Mechanical Engineering Commons^™

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 …

Good Similar Patches For Image Denoising (Poster), Si Lu

Computer Science Faculty Publications and Presentations

Patch-based denoising algorithms like BM3D have achieved outstanding performance. An important idea for the success of these methods is to exploit the recurrence of similar patches in an input image to estimate the underlying image structures....

Multi-Scale Modeling Of Viscoelastic Thin-Ply Composites, Milinda Madhusanka Yapa Yapa Hamillage

Electronic Theses and Dissertations

Thin ply composites have been under the microscope of researchers for around two decades since Kawabe introduced the thin ply technology, in the Industrial Technology Center in Fukui, Japan. With the advancement of the technological aspects of manufacturing carbon fiber composites the tow spreading has improved so much as to reduce the thickness of a conventional ply up to even six-fold. Over the years carbon fiber composites have gained interest in space structures for reinforcement purposes in antennas, as structural elements that store strain energy and support the deployment of deployable structures, and in reflector concepts. Now thin-ply composites are …

Design Rules For Additive Manufacturing – Understanding The Fundamental Thermal Phenomena To Reduce Scrap, M. Reza Yavari, Kevin D. Cole, Prahalada K. Rao

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this work is to predict the effect of part geometry and process parameters on the direction and magnitude of heat flow heat flux in parts made using metal additive manufacturing (AM) processes. As a step towards this goal, the objective of this paper is to develop and apply the mathematical concept of heat diffusion over graphs to approximate the heat flux in metal AM parts as a function of their geometry. This objective is consequential to overcome the poor process consistency and part quality in AM. Currently, part build failure rates in metal AM often exceed 20%, …

Metabolic Cost Calculations Of Gait Using Musculoskeletal Energy Models, A Comparison Study, Anne D. Koelewijn, Dieter Heinrich, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

This paper compares predictions of metabolic energy expenditure in gait using seven metabolic energy expenditure models to assess their correlation with experimental data. Ground reaction forces, marker data, and pulmonary gas exchange data were recorded for six walking trials at combinations of two speeds, 0.8 m/s and 1.3 m/s, and three inclines, -8% (downhill), level, and 8% (uphill). The metabolic cost, calculated with the metabolic energy models was compared to the metabolic cost from the pulmonary gas exchange rates. A repeated measures correlation showed that all models correlated well with experimental data, with correlations of at least 0.9. The model …

Controlled Bubble Dynamics Inside Micropillar Arrays, Faraz Khalil Arya

Electronic Theses and Dissertations

Bubble dynamics inside micro domains was manipulated and used to pump liquid. Micropillars were formed inside two 1.5 mm wide and 220 µm high microchannels with a length of 23 mm. One microchannel had three arrays of micropillars with diameters of 40 µm and the other had a single array of micropillars with diameters of 30 µm. An array of five 200 µm by 200 µm heaters was deposited inside these micropillar arrays and was used to control bubble size and trajectory. A sequential power switching of the heaters was used to pump liquid in a desired direction with a …

Improving Turbine Performance: A Contribution To The Understanding Of Heat Transfer And Vortical Structures In Staggered Pin Fin Arrays, Marcel Otto

Electronic Theses and Dissertations

Through the comparison of flow structures, velocity contours, turbulence statistics, and additional flow quantities, the error sources of RANS are qualitatively described. The findings in this work will help gas turbine design engineers to tweak their turbulence models and give guidance on the interpretation of their results. The novelty is the application of the transient TLC method on this type of geometry as well as the near-wall PIV measurements. The advancements in additive manufacturing disrupt the classic turbine cooling development for casted airfoils. More and more complicated shapes and cooling schemes are possible. Nonetheless, a detailed physical understanding of fundamental …

A Theoretical, Numerical, And Experimental Study Of Trapped Droplet Coalescence And Mixing, Passively And Under Electric Field, Alireza Karbalaei Baba

Electronic Theses and Dissertations

Passive and electrically active coalescence and mixing of pairs of trapped squeezed nanodroplets were studied in this work. PDMS-glass microfluidic devices were designed and fabricated using multilevel photolithography technique. Flow-focusing method was used to generate nanoliter droplets of died glycerol inside oleic acid. The effect of factors such as flow rates and their ratio, interfacial tension, and viscosities on the size and frequency of droplet generation was studied and concluded by demonstrating the capillary number effect. A passive droplet trapping technique based on minimizing the surface energy of the droplets was employed to minimize the shear flow effects and increase …

Compressible Turbulent Reactions For Hypersonic Propulsion Applications, Jonathan Sosa

Electronic Theses and Dissertations

This work presents the first measurement of turbulent burning velocities of a highly-turbulent compressible standing flame induced by shock-driven turbulence in a Turbulent Shock Tube. High-speed schlieren, chemiluminescence, PIV, and dynamic pressure measurements are made to quantify flame-turbulence interaction for high levels of turbulence at elevated temperatures and pressure. Distributions of turbulent velocities, vorticity and turbulent strain are provided for regions ahead and behind the standing flame. The turbulent flame speed is directly measured for the high-Mach standing turbulent flame. From measurements of the flame turbulent speed and turbulent Mach number, transition into a non-linear compressibility regime at turbulent Mach …

Shock Tube Investigations Of Novel Combustion Environments Towards A Carbon-Neutral Future, Samuel Barak

Electronic Theses and Dissertations

Supercritical carbon dioxide (sCO2) cycles are being investigated for the future of power generation. These cycles will contribute to a carbon-neutral future to combat the effects of climate change. These direct-fired closed cycles will produce power without adding significant pollutants to the atmosphere. For these cycles to be efficient, they will need to operate at significantly higher pressures (e.g., 300 atm for Allam Cycle) than existing systems (typically less than 40 atm). There is limited knowledge on combustion at these pressures or at the high dilution of carbon dioxide. Nominal fuel choices for gas turbines include natural gas and syngas …