from a pair of soft robotic gloves into text and speech instantaneously.

We used a combination of flex sensors, tactile sensors, and accelerometers to recognize hand gestures and to record hand and fingers positions, movements, and orientations. The digitized captured gestures were then sent to our proposed translation interface …

The Simulation Of Elastic Wave Propagation In Presence Of Void In The Subsurface, Brittany Ballengee

Theses, Dissertations and Capstones

Underground voids, whether man-made (e.g., mines and tunnels) or naturally occurring (e.g., karst terrain), can cause a variety of threats to surface activity. Therefore, it is important to be able to locate and characterize a potential void in the subsurface so that mitigating measures can be taken. In real-world environments, the subsurface properties and the existence of a void is not known, so the problem is challenging to solve. The numerical analysis conducted in this study takes a step toward understanding the seismic response with and without a void in various types of domains. The Finite Difference Method (FDM) and …

Additively Manufactured Polymeric Surface-Based Lattice Structures For Vibration Attenuation, Imabin Kelvin Ekpelu

Browse all Theses and Dissertations

The focus of this study was to select triply periodic minimal surface (TPMS) structures made of 3D-printed polymers. The primary variables in this study were: TPMS shape, lattice volume ratio, and lattice material. Vibration absorption was characterized by damping ratio via transmissibility at the system’s natural frequency. The vibration testing was performed using an electro-dynamic shaker, a known mass, an input/control accelerometer, and an output/response accelerometer. The 3D-printed absorber/lattice was mounted to the shaker baseplate and a mass will be mounted on top of the absorber. One accelerometer will be mounted to the shaker baseplate and the other will be …

Combat Robot, Riley Buxton

All Undergraduate Projects

In the sport of combat robotics, the goal is to build a robot that can incapacitate an opposing robot before it becomes incapacitated itself. For this project, a combat robot was designed and tested to compete in Western Allied Robotics’ first competition at Central Washington University. The robot was built to compete in the beetle weight class which means the entire robot had to weigh less than 3 lbs.

To ensure the robot was competitive, a number of important design choices were made. Firstly, an effort was made to ensure that the design was simple and easy to take apart …

Jcati Carbon Fiber Recycler- Fiber Conveyance, Taylor Miller

All Undergraduate Projects

Sponsored by the Joint Center for Aerospace Technology Innovation (JCATI), this project stems from a partnership between Central Washington University’s Mechanical Engineering Technology program and The Boeing Company. The goal of this partnership was to create a device that repurposes carbon fiber from wing trimmings from the 777. The device features four different students’ projects including the crusher, shredder, oven heating system, and the fiber conveyance system; the focus of this project. The JCATI Carbon Fiber Recycler needed a device to transport material from the shredder to the oven to make for an easier, more seamless production process. To solve …

Rc Baja – Drivetrain & Chassis, Tyler Clerf

All Undergraduate Projects

Two of the most important subsystems of a vehicle are the drivetrain and chassis. The drivetrain is responsible for transmitting the power from the power source to the wheels. The chassis provides a sturdy host for all components. An optimal drivetrain will most often reduce the output speed and increase the torque from the motor, while minimizing losses. The ideal chassis will have minimal deflection with easy-to-use mounting points. The vehicle being created will compete in the CWU RC BAJA competition as well.

The analyses are the foundation of any engineering project. For this project Mechanical Design, Statics, and Dynamics …

Balsa Wood Bridge Senior Project, Ryan Moe

All Undergraduate Projects

For all of human history, people have been working to increase efficiency. This project followed in that pursuit by forcing engineers to create a 400 mm long bridge out of only balsa wood and glue that could withstand over 20 kgs of force with the bridge weighing a maximum of only 85 grams. The bridge also needed to have a lifting mechanism to raise it 140 mm above the starting position.

To accomplish this task, a strong truss needed to be built. Balsa wood is strong in compression so a truss with more beams in compression was used. Statics was …

Nasa Student Launch Payload Deployment, Kallysta Ray

All Undergraduate Projects

For the NASA Student Launch Competition, a deployment system was created to deploy the payload of the rocket. To accomplish this the deployment system was designed, analyzed, manufactured, and tested to meet the requirements from the NASA Competition. The requirements included deployment of the payload as well as staying within 4 pounds. The project requirements were researched and each of the proposed components had analyses completed. The analyses included weight calculations, stress, and deflection analyses using statics, mechanics of materials, and dynamics. There were many discussions throughout the project between the teammates to ensure all components of the payload and …

Jack And Alex Rc-Baja, Alex Vornbrock

All Undergraduate Projects

Teams of two mechanical engineering students were tasked with the construction of an RC Baja car qualified by the rules and regulations of the Baja competition as well as specifications set by the individual team member for their portion of the vehicle. This proposal focuses on the Chassis and Drivetrain of the vehicle while team member Jack Stutz oversaw the steering and suspension. Teams will compete against each other in various modes to determine the best vehicles of the competitors. The chassis was made of standard aluminum, the remaining parts made by the students were made with PLA; both materials …

F-1/10th, Max Otterby

All Undergraduate Projects

Team members Nate and Max were tasked with designing, building, and testing an RC controlled vehicle to complete in a competition. This competition consists of an off-road course, on road course, and an obstacle course. The team set out to win this competition by creating a more than capable vehicle for the competition. This engineering report will cover Max’s contributions to the project.

The team was split into two roles. Max taking on steering and suspension, Nate taking on drivetrain and chassis. Each team member took responsibility for the design and construction of those systems. The design chosen was based …

Nasa Student Launch - Payload, Eli Kirk

All Undergraduate Projects

A team of mechanical engineering, physics, and computer science students from Central Washington University have constructed a fully functional subscale model rocket to be flown at the NASA Student Launch competition. The rocket’s payload was designed to open the nose cone and take a photo of the rocket’s surroundings after descending from the launch. Smaller parts were constructed through machining and 3D printing that will be added to the purchased major component, the linear actuator, in order to perform the required tasks. These tasks are signaled by an attached electronics board, which will receive an RF command remotely, execute code, …

Jack & Alex Rc Baja, Jack Stutz

All Undergraduate Projects

There are paramount necessities to build an RC car such as the steering and suspension. Without either, the vehicle will not be able to ascertain basic movement characteristics. The team will compete in the RC Baja competition with the other students which will have various challenges and obstacles that they will endure. The device must be able to complete tests that will prove competence for the competition. By using knowledge of prior classes and experience, the team will produce a functional device for the event. Mechanics of materials and statics were used to determine the bending strength of the control …