Mechanical Engineering Commons^™

Coupling Numerical Analysis Of Vibration And Thermal Buckling Of An Automotive Brake Disc, Joseph-Shaahu Shaahu

Electronic Theses and Dissertations

An engaged brake system generates high temperature gradients in the brake rotor and brake pads. This high temperature gradient in turn induces thermal buckling. During high speed rotation, vibration is likely to occur in the system. In terms of a brake disc vibration will occur when there is a misalignment of the brake disc or thermoelastic instability (hot spot) forms on the brake rotor. Coupled and uncoupled problems of thermal buckling and vibration of a brake disc are analyzed and presented using finite element analysis in this paper. Thermal buckling depends on the direction of the high temperature gradient. Having …

From Statistical Correlations To Stochasticity And Size Effects In Sub-Micron Crystal Plasticity, Hengxu Song, Stefanos Papanikolaou

Faculty & Staff Scholarship

Metals in small volumes display a strong dependence on initial conditions, which translates into size effects and stochastic mechanical responses. In the context of crystal plasticity, this amounts to the role of pre-existing dislocation configurations that may emerge due to prior processing. Here, we study a minimal but realistic model of uniaxial compression of sub-micron finite volumes. We show how the statistical correlations of pre-existing dislocation configurations may influence the mechanical response in multi-slip crystal plasticity, in connection to the finite volume size and the initial dislocation density. In addition, spatial dislocation correlations display evidence that plasticity is strongly influenced …

Ua66/9/1 Ogden College Of Science & Engineering Engineering Administration, Wku Archives

WKU Archives Collection Inventories

No abstract provided.

Computational Fluid Dynamics Investigation Of A Novel Hybrid Comprehensive Stage Ii Operation For Single Ventricle Palliation, Marwan Hameed

Electronic Theses and Dissertations

Hypoplastic left heart syndrome (HLHS) is a type of heart defect where the left ventricle is underdeveloped or not developed, resulting in only a single functioning right ventricle. Approximately 7.5% of patients with congenital heart disease are born with a single ventricle (SV) which is accompanied by a spectrum of other malformations such as atrophied ascending aorta, atrial septal defects, and ventricular septal defects (VSD). The existing three-hybrid staged surgical approach serving as a palliative treatment for this anomaly entails multiple complications and achieves a survival rate of only 50%. To reduce the trauma associated with the second stage of …

A Low-Cost, Open-Source Digital Stripchart Recorder For Chromatographic Detectors Using A Raspberry Pi, Eric Constans, Samuel Foster, Michael Alirangues, Joseph Naese, James Grinias

Faculty Publications - Mechanical Engineering

No abstract provided.

Compressible And Choked Flows In Rotating Passages, Nolan J. Dyck, Anthony G. Straatman

Mechanical and Materials Engineering Publications

No abstract provided.

A Numerical Approach For Determining The Resistance Of Fine Mesh Filters, Anthony Sherratt, Christopher T. Degroot, Anthony G. Straatman, Domenico Santoro

Mechanical and Materials Engineering Publications

No abstract provided.

Robust Impedance Control Of A Four Degree Of Freedom Exercise Robot, Santino Joseph Bianco

ETD Archive

The CSU 4OptimX exercise robot provides a platform for future research into advanced exercise and rehabilitation. The robot and its control system will autonomously modify reference trajectories and impedances on the basis of an optimization criterion and physiological feedback. To achieve this goal, a robust impedance control system with trajectory tracking must be implemented as the foundational control scheme. Two control laws will be compared, sliding mode and H-infinity control. The above robust control laws are combined with underlying impedance control laws to overcome uncertain plant model parameters and disturbance anomalies affecting the input signal. The sliding mode control law …

A Reticulation Of Skin-Applied Strain Sensors For Motion Capture, Christopher A. Schroeck

ETD Archive

The purpose of this research is to develop a system of motion capture based on skin-applied strain sensors. These elastic sensors are of interest because they can be applied to the body without restricting motion and are well suited to operate in more practical environments, such as sports fields, gymnasiums, and outdoor areas. This combination is currently not available in the field of motion capture. The current issues with strain sensor motion capture technology is the accurate is not sufficient for motion analysis and axial rotation monitoring of joints is not available. This project will build and test a sensor …

Robotic Devicewith Compact Joint Design And Related Systems And Methods, Tom Frederick, Eric Markvicka, Shane Michael Farritor, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various robotic and/or in vivo medical devices having compact joint configurations. Other embodiments relate to various medical device components, including forearms having grasper or cautery end effectors, that can be incorporated into certain robotic and/or in vivo medical devices.

Flaw Detection With Ultrasonic Backscatter Signal Envelopes, Yongfeng Song, Christopher M. Kube, Zuoxiang Peng, Joseph A. Turner, Xiongbing Li

Department of Mechanical and Materials Engineering: Faculty Publications

Ultrasound is a prominent nondestructive testing modality for the detection, localization, and sizing of defects in engineering materials. Often, inspectors analyze ultrasonic waveforms to determine if echoes, which stem from the scattering of ultrasound from a defect, exceed a threshold value. In turn, the initial selection of the threshold value is critical. In this letter, a time-dependent threshold or upper bound for the signal envelope is developed based on the statistics governing the scattering of ultrasound from microstructure. The utility of the time-dependent threshold is demonstrated using experiments conducted on sub-wavelength artificial defects. The results are shown to enhance current …

Glocal Integrity In 420 Stainless Steel By Asynchronous Laser Processing, Michael P. Sealy, Haitham Hadidi, Cody Kanger, X. L. Yan, Bai Cui, J. A. Mcgeough

Department of Mechanical and Materials Engineering: Faculty Publications

Cold working individual layers during additive manufacturing (AM) by mechanical surface treatments, such as peening, effectively “prints” an aggregate surface integrity that is referred to as a glocal (i.e., local with global implications) integrity. Printing a complex, pre-designed glocal integrity throughout the build volume is a feasible approach to improve functional performance while mitigating distortion. However, coupling peening with AM introduces new manufacturing challenges, namely thermal cancellation, whereby heat relaxes favorable residual stresses and work hardening when printing on a peened layer. Thus, this work investigates glocal integrity formation from cyclically coupling LENS® with laser peening on 420 stainless steel.

The Role Of Low-Level Image Features In The Affective Categorization Of Rapidly Presented Scenes, L. Jack Rhodes, Matthew Rios, Jacob M. Williams, Gonzalo Quinones, Prahalada K. Rao, Vladimir Miskovic

Department of Mechanical and Materials Engineering: Faculty Publications

It remains unclear how the visual system is able to extract affective content from complex scenes even with extremely brief (< 100 millisecond) exposures. One possibility, suggested by findings in machine vision, is that low-level features such as unlocalized, two-dimensional (2-D) Fourier spectra can be diagnostic of scene content. To determine whether Fourier image amplitude carries any information about the affective quality of scenes, we first validated the existence of image category differences through a support vector machine (SVM) model that was able to discriminate our intact aversive and neutral images with ~ 70% accuracy using amplitude-only features as inputs. This model allowed us to confirm that scenes belonging to different affective categories could be mathematically distinguished on the basis of amplitude spectra alone. The next question is whether these same features are also exploited by the human visual system. Subsequently, we tested observers’ rapid classification of affective and neutral naturalistic scenes, presented briefly (~33.3 ms) and backward masked with synthetic textures. We tested categorization accuracy across three distinct experimental conditions, using: (i) original images, (ii) images having their amplitude spectra swapped within a single affective image category (e.g., an aversive image whose amplitude spectrum has been swapped with another aversive image) or (iii) images having their amplitude spectra swapped between affective categories (e.g., an aversive image containing the amplitude spectrum of a neutral image). Despite its discriminative potential, the human visual system does not seem to use Fourier amplitude differences as the chief strategy for affectively categorizing scenes at a glance. The contribution of image amplitude to affective categorization is largely dependent on interactions with the phase spectrum, although it is impossible to completely rule out a residual role for unlocalized 2-D amplitude measures.

Test 2215: Kubota M7-152, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S1180 Fendt 939, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Spatiotemporal Analysis Of Nonaffine Displacements In Disorderedsolids Sheared Across The Yielding Point, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The time evolution and spatial correlations of nonaffine displacements in deformed amorphous solids are investigated using molecular dynamics simulations. The three-dimensional model glass is represented via the binary mixture, which is slowly annealed well below the glass transition temperature and then sheared at a constant strain rate. It is shown that with increasing strain,the typical size of clusters of atoms with large nonaffine displacements increases, and these clusters remain spatially homogeneously distributed, until the yielding point when mobile atoms become localized within a system-spanning shear band. Furthermore, the yielding transition is associated with an abrupt change in the spatial correlation …

Autonomous Vehicles: Autodriver Algorithm And Vehicle Dynamics, Hormoz Marzbani, Hamid Khayyam, Ching Nok, Catter To, Đại Võ Quốc, Reza N. Jazar

Staff Publications

A given road can be expressed mathematically in a global (or world) coordinate frame. Following the road can be substituted by following the loci of its curvature center and turning at the right circle of curvature. Considering that a vehicle in motion is always in turn about an instantaneous rotation center relative to the ground, an autonomous vehicle capable of following a given path by coinciding the rotation center of vehicle at every moment on the curvature center of the road could be designed. The dynamic reactions of the vehicle influence its path of motion and make its rotation center …

Compliant Surgical Graspers And Methods Of Making And Using, Carl Nelson, Alan Goyzueta

Department of Mechanical and Materials Engineering: Faculty Publications

This disclosure describes compliant graspers for use in endoscopic surgeries.

Self-Powered Ghz Solution-Processed Hybrid Perovskite Photodetectors, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

Organic-inorganic hybrid perovskite (OIHP) based photo-responsive devices include an OIHP active layer disposed between a cathode layer and an anode layer, and an electron extraction layer disposed between the cathode layer and the active layer. The electron extraction layer includes a layer of C₆₀ directly disposed on the active layer. The active layer includes an organometal trihalide perovskite layer (e.g., CH₃NH₃PbI₂X, where X includes at least one of Cl, Br, or I).

9r Phase Enabled Superior Radiation Stability Of Nanotwinned Cu Alloys Via In Situ Radiation At Elevated Temperature, Cuncai Fan, Dongyue Xie, Jin Li, Zhongxia Shang, Youxing Chen, Sichuang Xue, Jian Wang, Meimei Li, Anter El-Azab, Haiyan Wang, Xinghang Zhang

Department of Mechanical and Materials Engineering: Faculty Publications

Nanotwinned metals exhibit outstanding radiation tolerance as twin boundaries effectively engage, transport and eliminate radiation-induced defects. However, radiation-induced detwinning may reduce the radiation tolerance associated with twin boundaries, especially at elevated temperatures. Here we show, via in-situ Kr ion irradiation inside a transmission electron microscope, that 3 at. % Fe in epitaxial nanotwinned Cu (Cu₉₇Fe₃) significantly improves the thermal and radiation stability of nanotwins during radiation up to 5 displacements-per-atom at 200 °C. Such enhanced stability of nanotwins is attributed to a diffuse 9R phase resulted from the dissociation of incoherent twin boundaries in nanotwinned Cu …

Relative Contributions Of Intracranial Pressure And Intraocular Pressure On Lamina Cribrosa Behavior, Junfei Tong, Deepta Ghate, Sachin Kedar, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Purpose. To characterize the relative contributions of intraocular pressure (IOP) and intracranial pressure (ICP) on lamina cribrosa (LC) behavior, specifically LC depth (LCD) and LC peak strain. Methods. An axially symmetric finite element model of the posterior eye was constructed with an elongated optic nerve and retro-orbital subarachnoid space ensheathed by pia and dura mater. -e mechanical environment in LC was evaluated with ICP ranging from 5 to 15mmHg and IOP from 10 to 45 mmHg. LCD and LC peak strains at various ICP and IOP levels were estimated using full factorial experiments. Multiple linear regression analyses were …

System Dynamics And Control, Benjamin Liaw

Open Educational Resources

Model development with applications to mechanical engineering systems. First and higher order system responses. Laplace transform, transfer functions and block diagrams. Frequency response and vibration. Introduction to feedback control. Concepts of PID control, tuning and compensation. Routh-Hurwitz stability. Control analysis and design using various graphical methods such as root locus, Bode diagram, Nyquist plot and Nichols chart. Hands-on experiments include dynamics and controls of mechanical, servo motor, fluid level/flow, pneumatic and temperature processing systems and vibration of various degree-of-freedom systems.

Shear Band Formation In Amorphous Materials Under Oscillatoryshear Deformation, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The effect of periodic shear on strain localization in disordered solids is investigated using molecular dynamics simulations. We consider a binary mixture of one million atoms annealed to a low temperature with different cooling rates and then subjected to oscillatory shear deformation with a strain amplitude slightly above the critical value. It is found that the yielding transition occurs during one cycle but the accumulation of irreversible displacements and initiation of the shear band proceed over larger number of cycles for more slowly annealed glasses. The spatial distribution and correlation function of nonaffine displacements reveal that their collective dynamics changes …

Dual Axis Solar Tracker: Trends, Influence & Impact, Alazone Smith

Undergraduate Honors Theses

This supplementary document examines the international relevance and impact of the device in the Central Washington University, M.E.T. Senior Project entitled, “Dual-Axis Solar Tracker”. This is done so by analyzing the data collected from the device, as well as related trends in society, and establishing connections between the device’s viability and its impact within the society. Climate change, the solar industry, technology, policy, and market are the main topics of research within this document to provide background and context for the methods of analysis. Following intensive research, two major research strategies were implemented: (1) the data collected from the device …

Prosthetic Hand: Articulation, Michael Funk

All Undergraduate Projects

This group project objective was about developing a low cost articulated prosthetic hand. This project was developed in two parts: articulation and body. The development of the articulation started as a simple system that has developed into a more complex system push and pull system. The development cycle helped define the systems used in the prosthetic. The movement/articulation system needed to not only move parts of the hand but also hold objects with the appropriate gripping power. The finger also has to be able close in a reasonable amount of time. The articulation is driven by motors attached to small …

Custom Foot Prosthetic: Diabetic Care, Chandler Streuli

All Undergraduate Projects

Across the United States there are people every day who lose their toes to diabetes or to loss of circulation within their legs. The problem becomes building a more cost effective and efficient prosthetic for these individuals. The prosthetics that are used for medical purposes are often costly, especially without the help of insurance. The new prosthetic was designed to be taken in and out of shoes so that it is fast and easy for the user to move the device from shoe to shoe. The manufacturing method for this project was using a 3D printer to build the initial …

Electrathon: Body, Ryan Shiner

All Undergraduate Projects

• The Electrathon Vehicle project is an ongoing project that dates back to 2012. This vehicle will be raced at events to see how many laps it can complete on a single battery charge. The existing body for the Central Washington University Electrathon vehicle required modifications to fit over the current frame. These modifications were required because the rear suspension design had changed. The rear panel of the body interfered with the rear suspension. Using a rotary cutting wheel, the panel was slotted so the body could slide over the suspension and drive chain. Additionally, spacers for various sizes were needed …

Electrathon Vehicle: Drive Train, Luis Hernandez

All Undergraduate Projects

Electrathon America is a competition where electrical vehicles (EV) race against electrical attrition and time. Therefore a vehicle must not only be light and fast but also efficient. EV Drivetrain (the assembly which moves the vehicle by transfer of power from motor to wheel) must be able to transfer enough power in order to move a 100 pound vehicle and 180 pound driver 45 miles per hour. Components for the drivetrain and manufacturing must not exceed the $500 budget. In order to move the vehicle, three different methods to transfer power were considered: chain, belt, and shaft (rotating stick). It …

Mechanical Characterization Of Anisotropic Fused Deposition Modeled Polylactic Acid Under Combined Monotonic Bending And Torsion Conditions, Aaron T. Santomauro

Honors Undergraduate Theses

Mechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected to multiple monotonic loading conditions. Although empirical data has previously been captured for multi-oriented PLA under tensile and compressive loading conditions, the data has yet to be applied with regard to a representative component …

Structural Relaxation Of Porous Glasses Due To Internal Stresses And Deformation Under Tensile Loading At Constant Pressure, Nikolai V. Priezjev, Maxim A. Makeev

Mechanical and Materials Engineering Faculty Publications

The time evolution of the pore size distributions and mechanical properties of amorphous solids at constant pressure is studied using molecular dynamics simulations. The porous glasses were initially prepared at constant volume conditions via a rapid thermal quench from the liquid state to the glassy region and allowing for simultaneous phase separation and material solidification. We found that at constant pressure and low temperature, the porous network becomes more compact and the glassy systems relocate to progressively lower levels of the potential energy. Although the elastic modulus and the average glass density both increase with the waiting time, their dependence …