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Dynamic Fracture At An Interface: A Peridynamic Analysis, Javad Mehrmashhadi, Longzhen Wang, Quang Van Le, Florin Bobaru Ph.D. Nov 2018

Dynamic Fracture At An Interface: A Peridynamic Analysis, Javad Mehrmashhadi, Longzhen Wang, Quang Van Le, Florin Bobaru Ph.D.

Javad Mehrmashhadi

Recent impact experiments showed the influence a strong or weak interface in a bi-layered PMMA material has on dynamic fracture mechanisms. We show that a linear elastic with brittle damage peridynamic model, which works very well for glass, leads to crack propagation speeds significantly faster than those measured experimentally in the PMMA system. We propose an explanation for this behavior: localized heating in the region near the crack tip (due to high strain rates) softens the material sufficiently to make a difference. We introduce this effect in our peridynamic model, via a bi-linear bond force-strain relationship, and the computed crack ...


Dynamic Fracture Of Pmma, Intefacial Failure, And Local Heating, Javad Mehrmashhadi, Longzhen Wang, Florin Bobaru Ph.D. Nov 2018

Dynamic Fracture Of Pmma, Intefacial Failure, And Local Heating, Javad Mehrmashhadi, Longzhen Wang, Florin Bobaru Ph.D.

Javad Mehrmashhadi

Recent impact experiments showed the influence of a strong or weak interface in a bi-layered PMMA material has on dynamic fracture mechanisms. We show that a linear elastic with brittle damage peridynamic model, which works very well for glass, leads to crack propagation speeds significantly faster than those measured experimentally in the PMMA system. We propose an explanation for this behavior: localized heating in the region near the crack tip (due to high strain rates) softens the material sufficiently to make a difference. We introduce this effect in our peridynamic model, via a bi-linear bond force-strain relationship, and the computed ...


The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2018, Buenaventura "Ven" Basco Oct 2018

The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2018, Buenaventura "Ven" Basco

Buenaventura "Ven" Basco

No abstract provided.


The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2017, Buenaventura "Ven" Basco Oct 2018

The Subject Librarian Newsletter, Engineering And Computer Science, Fall 2017, Buenaventura "Ven" Basco

Buenaventura "Ven" Basco

No abstract provided.


Multi-Objective Bayesian Optimization Of Super Hydrophobic Coatings On Asphalt Concrete Surfaces, Ali Nahvi, Ali Arabzadeh, Alireza Sassani, Mohammadkazem Sadoughi, Halil Ceylan Aug 2018

Multi-Objective Bayesian Optimization Of Super Hydrophobic Coatings On Asphalt Concrete Surfaces, Ali Nahvi, Ali Arabzadeh, Alireza Sassani, Mohammadkazem Sadoughi, Halil Ceylan

Ali Nahvi

Conventional snow removal strategies add direct and indirect expenses to the economy through profit lost due to passenger delays costs, pavement durability issues, contaminating the water runoff, and so on. The use of superhydrophobic (super-water-repellent) coating methods is an alternative to conventional snow and ice removal practices for alleviating snow removal operations issues. As an integrated experimental and analytical study, this work focused on optimizing superhydrophobicity and skid resistance of hydrophobic coatings on asphalt concrete surfaces. A layer-by-layer (LBL) method was utilized for spray depositing polytetrafluoroethylene (PTFE) on an asphalt concrete at different spray times and variable dosages of PTFE ...


Gnygrens18.Pdf, Garrett Nygren Aug 2018

Gnygrens18.Pdf, Garrett Nygren

Garrett Nygren

The finite element method was used to evaluate microstructural strengthening and toughening effects in nanoparticulate reinforced polymer composites (nanocomposites) and in short aligned discontinuous fiber reinforced polymer composites. Nanoparticulate reinforcement is a well-known method of polymer toughening which can greatly expand the range of engineering applications for polymers. However, the mechanisms of nanoparticulate toughening, as well as complementary sub-micron fracture processes, are not well understood. Short, aligned, discontinuous carbon fiber reinforced thermoplastics show promise as a versatile, inexpensive material system with favorable manufacturability, but failure of the associated morphologies is also not yet well explored.
In nanocomposites, two microstructural effects ...


2018-19 Tla Application - Thermal Fluid Sequence, M. A. Rafe Biswas Jul 2018

2018-19 Tla Application - Thermal Fluid Sequence, M. A. Rafe Biswas

M. A. Rafe Biswas

No abstract provided.


Advances In Composite Manufacturing Of Helicopter Parts, Tobias A. Weber, Hans-Joachim K. Ruff-Stahl Jul 2018

Advances In Composite Manufacturing Of Helicopter Parts, Tobias A. Weber, Hans-Joachim K. Ruff-Stahl

Hans-Joachim Ruff-Stahl

This study investigates and compares different methods for improving standard autoclave composite manufacturing in order to find suitable approaches to a more efficient composite production. The goal is not only a reduction in manufacturing times and costs but also quality enhancement. Improved part quality while decreasing costs enables a manufacturer of composite parts to expand its market share, especially in the helicopter market, which has been constantly shrinking over the last two years. Various approaches such as improved tooling technology, the use of automated systems for lamination as well as outsourcing are examined to provide an overview of possible advancements ...


Agonabadietal_2018_Eduexoemgdelaytutorial_13.Pdf, Arash Mohammadzadeh Gonabadi, Philippe Malcolm Jul 2018

Agonabadietal_2018_Eduexoemgdelaytutorial_13.Pdf, Arash Mohammadzadeh Gonabadi, Philippe Malcolm

Philippe Malcolm

No abstract provided.


Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi Jul 2018

Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi

Nima Fathi

Horizontal linear shear stress apparatus offers a convenient way to study the rheology of rigid particles suspended in viscous shear flows in the laboratory. The single particle trajectories of a buoyant spherical solid particle in a linear shear flow are investigated. Reynolds numbers less than 0.1 are considered to provide the creeping flow in this investigating. The experimental apparatus provides a linear stress, Stokes, Couette flow where the wall boundary conditions of the set up can change. The two-dimensional CFD analysis is performed to simulate the primary and secondary phases of the domain. Our numerical assessment, discrete phase element ...


Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee Jul 2018

Dynamical Thermal Conductivity Of Suspended Graphene Ribbons In The Hydrodynamic Regime, Zlatan Aksamija, Arnab K. Majee

Zlatan Aksamija

The steady-state behavior of thermal transport in bulk and nanostructured semiconductors has been widely
studied, both theoretically and experimentally. On the other hand, fast transients and frequency dynamics of
thermal conduction has been given less attention. The frequency response of thermal conductivity has become
more crucial in recent years, especially in light of the constant rise in the clock frequencies in microprocessors
and terahertz sensing applications. Thermal conductivity in response to a time-varying temperature field starts
decaying when the frequency exceeds a cutoff frequency Omega_c, which is related to the inverse of phonon relaxation time τ, on the order of ...


Real-Time Simulation Of Three-Dimensional Shoulder Girdle And Arm Dynamics, Edward K. Chadwick, Dimitra Blana, Robert F. Kirsch, Antonie J. Van Den Bogert May 2018

Real-Time Simulation Of Three-Dimensional Shoulder Girdle And Arm Dynamics, Edward K. Chadwick, Dimitra Blana, Robert F. Kirsch, Antonie J. Van Den Bogert

Antonie J. van den Bogert

Electrical stimulation is a promising technology for the restoration of arm function in paralyzed individuals. Control of the paralyzed arm under electrical stimulation, however, is a challenging problem that requires advanced controllers and command interfaces for the user. A real-time model describing the complex dynamics of the arm would allow user-in-the-loop type experiments where the command interface and controller could be assessed. Real-time models of the arm previously described have not included the ability tomodel the independently controlled scapula and clavicle, limiting their utility for clinical applications of this nature. The goal of this study therefore was to evaluate the ...


Semiactive Virtual Control Method For Robots With Regenerative Energy-Storing Joints, Hanz Richter, Daniel J. Simon, Antonie J. Van Den Bogert May 2018

Semiactive Virtual Control Method For Robots With Regenerative Energy-Storing Joints, Hanz Richter, Daniel J. Simon, Antonie J. Van Den Bogert

Antonie J. van den Bogert

A framework for modeling and control is introduced for robotic manipulators with a number of energetically self-contained semiactive joints. The control approach consists of three steps. First, a virtual control design is conducted by any suitable means, assuming a fully-actuated system. Then, virtual control inputs are matched by a parameter modulation law. Finally, the storage dynamics are shaped using design parameters. Storage dynamics coincide with the system's internal dynamics under exact virtual control matching. An internal energy balance equation and associated self-powered operation condition are given for the semiactive joints. This condition is a structural characteristic of the system ...


Relationship Between Jump Landing Kinematics And Peak Acl Force During A Jump In Downhill Skiing: A Simulation Study, D. Heinrich, Antonie J. Van Den Bogert, W. Nachbauer May 2018

Relationship Between Jump Landing Kinematics And Peak Acl Force During A Jump In Downhill Skiing: A Simulation Study, D. Heinrich, Antonie J. Van Den Bogert, W. Nachbauer

Antonie J. van den Bogert

Recent data highlight that competitive skiers face a high risk of injuries especially during off-balance jump landing maneuvers in downhill skiing. The purpose of the present study was to develop a musculo-skeletal modeling and simulation approach to investigate the cause-and-effect relationship between a perturbed landing position, i.e., joint angles and trunk orientation, and the peak force in the anterior cruciate ligament (ACL) during jump landing. A two-dimensional musculo-skeletal model was developed and a baseline simulation was obtained reproducing measurement data of a reference landing movement. Based on the baseline simulation, a series of perturbed landing simulations (n=1000) was ...


An Elaborate Data Set On Human Gait And The Effect Of Mechanical Perturbations, Jason K. Moore, Sandra K. Hnat, Antonie J. Van Den Bogert May 2018

An Elaborate Data Set On Human Gait And The Effect Of Mechanical Perturbations, Jason K. Moore, Sandra K. Hnat, Antonie J. Van Den Bogert

Antonie J. van den Bogert

Here we share a rich gait data set collected from fifteen subjects walking at three speeds on an instrumented treadmill. Each trial consists of 120 s of normal walking and 480 s of walking while being longitudinally perturbed during each stance phase with pseudo-random fluctuations in the speed of the treadmill belt. A total of approximately 1.5 h of normal walking (>5000 gait cycles) and 6 h of perturbed walking (>20,000 gait cycles) is included in the data set. We provide full body marker trajectories and ground reaction loads in addition to a presentation of processed data that ...


The Subject Librarian Newsletter, Nanoscience, Fall 2016, Sandy Avila Apr 2018

The Subject Librarian Newsletter, Nanoscience, Fall 2016, Sandy Avila

Sandy Avila

No abstract provided.


Extracting Vibration Characteristics Of A Guitar Using Finite Element, Modal Analysis, And Digital Image Correlation Techniques, Kiran Patil, Javad Baqersad, Daniel Ludwigsen, Yaomin Dong Apr 2018

Extracting Vibration Characteristics Of A Guitar Using Finite Element, Modal Analysis, And Digital Image Correlation Techniques, Kiran Patil, Javad Baqersad, Daniel Ludwigsen, Yaomin Dong

Daniel Ludwigsen

The sound quality generated by the guitar depends on the vibration characteristics (i.e. natural frequencies and mode shapes) of this instrument. Thus, it is of particular interest to the guitar manufacturers to be able to obtain global information about the characteristics of the guitar. Traditional sensors can only measure at discrete locations. However, digital image correlation (DIC) can measure full-field data on the surface of the structure. In the current paper, a finite element (FE) model of a guitar with free boundary configurations was developed using quadratic solid elements. An eigensolution was performed on the FE model to determine ...


Three Hundred And Sixty Degree Real-Time Monitoring Of 3-D Printing Using Computer Analysis Of Two Camera Views, Siranee Nuchitprasitchai, Michael C. Roggeman, Joshua M. Pearce Mar 2018

Three Hundred And Sixty Degree Real-Time Monitoring Of 3-D Printing Using Computer Analysis Of Two Camera Views, Siranee Nuchitprasitchai, Michael C. Roggeman, Joshua M. Pearce

Joshua M. Pearce

Prosumer (producing consumer)-based desktop additive manufacturing has been enabled by the recent radical reduction in 3-D printer capital costs created by the open-source release of the self-replicating rapid prototype (RepRap). To continue this success, there have been some efforts to improve reliability, which are either too expensive or lacked automation. A promising method to improve reliability is to use computer vision, although the success rates are still too low for widespread use. To overcome these challenges an open source low-cost reliable real-time optimal monitoring platform for 3-D printing from double cameras is presented here. This error detection system is ...


Distributed Manufacturing Of Flexible Products: Technical Feasibility And Economic Viability, Aubrey Woern, Joshua M. Pearce Mar 2018

Distributed Manufacturing Of Flexible Products: Technical Feasibility And Economic Viability, Aubrey Woern, Joshua M. Pearce

Joshua M. Pearce

Distributed manufacturing even at the household level is now well established with the combined use of open source designs and self-replicating rapid prototyper (RepRap) 3-D printers. Previous work has shown substantial economic consumer benefits for producing their own polymer products. Now flexible filaments are available at roughly 3-times the cost of more conventional 3-D printing materials. To provide some insight into the potential for flexible filament to be both technically feasible and economically viable for distributed digital manufacturing at the consumer level this study investigates 20 common flexible household products. The 3-D printed products were quantified by print time, electrical ...


Free And Open Source 3-D Model Customizer For Websites To Democratize Design With Openscad, Yuenyong Nilsiam, Joshua M. Pearce Mar 2018

Free And Open Source 3-D Model Customizer For Websites To Democratize Design With Openscad, Yuenyong Nilsiam, Joshua M. Pearce

Joshua M. Pearce

3-D printing has entered the consumer market because of recent radical price declines. Consumers can save substantial money by offsetting purchases with DIY pre-designed 3-D printed products. However, even more value can be obtained with distributed manufacturing using mass customization. Unfortunately, the average consumer is not technically sophisticated enough to easily design their own products. One solution to this is the use of an overlay on OpenSCAD parametric code, although current solutions force users to relinquish all rights to their own designs. There is thus a substantial need in the open source design community for a libre 3-D model customizer ...


Energy Payback Time Of A Solar Photovoltaic Powered Waste Plastic Recyclebot System, Shan Zhong, Pratiksha Rakhe, Joshua M. Pearce Mar 2018

Energy Payback Time Of A Solar Photovoltaic Powered Waste Plastic Recyclebot System, Shan Zhong, Pratiksha Rakhe, Joshua M. Pearce

Joshua M. Pearce

The growth of both plastic consumption and prosumer 3-D printing are driving an interest in producing 3-D printer filaments from waste plastic. This study quantifies the embodied energy of a vertical DC solar photovoltaic (PV) powered recyclebot based on life cycle energy analysis and compares it to horizontal AC recyclebots, conventional recycling, and the production of a virgin 3-D printer filament. The energy payback time (EPBT) is calculated using the embodied energy of the materials making up the recyclebot itself and is found to be about five days for the extrusion of a poly lactic acid (PLA) filament or 2 ...


Open Source Multi-Head 3d Printer For Polymer-Metal Composite Component Manufacturing, J. Laureto, Joshua M. Pearce Mar 2018

Open Source Multi-Head 3d Printer For Polymer-Metal Composite Component Manufacturing, J. Laureto, Joshua M. Pearce

Joshua M. Pearce

As low-cost desktop 3D printing is now dominated by free and open source self-replicating rapid prototype (RepRap) derivatives, there is an intense interest in extending the scope of potential applications to manufacturing. This study describes a manufacturing technology that enables a constrained set of polymer-metal composite components. This paper provides (1) free and open source hardware and (2) software for printing systems that achieves metal wire embedment into a polymer matrix 3D-printed part via a novel weaving and wrapping method using (3) OpenSCAD and parametric coding for customized g-code commands. Composite parts are evaluated from the technical viability of manufacturing ...


Impact Of Diy Home Manufacturing With 3d Printing On The Toy And Game Market, Emily Peterson, Joshua M. Pearce Mar 2018

Impact Of Diy Home Manufacturing With 3d Printing On The Toy And Game Market, Emily Peterson, Joshua M. Pearce

Joshua M. Pearce

The 2020 toy and game market is projected to be US$135 billion. To determine if 3D printing could affect these markets if consumers offset purchases by 3D printing free designs, this study investigates the 100 most popular downloaded designs at MyMiniFactory in a month. Savings are quantified for using a Lulzbot Mini 3D printer and three filament types: commercial filament, pellet-extruded filament, and post-consumer waste converted to filament with a recyclebot. Case studies probed the quality of: (1) six common complex toys; (2) Lego blocks; and (3) the customizability of open source board games. All filaments analyzed saved the ...


Open Source 3-D Printed Nutating Mixer, Dhwani K. Trivedi, Joshua M. Pearce Mar 2018

Open Source 3-D Printed Nutating Mixer, Dhwani K. Trivedi, Joshua M. Pearce

Joshua M. Pearce

As the open source development of additive manufacturing has led to low-cost desktop three-dimensional (3-D) printing, a number of scientists throughout the world have begun to share digital designs of free and open source scientific hardware. Open source scientific hardware enables custom experimentation, laboratory control, rapid upgrading, transparent maintenance, and lower costs in general. To aid in this trend, this study describes the development, design, assembly, and operation of a 3-D printable open source desktop nutating mixer, which provides a fixed 20° platform tilt angle for a gentle three-dimensional (gyrating) agitation of chemical or biological samples (e.g., DNA or ...


Evaluation And Enhancement Of Solar Chimney Power Plant, Nima Fathi Mar 2018

Evaluation And Enhancement Of Solar Chimney Power Plant, Nima Fathi

Nima Fathi

Clean (and specifically renewable) energy is steadily improving its global share. However, finite availability of fossil fuels and the growing effects of climate change make it an urgent priority to convince the industry and governments to incentivize investment in the renewable energy field and to make it more attractive by decreasing the capital cost. Until recently, uncertainties in funding limited renewable energy development, especially in the US. That limitation has been one of the barriers to progress. Another limitation of many renewable energy systems is the variability in their output, which makes them unsuitable for baseline power production. Therefore, fossil ...


Quantitative Understanding Of Nanoparticle Flocculation In Water Treatment, Sungmin Youn Mar 2018

Quantitative Understanding Of Nanoparticle Flocculation In Water Treatment, Sungmin Youn

Sungmin Youn

Flocculation is critical in drinking water treatment; in flocculation, the particle size distribution changes from a large number of small particles to a small number of larger particles. Larger particles are effectively removed by settling and filtration processes that follow flocculation. In recent years, manufacturing of engineered nanoparticles has skyrocketed, and these nanoparticles can enter our water supplies, but knowledge of their fate in water treatment is limited. The objective of this research was to update knowledge of flocculation by extending previous work at the microscale to the nanoscale.

Flocculation involves transport of particles to the vicinity of one another ...


Crack Growth Induced By Sonic Ir Inspection, John C. Chen, Jacob Kephart, Kyle Lick, William T. Riddell Feb 2018

Crack Growth Induced By Sonic Ir Inspection, John C. Chen, Jacob Kephart, Kyle Lick, William T. Riddell

William Riddell

We have developed an experiment to study the propagation of laboratory-synthesized fatigue cracks under various controlled conditions during Sonic IR inspection. The experiment provides for good repeatability in testing. The parameters of interest include the initial crack length, load history (stress intensity and load ratio) during crack generation, geometry of the crack, material and also the various conditions involving the ultrasonic excitation source. In general, we find that under typical sonic IR inspection conditions, the initial crack will propagate under sonic IR testing. The crack growth after each inspection event varies and exhibits a distribution in length of propagation. The ...


Sure Abstract - Spring 2018: Analysis And Application Of Biomimetic Metamaterial Scales, Ryan Horton Feb 2018

Sure Abstract - Spring 2018: Analysis And Application Of Biomimetic Metamaterial Scales, Ryan Horton

Ryan Horton

No abstract provided.


Effects Of Repetitive Pulsing On Multi-Khz Planar Laser-Induced Incandescence Imaging In Laminar And Turbulent Flames, James Bennett Michael, Prabhakar Venkateswaran, Christopher R. Shaddix, Terrence R. Meyer Jan 2018

Effects Of Repetitive Pulsing On Multi-Khz Planar Laser-Induced Incandescence Imaging In Laminar And Turbulent Flames, James Bennett Michael, Prabhakar Venkateswaran, Christopher R. Shaddix, Terrence R. Meyer

James Michael

Planar laser-induced incandescence (LII) imaging is reported at repetition rates up to 100 kHz using a burst-mode laser system to enable studies of soot formation dynamics in highly turbulent flames. To quantify the accuracy and uncertainty of relative soot volume fraction measurements, the temporal evolution of the LII field in laminar and turbulent flames is examined at various laser operating conditions. Under high-speed repetitive probing, it is found that LII signals are sensitive to changes in soot physical characteristics when operating at high laser fluences within the soot vaporization regime. For these laser conditions, strong planar LII signals are observed ...