Mechanical Engineering

Mechanical Engineering

 

 

Poster Number: ME-01

Authors: Fatemeh Afzali, Brian F. Feeny

Title:  Vibrational Analysis of Vertical Axis Wind Turbine Blades Containing Time Varying Damping Coefficient

 

Abstract: The derivation of a vibration model for an H-rotor/Giromill blade is investigated. The blade is treated as a uniform straight elastic Euler-Bernoulli beam under transverse bending and twisting deformation. The derivation of the energy equations for the bending and twisting blade and a simplified aerodynamic model is issued. Lagrange's equations are applied to assumed modal coordinates to obtain nonlinear equations of motion for bend and twist. A single quasi-steady airfoil theory is applied to obtain the aeroelastic loads. The behavior of the linearized equation for bend only is examined.

We study the response of a linear differential equation, for an oscillator for which the damping coefficient varies periodically in time.

We use Floquet theory combined with the harmonic balance method to find the approximate solution and capture the stability criteria. Based on Floquet theory the approximate solution includes the exponential part having an unknown exponent, and a periodic part, which is expressed using a truncated series of harmonics. After substituting the assumed response in the equation, the harmonic balance method is applied. We use the characteristic equation of the truncated harmonic series to obtain the Floquet exponents. Eventually, the stability and the response of the damped system for a set of parameters are shown.

 

 

 

Poster Number: ME-02

Authors: Ali Al-Hajjar, Ali Al-Jiboory, Shan Min Swei, Guoming George Zhu

Title:  Aircraft Flutter Suppression

 

Abstract: Aircraft flutter is a dangerous and catastrophic instability phenomena which results as the interaction between the structural dynamics and aerodynamics. This interaction will cause unstable oscillation and failure. There are many methods used to suppress this phenomena. Some methods suggests to fortify the aircraft structure, but this will increase the mass of the aircraft which is strongly undesirable in the aerospace applications. The active flutter suppression is the best way to suppress the flutter without increasing the mass of the aircraft. In this work we do an active flutter suppression to aircraft, which effectively enhance the stability and performance of the aircraft.

 

 

 

Poster Number: ME-03

Authors: Sheng Chen, Sara Roccabianca

Title:  Effect of Storage Condition, Orientation, Location and Gender on Rat Back Skin Mechanical Properties

 

Abstract: The determination of biomechanical properties of soft tissues like skin involves mechanical tensile test. In practice, skin samples cannot always be tested right after removal from the subjects. The purpose of this work is to determine the storage protocol that preserves skin mechanical properties the most by evaluating mechanical characteristics on five parameters: initial slope, maximum slope, rupture strain, ultimate tensile strength (UTS), and toughness. Also, the differences due to orientation, location and gender are studied in this work. Sixteen Sprague Dawley rats, eight males and eight females, aged between 10 to 12 weeks were used in the study. Skin samples from rat back skin went through quasi-static uniaxial tensile test. ANOVA results show that there are no statistically significant (5%) differences between four storage protocols on five evaluated parameters, while Protocol III (flash frozen at -78.5°C, stored at -80°C, and thawed at 4°C for 6h before testing) is the one that preserves the stress-stretch curve characteristics the most in both cyclic loading and rupture loading curves, compared with the control group Protocol I. The study reports no differences between male and female animals, but statistically significant differences on orientation and location. This work is valuable for people who need a proper protocol to store their soft tissue samples for further mechanical tensile test.

 

 

 


 

Poster Number: ME-04

Authors: Amber R. Cussen, Gail A. Shafer, Tamara R. Bush

Title:  Device Design and Development to Measure Carpometacarpal Joint Force Application: Preliminary Results

 

Abstract: Osteoarthritis (OA) of the carpometacarpal (CMC) joint is a debilitating and prevalent disease affecting nearly 50% of U.S. adults over 55. While OA of the CMC joint is characterized by waning grip strength, minimal research has investigated the individual thumb muscle actions that correlate to this reduced function and no device is currently capable of measuring the applied force of the CMC joint during thumb motion. In this study, we built a thumb CMC joint apparatus that attaches to a multi-axis load. The device is capable of measuring forces applied during flexion (palmar abduction), extension, (radial) abduction, and adduction. Our goals for device design included: 1) adjustable to accommodate varying hand size, 2) hand placement is consistent and measures are repeatable, 3) isolates CMC joint action, 4) can detect force magnitude and direction, and 5) is durable to accommodate numerous patients. To meet these objectives, a palmar hand support and a connected structure that allowed for mounting of the load cell were machined out of aluminum. Both pieces are adjustable to accommodate varying hand sizes. Thumb forces are applied to a customized circular ring connected to the load cell to allow for symmetrical thumb movements and bilateral testing. This portable apparatus is designed to be placed on an adjustable table top and is designed to be used with a standard adjustable office chair. Each CMC joint action can be measured independently. Pilot testing suggests that our apparatus can be used with both OA and asymptomatic subjects.

 

 

 

 

Poster Number: ME-05

Authors: Amber R. Cussen, Tony Trier, Laura Bix, Tamara R. Bush

Title:  Development of a Methodology to Evaluate the Biomechanics Associated with Aseptic Presentation of Sterile Medical Pouches

 

Abstract: Hospital-acquired infections (HAIs) are a significant cause of in-patient morbidity and mortality. Although many contributors to HAIs are carefully surveilled, sterile package opening and guideline compliance evaluations are lacking. Additionally, only a portion of aseptic presentation guidelines are evidence-based. In this pilot study, we developed a method using motion capture to evaluate the movements associated with aseptic package opening. Nine health professionals trained in sterile package opening and scrub procedures were recruited to open two chevron-style package sizes while wearing 13 reflective markers to detect movement. Participant movement was then evaluated for compliance to aseptic presentation guidelines. No participant was able to present both packages of either size without crossing the sterile field. When opening large sized packages, participants pulled open to a greater degree (larger pull distance), performed more repetitive motions and spent more time handling the packages. In this study, we show motion capture methods are sufficient to detect human factors associated with aseptic package guideline compliance, and participants have more difficulty abiding to best practice guidelines when opening large sized packages. Our methodology can be used to identify handling behaviors that depart from established guidelines. In combination with contamination data collection, our method can also be used to relate specific handling behaviors to contamination risk, thus providing healthcare providers with an evidence basis for training and improved opening techniques.

 

 

 

Poster Number: ME-06

Authors: Joshua Drost, Tamara R. Bush

Title:  Modeling Changes to Force and Function of the Hand Due to Osteoarthritis

 

Abstract: Currently, the methods used to assess functional changes in hand function are primarily surveys, pain scales and radiological exams which are all subjective. A model that maps both the force and motion abilities will allow clinicians to objectively compare changes in hand function throughout rehabilitation and treatment. Recently, we modeled the changes in the range of motions of the hand caused by arthritis. The goal of this work was to determine forces associated with the index finger and create a predictive model of the force abilities of participants over their range of motion for participants with and without reduced hand functionality. Sixteen “Healthy” participants and fifteen “Arthritic” participants were included in this study. Maximum forces were measured in nineteen trials over the range of motion. After collection, the data were analyzed in terms of the position (x,y,z coordinate), direction and magnitude of the force applied. A linear mixed effect model was used to create predict to full force abilities for the healthy and arthritic participants. Future work will include the measurement of forces for all fingers and for a larger subject group. Clinically, this model is highly innovative and useful: measures of motion and force will be gathered for individuals to assess the difference as compared to an average healthy individual. Also the individual can be measured multiple times throughout treatment to track improvement to hand function.

Poster Number: ME-07

Authors: Masumeh Gholamisheeri, Elisa Toulson

Title:  Experiments and CFD Modeling of a Homogeneously Charged Turbulent Jet Ignition (TJI) System

 

Abstract: Advanced ignition systems can be effective approaches to reduce NOx emissions and improve efficiency in automotive applications. Prechamber ignition systems such as the Turbulent Jet Ignition (TJI) system are modern technologies that improve engine efficiency while lowering fuel consumption through low temperature combustion. TJI enables fast burn rates that allow for increased levels of dilution and lean burn combustion. In the presented research, transient jet ignition of a homogeneous methane air mixture in a TJI system is studied computationally using Large Eddy Simulation (LES) and Reynolds averaged Navier-Stokes (RANS) turbulent models. In TJI a turbulent jet discharges from a prechamber into the main chamber via one/multiple orifice(s) and provides a distributed ignition source. The effect of orifice size and stoichiometry is studied through simulations performed with the Converge CFD code. A reduced chemical kinetic mechanism is used for combustion modeling along with a zero-equation Smagorinsky sub-model and RNG k-ε model for turbulence modeling. The computed pressure traces are compared with experimental data measured in the Rapid Compression Machine (RCM) experimental tests. The comparison indicates that the CFD results are in acceptable agreement with the experimental data during compression and the early stage of combustion, however, an over-prediction of peak pressure was reported. Pressure traces are scaled and CFD temperature contours for various nozzle orifices and air-fuel ratios are compared in order to achieve deeper insight into the TJI combustion process in the RCM combustion cylinder.

 

This work was supported in part by NSF-DOE

 

 

 

Poster Number: ME-08

Authors: Jun Guo, Rigoberto Burgueño

Title:  Tailoring the Elastic Postbuckling Response of Cylindrical Shells under Axial Compression

 

Abstract: Buckling has traditionally been considered as a failure limit and thus a condition to avoid, but recently it has been recognized as a promising response phenomenon to design smart applications, such as energy harvesting, frequency tuning, sensing, actuation, etc. Cylindrical shells are considered a good prototype for smart applications since they have advantages over other structural forms in their ability to attain multiple buckling events in their elastic postbuckling response. Yet, to design smart applications from cylindrical shells requires that their elastic postbuckling response be controllable, tailored and be relatively less sensitive to imperfections. The postbuckling behavior of axially-compressed cylindrical shells with a uniform stiffness distribution has been extensively studied. Conversely, the response of cylindrical shells with non-uniform stiffness distribution, mainly used to increase their load-carrying capacity, has caught little attention. The study presented here shows, through numerical simulations and experiments, that the design of varied stiffness distributions on the surface of axially-compressed shells can tailor their elastic postbuckling response. The shell surface was discretized into cells and some of them were thickened with respect to the baseline uniform shell thickness. By introducing the non-uniform thickness distribution, the number, sequence, and location of local buckling events in the far elastic post-buckling response can be tailored. In addition, the shell’s elastic postbuckling response type (i.e., softening, sustaining of stiffening) can be controlled and is expected to show reduced sensitivity to random initial imperfections.

 

 

 

Poster Number: ME-09

Authors: Patrick Hammer, Ahmed Naguib, Manoochehr Koochesfahani

Title:  Lift on a Low Reynolds Number Steady Airfoil in Uniform Shear Flow

 

Abstract: Two-dimensional computations have been performed on a steady NACA 0012 airfoil at zero angle of attack and chord Reynolds number of 12,000 in a uniform-shear approach flow. It is found that the average lift coefficient has an opposite sign to the inviscid solution for the same airfoil, while having a lower magnitude. It is hypothesized that this different sign of lift is caused by a slight camber towards the low-speed side of effective shape of the airfoil, created by asymmetry in the boundary layer displacement thickness. Analysis of the computed flow pattern around the airfoil supports this hypothesis.

 

This work was supported in part by AFOSR grant number FA9550-15-1-0224

 


 

Poster Number: ME-10

Authors: Tianyi He, Ali Khudhair Al-Jiboory, Sean Shan-Min Swei, Guoming G. Zhu

Title:  Switching State-feedback LPV Control with Uncertain Scheduling Parameters

 

Abstract: This paper presents a new method to design Robust Switching State-Feedback Gain-Scheduling (RSSFGS) controllers for Linear Parameter Varying (LPV) systems with uncertain scheduling parameters. The domain of scheduling parameters are divided into several overlapped subregions to undergo hysteresis switching among a family of simultaneously designed LPV controllers over the corresponding subregion with the guaranteed $\mathcal{H}_{\infty}$ performance. The synthesis conditions are given in terms of Parameterized Linear Matrix Inequalities that guarantee both stability and performance at each subregion and associated switching surfaces. The switching stability is ensured by descent parameter-dependent Lyapunov function on switching surfaces. By solving the optimization problem, RSSFGS controller can be obtained for each subregion. A numerical example is given to illustrate the effectiveness of the proposed approach over the non-switching controllers.

 

This work was supported in part by NASA ARMD Convergent Aeronautics Solutions (CAS) Project

 

 

 

Poster Number: ME-11

Authors: Alexander Ho, Alborz Izadi, Rebecca Anthony

Title:  Conformal Deposition of Nanocrystals onto Surfaces

 

Abstract: Nanocrystals can be incorporated into a variety of applications due to their tunable optical and electronic properties. There are various applications that require structures with an irregular geometry. Here a method for conformal deposition of luminescent nanocrystals onto surfaces of varying geometries and materials is investigated. In a single reactor, silicon nanocrystals were synthesized in a nonthermal plasma and deposited directly onto substrates held in the plasma by a stand. The confirmation of conformal coatings onto the substrates was verified through the use of scanning electron microscopy. Preliminary results indicate conformal coatings and suggest that insulating surfaces exhibit greater nanocrystal agglomeration than conductive surfaces whose distribution shows greater uniformity. For the nanocrystals to exhibit the desired optical and electrical properties they must be crystalline: control of the crystallinity is accomplished by adjusting gas flow rates and the power to the plasma. Part of our current work is synthesizing and verifying that the coatings consist of crystalline nanocrystals and measuring the thickness of the deposited coatings. Ongoing work also includes studying the effects of thermal and electrical properties, and surface complexity on the degree of conformality.

 

 

 

Poster Number: ME-12

Authors: Alborz Izadi, Mayank Sinha, Sara Roccabianca, Rebecca Anthony

Title:  Silicon Nanocrystal Mechanical Property Investigations

 

Abstract: Flexible electronics have attracted a lot of interest in recent decades. To our knowledge there are few to no basic studies based on the mechanical properties of nanomaterials on flexible substrates, and the resulting opto-electric properties. In this study we will focus on fabrication of nanocrystals and deformable substrates. Silicon nanocrystals (SiNCs) will be produced and deposited onto flexible substrates, opening a new level of understanding of instabilities formed by nanomaterials. This work will help us to revolutionize next generation of photovoltaics, LEDs and other optoelectronic devices. We use a low -pressure plasma reactor excited using radiofrequency (RF) power to deposit SiNCs on polydimethylsiloxane (PDMS) as an elastomer substrate. The substrate is going to be pre-stretched underneath the orifice where the SiNCs accelerate and form a film on top of the PDMS. In order to focus on mechanical properties of SiNCs we apply stress on one direction and raster the substrate beneath the orifice in the same direction to provide uniform deposition of luminescent SiNCs on PDMS. We then relax the PDMS and preliminary results show that the NC films exhibit wrinkling patterns in a manifestation of surface instabilities. Since PDMS and films of SiNCs both have highly non-linear behavior, we will apply uniaxial tensile tests and nanoindenation to investigate the material properties of the bilayer depending on the geometrical characteristics of the NC films and PDMS substrates.

 

This work was supported in part by NSF under CBET Grant 1561964

 

 


 

Poster Number: ME-13

Authors: Hussam Hikmat Jabbar, Ahmed Naguib

Title:  Computational Study of a Vortex Ring Interacting with a Constant Temperature Heated Wall

 

Abstract: In this research, a computer simulation is conducted using ANSYS-Fluent to investigate the unsteady heat transfer resulting from the interaction of an axisymmetric vortex ring with a heated flat wall. The overarching goal of the research is to develop and experimentally characterize active flow control methodology to enhance the heat transfer rates in impinging jets. The present work isolates a fundamental feature of these flows; that involving the interaction of the jet vortices with the wall. This simplification facilitates understanding of the fundamental connection(s) between the flow features and thermal transport at the surface through simultaneous examination of the vorticity and the temperature fields, the hydrodynamic and the thermal boundary layers, and the Nusselt number. Ultimately, this understanding will be used to devise open-loop and adaptive flow control strategies to enhance the overall heat transfer rates from/to the wall.

 

 

 

Poster Number: ME-14

Authors: Sina Jahangiri Mamouri, Andre Benard

Title:  Modeling Oil-water Separation Using Membranes

 

Abstract: Oil-water separation is a critical aspect of operating an oil well and also constitutes a unit process critical for the success of oil spill cleanup. In the US, an average of 7 to 8 barrels of contaminated water are produced for one barrel of oil [1]. This so called produced water has oil concentrations of typically 100 to 5,000 mg/L [2]. These waters cannot be directly discharged into the environment if the oil concentration is less than the allowable concentration [3-6].

Deoiling of produced or impaired water represents a significant challenge for companies, communities, state and federal agencies. Centrifugation, air flotation, and hydrocyclone separation are the current methods of oil removal from produced water, however the efficiency of these methods decreases dramatically for droplets smaller than approximately 20 µm. More effective separation of oil-water mixtures into water and oil phases is a key technology that has potential to both decrease the environmental footprint of the oil and gas industry and improve human well-being in regions such as the Gulf of Mexico.

New technologies, enabled by recent breakthroughs in membrane separation processes and design of systems with advanced flow management offer tremendous potential for improving oil-water separation efficacy. In this project, the behavior of oil droplets and their interaction with membrane surfaces is studied using computer simulations; experiments are already available to validate the results. The behavior of a single and multiple droplets interacting with pores on the surface, with each other, and with the flowing stream is modeled (impingement, coalescence, pore entry, and removal). The information gathered from such models is used to develop population balance models for droplets on surfaces so as to improve the design and effectiveness of separation devices.

 

This work was supported in part by Fellowship from James Dyson Foundation; MSU Sustainability office fellowship; NSF partnership for international research and education (PIRE)

 

 

 

Poster Number: ME-15

Authors: Xue(Zoe) Jiang, Peter B. Lillehoj

Title:  Pneumatic Microvalves Fabricated by Multi-material 3D Printing

 

Abstract: We report an innovative and simple approach for fabricating pneumatic microvalves via an assembly-free 3D printing technique. These valves are based on monolithic elastomeric valves fabricated by multilayer soft lithography but circumvents the need for specialized layering, alignment and bonding. 3D printed microfluidic devices containing flow channels and pneumatic valves were fabricated and tested for functionality. Using these devices, we successfully demonstrate valve actuation for precise liquid flow control and on/off operation. The speed and simplicity of this approach make it a promising technique for rapid prototyping and manufacturing of 3D printed microfluidic devices with fully integrated components.

 

This work was supported in part by Bill and Melinda Gates Foundation

 


 

Poster Number: ME-16

Authors: Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil

Title:  Swing-up of Inertia Wheel Pendulum using Impulsive Control

 

Abstract: Inertia Wheel Pendulum (IWP) is an underactuated system. It consists of a planar pendulum with a rotating disc at the end attached to a motor. The torque applied by the motor causes a reaction torque on the pendulum link which is unactuated. We look at the problem of swing-up control of the inertia wheel pendulum from vertically downward equilibrium configuration to the upright equilibrium configuration using impulsive control and then switching the swing-up controller to a local stabilizing controller. As compared to previous studies of swing-up control of IWP that uses a continuous controller based on energy methods, the swing up time using our controller is much less. It has also been reported that global stabilizing controller that do not rely on switching tend to aggressively stabilize the equilibrium and require extremely high torque input to accomplish. Based on the dynamics of the system, we also present the reason for such behavior which was previously not known. Impulsive control is implemented using high gain feedback and a generalized approach is presented for reduction of peak impulses with respect to increase in the number of impulsive torques.

 

This work was supported in part by National Science Foundation

 

 

 

Poster Number: ME-17

Authors: Ali Kharazmi, Harold Schock

Title:  Three Dimensional Analysis of the Gas Flow in Piston Ring Pack

 

Abstract: A 3D model of the piston assembly is introduced to analyze the flow between the cylinder liner and the piston. A new program is developed to link between the conventional 1D models and Commercial CFD solvers. The effect of ring twist on mass flow rate and pressure across the piston is calculated using the introduced model.

 

 

 

Poster Number: ME-18

Authors: Ehsan Kharazmi, Mohsen Zayernouri

Title:  Operator-based Uncertainty Quantification (UQ) in Science and Engineering

 

Abstract: Mathematical models of physical phenomena contain design parameters, which are obtained from observable data. Stochastic fractional differential equations generalize the standard PDE models to those of fractional orders, and they offer attractive possibilities for robust modeling of complex multi-scale physical problems. In such models, the fractional orders are obtained from experimental sets of data. However, due to the inherent incompleteness of the data, uncertainty quantification is required to assess the uncertainties, associated with the randomness in the parameters. Moreover, the behavior of fractional models is sensitive to the fractional orders, which motivates the sensitivity analysis in order to develop numerical solvers to obtain the parameters in an iterative fashion. In this work, we consider a fractional differential equation (FDE) and a fractional partial differential equation (FPDE). We use Monte Carlo method and probabilistic collocation method to obtain the standard deviation of the solution and quantify the uncertainties of parameters. Moreover, we derive the sensitivity equations, corresponding to the order of fractional derivatives and develop an iterative algorithm, which employ the sensitivity equations along with the original FDE/FPDE to iteratively obtain the fractional derivative orders.

 

This work was supported in part by AFOSR Young Investigator Program (YIP) award on: "Data-Infused Fractional PDE Modelling and Simulation of Anomalous Transport" (FA9550-17-1-0150)

 

 

 

Poster Number: ME-19

Authors: Ruixue Christine Li, Guoming George Zhu, Kevin David Moran, Ruitao Song

Title:  In-cylinder Ionization Sensing with Ignition Coil Inductance Shorting

 

Abstract: An MSU patented technique to improve the frequency response of an in-cylinder ionization sensing circuit when used with a high energy (impedance) ignition coil on an internal combustion spark ignition engine. To be more specific, it is used to reduce the filtering effects of the ignition coil inductance by shorting the primary winding following the spark event and continuing through combustion process. The experimental results with improvement on engine knock detection will be presented.

 

Poster Number: ME-20

Authors: Tung-Yi Lin, Sina Parsnejad, Linlin Tu, Trey T. Pfeiffer, Andrew J. Mason, Guoliang Xing, Peter Lillehoj

Title:  Finger-powered Microfluidic Electrochemical Assay for Point-of-care Testing

 

Abstract: Many point-of-care tests utilize microfluidics for liquid transport. However, two key challenges for microfluidic systems are systems integration and fluidic handling, which typically involves external components and/or power sources. Here, we demonstrate a finger-powered microfluidic electrochemical assay for rapid measurements of protein biomarkers. This device employs a valveless, piston-based pumping mechanism which utilizes a human finger for the actuation force. Liquids are driven inside microchannels by pressing on the pistons which generates a pressure-driven flow. Reagents are preloaded in microwells allowing for the entire testing procedure to be completed on chip. For proof-of-concept, this device was used to detect Plasmodium falciparum histidine-rich protein-2 (PfHRP2) in human plasma samples using a mobile phone detection platform. This device can measure PfHRP2 from 0.1 to 20 µg/mL with high specificity. Furthermore, each measurement can be completed in <= 6 min. Based on its simplicity, portability and excellent analytical performance, this device is a promising platform for point-of-care testing, particularly in remote and resource-limited regions.

 

This work was supported in part by National Institutes of Health (R01AI113257)

 

 

 

Poster Number: ME-21

Authors: Suihan Liu, Rigoberto Burgueño

Title:  Controlled Elastic Postbuckling of Bilaterally Constrained Non-prismatic Columns: Application to Enhanced Quasi-static Energy Harvesters

 

Abstract: Axially compressed bilaterally constrained columns, which can attain multiple snap-through buckling events in their elastic postbuckling response, can be used as energy concentrators and mechanical triggers to transform external quasi-static displacement input to local high-rate motions and excite vibration-based piezoelectric transducers for energy harvesting devices. However, the buckling location with highest kinetic energy release along the element, and where piezoelectric oscillators should be optimally placed, cannot be controlled or isolated due to the changing buckling configurations. This work proposes the concept of stiffness variations along the column to gain control of the buckling location for optimal placement of piezoelectric transducers. Prototyped non-prismatic columns with piece-wise varying thickness were fabricated through 3D printing for experimental characterization and numerical simulations were conducted using the finite element method. A simple theoretical model was also developed based on the stationary potential energy principle for predicting the critical line contact segment that triggers snap-through events and the buckling morphologies as compression proceeds. Results confirm that non-prismatic column designs allow control of the buckling location in the elastic postbuckling regime. Compared to prismatic columns, non-prismatic designs can attain a concentrated kinetic energy release spot and a higher number of snap-buckling mode transitions under the same global strain. The direct relation between the column’s dynamic response and the output voltage from piezoelectric oscillator transducers allows the tailorable postbuckling response of non-prismatic columns to be used as multi-stable energy concentrators with enhanced performance in micro-energy harvesters.

 

This work was supported in part by U.S. National Science Foundation under grant number ECCS-1408506

 

 

 

Poster Number: ME-22

Authors: Xiyuan Liu, Peter B. Lillehoj

Title:  Embroidered Biosensors on Gauze for Rapid Electrochemical Measurements

 

Abstract: We report a unique process for fabricating robust, flexible electrodes onto medical gauze and wound dressing via embroidery. Embroidered electrodes were utilized as electrochemical biosensors for measurements of wound-related biomarkers. Proof-of-concept was carried out by performing quantitative measurements of uric acid, a biomarker for wound healing, in simulated wound fluid. This gauze-based sensor exhibits high specificity and linearity from 0 &#956;M to 800 &#956;M. Additionally, this biosensor exhibits excellent resilience against mechanical deformation, making it a promising platform for noninvasive wound monitoring.

 

This work was supported in part by National Science Foundation CAREER award (ECCS-135056)

 

 

 

 

Poster Number: ME-23

Authors: Rakshith Lokesh, Rajiv Ranganathan

 

Title:  How do Humans Exploit Mechanical Redundancy when Faced with Increasing Task Difficulty?

 

Abstract: Humans can successfully perform goal-directed movements, even in the presence of redundancy at multiple levels. How the nervous system uses this redundancy when learning remains an open question. The uncontrolled manifold hypothesis (UCM) postulates that the nervous system exploits redundancy by allowing variability in the “null space” of the task while controlling the variability in the task space. The aim of our study was to test this hypothesis by examining how participants exploit variability in the null space, when faced with tasks of different difficulty. Participants performed a bimanual tracing task of a complex trajectory made up of several sinusoidal segments, and we varied task difficulty by adjusting the width of the “track” they were permitted to stay within. The mechanical redundancy in this task arose from the fact that the cursor used for the tracing was defined as the average position of the two hands. Two groups of 8 subjects each were tested on two different track widths and each subject performed 124 trials each day on a two-day schedule. We measured how redundancy is exploited by measuring the variability in the null space of the task. Our preliminary results show that null space variance reduces with learning, and had no correlation to changing trajectory widths. These results provide better understanding of how our nervous system resolves interlimb redundancy when learning and promotes development of novel methods in upper limb neurorehabilitation.

 

 

 

Poster Number: ME-24

Authors: Yifan Men, Guoming Zhu

Title:  Model-based Calibration of the Reaction-based Diesel Combustion Dynamics

 

Abstract: A control-oriented reaction-based combustion model is implemented and used to simulate the combustion process in a diesel engine. The model integrates a homogeneous thermodynamic system with a two-step chemical reaction mechanism that consists of six species. The accuracy of the model is evaluated by comparing with experimental data from a GM 6.6 L, 8 cylinder Duramax engine. The model is calibrated for different key points over the entire engine map as well as various injection timings and exhaust gas recirculation (EGR) ratio using an automated calibration algorithm. The reaction based model is shown to provide accurate predictions of in-cylinder pressure, temperature, mass-fraction-burned and heat release rate. As an alternative to Wiebe-based method, this approach could lead to a better model with less calibration effort. The improvement is due to the fact that the burn rate is online calculated based upon the dominated fuel chemical components and combustion chamber properties, such as temperature, oxygen and burned gas concentration, etc.

 

This work was supported in part by General Motors Company

 

 

 

Poster Number: ME-25

Authors: Yen Nguyen, Thomas Pence, Indrek Wichman

Title:  Crack Formation and Propagation in an Elastic Medium Undergoing Thermal Pyrolysis

 

Abstract: A theoretical and numerical model for the degradation of solid materials in combustion is developed. As solid materials are heated by the flame, they undergo an internal thermo- chemical breakdown process known as pyrolysis. As the pyrolysis front propagates into the sample, a charring layer is left behind which contains voids, fractures and defects. Cracks propagate to release tensile stresses accumulated when the sample is losing its mass. The crack front may precede the pyrolysis front into the sample. Crack patterns and fracture behaviors may vary depending on material properties and heating condition. Cracks

cause loss of material integrity, forming isolated loops or fragments. They also concentrate the stresses and reduce the ability to withstand external loads. Cracks expose uncharred materials to flame, accelerating combustion. The process is highly nonlinear: crack patterns display fractal behavior. Two heating conditions along with various values of material strength are examined: each combination yields different crack patterns for which its morphological statistics

are calculated using image analysis (computational diagnostics). Fundamental theoretical principles are uncovered.

 

 

 

 

 

Poster Number: ME-26

Authors: Kyle O'Shea, Rebecca Anthony

Title:  Surface Treatment of Silicon Nanocrystals at Atmospheric Pressure

 

Abstract: Silicon Nanocrystals (SiNCs) show great potential in applications as LEDs and other optoelectronic devices; properties such as photoluminescence (PL) and reflectivity indicate how effectively a SiNC sample behaves as an LED. Here, we synthesize SiNCs using a non-thermal plasma reactor consisting of Argon (Ar), Silane (SiH4), and Hydrogen (H2) gases. In particular, this study investigates the use of a dielectric barrier discharge (DBD) radio frequency (RF) reactor to generate a non-thermal argon plasma at atmospheric pressure which is used for additional treatment of SiNC samples deposited on a copper substrate. Rather than utilizing one positive and one negative electrode around the perimeter of a glass tube to generate a plasma, a DBD reactor uses a coiled electrode around the outside of the glass and a grounded electrode that runs down the center of the tube. The current study seeks to discover how additional surface treatment of SiNCs with a DBD reactor impacts their optoelectronic properties.

 

 

 

Poster Number: ME-27

Authors: Raul Quispe-Abad, Norbert H. Mueller

Title:  Exergy Approach to Evaluate the Performance of Unsteady Expansion Process in Rotors with Curved Channels

 

Abstract: The Wave Disc Engine (WDE) is a novel idea among the wave rotor technology. This new engine concept is a radial rotor in which the typical processes of an Internal Combustion Engine (Compression, Combustion, and Expansion) are realized. For the torque production, the unsteady expansion process of outflowing combusted gases is used. The evaluation of the performance of torque generation for conventional turbines typically considers only steady effects and the efficiency method is based on the energy approach. For the unsteady expansion process, an unsteady component is added to this conventional analysis and because of that a different method to evaluate the efficiency is required. This research is focused on the evaluation of the performance of the unsteady expansion process by using the criterion of the Second Law of Thermodynamic efficiency. The combination of Computational Fluid Dynamic analysis and the Exergy approach, the efficiency is evaluated. Two findings will be pointed out: The percentages of the efficiency based on this new approach and the potential option that is brought out to improve the torque extracted. The outcome of this research contributes to maximizing the work extraction of Wave Disc Engine (WDE) technology. This will be a step forward to a near future of the fabrication of the WDE for portable and residential scale power generation.

 

 

 

Poster Number: ME-28

Authors: Matt Ryerkerk, Ron Averill, Kalyanmoy Deb, Erik Goodman

Title:  Length Niching Selection Operator for Metameric Genetic Algorithms

 

Abstract: In many optimization problems one of the goals is to determine the optimal number of analogous components to include in the system. Examples include the number of sensors in a coverage problem, the number of turbines in a wind farm problem, and the number of plies in a laminate stacking problem. We classify these under the proposed term of metameric problems. Such problems can be solved by assuming a fixed number of components, however this may lead to sub-optimal solutions. A better method is to allow the number of components to vary among solutions, however the changing dimensionality of the search space makes the application of gradient-based methods difficult. Genetic Algorithms using a segmented variable-length genome are a suitable alternative, but modifications are required to the traditional genetic operators. In literature these modifications are frequently limited to the recombination and mutation operators, however in some cases the selection operator must also be modified to reach optimal solutions. We demonstrate the effectiveness of a proposed length-niching selection operator and compare it to standard selection operators as well as a traditional fixed-length genetic algorithm.

 

This work was supported in part by BEACON (An NSF Center for the Study of Evolution in Action)

 

 

 

 

 

 

 

 

Poster Number: ME-29

Authors: Alireza Safaripour, Anton Ryabtsev, Shahram Pouya, Marcos Dantus, Manoochehr Koochesfahani

Title:  A Novel Vorticity Measurement Technique Using Laguerre-Gaussian Laser Beams with Orbital Angular Momentum

 

Abstract: Vorticity is one of the most important dynamic flow variables and is fundamental to the basic flow physics of many areas of fluid dynamics, including aerodynamics, turbulent flows and chaotic motion. Vorticity characterizes twice the local rotation rate of a fluid particle and is mathematically defined as the curl of the flow velocity vector. The most common vorticity measurement techniques rely on determining the velocity gradients from a measured velocity field to estimate the spatially averaged vorticity over a small region. This work presents a novel technique to measure the vorticity of a fluid flow in a direct and non-intrusive fashion. This technique utilizes a superposition of Laguerre-Gaussian (LG) laser beams focused inside the flow as an optical probe and takes advantage of the Rotational Doppler Effect (RDE) from seed micron-sized particles going through the beam focal volume. Sample experiments are performed to measure the vorticity in a fluid flow with a well-characterized vorticity field and the results are in excellent agreement with the expected values. This method allows for localized real-time determination of vorticity in a fluid flow with three-dimensional resolution.

 

This work was supported in part by Air Force Office of Scientific Research (AFOSR) FA9550-14-1-0312

 

 

 

Poster Number: ME-30

Authors: Mehdi Samiee, Mohsen Zayernouri

Title:  A Fractional PDE Approach to Turbulent Mixing

 

Abstract: It has been experimentally and theoretically shown that even in the most ideal cases of homogeneous and isotropic turbulence, the statistical distributions are asymmetric and heavy-tailed. Similar observations, in addition to high peaks, have been made in grid turbulence and atmospheric boundary layer. In the aforementioned problems, the skewness, as a measure of asymmetry, is non-zero and negative, also the flatness (kurtosis), as a notion of the tail heaviness in the distribution, significantly exceeds the Gaussian value 3, reflecting a strong non-Gaussianity. In this talk, we demonstrate that the existence of such anomalous characteristics e.g., heavy tails, asymmetric distributions, and high peaks can naturally put the phenomenology of Taylor, Richardson, and Kolmogorov in broader framework, where the generalizing fractional Brownian motions and stochastic Lévy jump processes (or Lévy flights), investigated in the context of fractional PDEs in the fluid limit, can physically and mathematically explain, hence, predict the notion of anomalously enhanced (sub-to-super) diffusion and self-similar features in passive scalar turbulence.

We propose a generalizing fractional order transport model of advection-diffusion kind with fractional time- and space-derivatives, governing the evolution of passive scalar turbulence. This approach allows one to incorporate the nonlocal and memory effects in the underlying anomalous diffusion i.e., sub-to-standard diffusion to model the trapping of particles inside the eddied, and super-diffusion associated with the sudden jumps of particles from one coherent region to another. For this nonlocal model, we develop a high order numerical (spectral) method in addition to a fast solver, examined in the context of some canonical problems.

 

 

 

Poster Number: ME-31

Authors: Ayse Sapmaz, Brian F. Feeny

Title:  In-plane Blade-hub Dynamics of Horizontal-axis Wind Turbine with Mistuned Blades

 

Abstract: Understanding vibration of the wind turbine blades is of fundamental importance. This poster regards the effect of blade mistuning on the coupled blade-hub dynamics. Unavoidably, at any stage of the wind turbine, the set of blades will not be precisely identical due to the in-homogeneous material, manufacturer tolerances etc. This poster is based on blade-hub dynamics of a horizontal axis wind turbine with mistuned blade. The equations of motion are derived for the wind turbine blades and hub exposed to centrifugal effects, gravitational and cyclic aerodynamic forces. The equations are coupled. To decoupled them, the independent variable is changed from time to rotor angle. The blade equations include parametric and direct excitation terms. The method of multiple scales is applied to examine response of the system. This analysis shows that superharmonic and primary resonances exist. Resonance cases and the relations between response amplitude and frequency are studied.

 

This work was supported in part by National Science Foundation under grant CMMI-1335177; Republic of Turkey / Ministry of National Education

 

 

Poster Number: ME-32

Authors: Justin Scott, Tamara R. Bush

Title:  Pressure Ulcer Prevention in High Risk Individuals

 

Abstract: Many people sit in a chair for part of their day, getting up and adjusting themselves without a thought. But there are those who experience the complications associated with sitting in a chair all day on a regular basis. Pressure ulcers (PU) are wounds that can penetrate to the bone and are caused by a lack of nutrients to tissue. Their long healing time means the average cost of a hospital visit to treat a PU is $48,000 [1]. This does not consider lost work or deterioration of quality of life. The constant load on the buttocks and backs of wheelchair bound individuals put them at a high risk for developing PUs. External pressure diminishes blood flow to loaded areas, resulting in malnourished tissue and eventually tissue death. The 282,000 people [2] with spinal cord injuries (SCI) in the United States are prone to PUs. Another factor with SCI patients is that they cannot feel pressure points. They cannot feel discomfort after long periods of loading, nor can they adjust without thinking, making the formation of an ulcer more likely. The work aims to shift loading from the ischial tuberosities, a PU prone region, using an articulating chair to move the body. Cyclically loading and unloading tissues should reduce the chance of a PU in a specific region, such as the ischial tuberosities. [1] National Spinal Cord Injury Statistical Center, 2016. [2] Brem, H., et al. American Journal of Surgery, 200(4): 473-477, 2010.

 

This work was supported in part by NSF CBET, grant number 1603646

 

 

 

Poster Number: ME-33

Authors: Sheikh Mohammad Shavik, Lik Chuan Lee

Title:  Assessment of Organ-scale Left Ventricular Mechanics and Physiology using a Cellular-based Active Contraction Model

 

Abstract: Left ventricular (LV) finite element (FE) models based on cellular descriptions of active contraction are used increasingly to model ventricular mechanics associated with normal and abnormal heart functions. As the active contraction models were developed using data from single cell experiments, it is unknown if they are able to reproduce physiological behavior observed at the organ level. The goal of this work is to assess organ-scale physiological behaviors that are derived from a cellular-based LV FE model. The electro-mechanical model of LV was developed by coupling the cellular electrophysiology model of Winslow et al. (1999) with the active tension development model of Rice et al. (2008). This model was coupled to a lumped parameter closed-loop circulatory model that takes into account atrial contraction. Different loading conditions were simulated and the model predictions of (1) pressure-volume (PV) loops, (2) myocardial oxygen consumption (mVO2) and mechanical work relationship, and (3) three-dimensional strain were analyzed. The results show that the model is able to reproduce a linear end-systolic pressure-volume relationship (ESPVR) and a curvilinear end-diastolic pressure-volume relationship (EDPVR) using the PV loops generated under different loading conditions. The model prediction agrees with the linear relationship between mVO2 and PVA as observed experimentally. Finally, our model predicts that changes in the loading conditions affect the longitudinal, circumferential and radial strain behavior over the cardiac cycle. However, interestingly, the peak longitudinal and circumferential strain are less sensitive to the loading conditions than the radial strain.

 

 

Poster Number: ME-34

Authors: Mayank Sinha, Alborz Izadi, Shwan Al-Howrami, Rebecca Anthony, Sara Roccabianca

Title:  Mechanical Characterization and Modeling of the Behavior of Nanocrystals-PDMS Bilayers

 

Abstract: A new approach to engineer the microstructure of functional materials is to use the formation of mechanical instabilities to initiate or moderate the microscale ordering of materials. While semiconductor nanocrystals (NC) are beginning to be used in stretchable devices, to date there are few studies on the mechanical behavior of NC on stretchable surfaces. We want to characterize the mechanical behavior of a bilayer of PDMS and NCs by experimentally observing the stress-strain behavior of both the components. Two types of experiments are to be performed, a uniaxial tensile test and a nanoindentation test, to calculate the material properties of the bilayer depending on the geometrical characteristics of the NC film. PDMS and NCs both have highly non-linear behavior, with the former being extensively studied over the past 50 years. PDMS is generally defined as an isotropic, homogeneous, hyperelastic and incompressible material, and is characterized by strain energy functions defined for rubber-like materials. For silicon NCs, we propose to adopt different strain energy functions which have proven to be descriptive of elasto-plastic materials to fit the results obtained from the nanoindentation and uniaxial tensile tests.

 

This work was supported in part by NSF Award 1561964

Poster Number: ME-35

Authors: Ruitao Song, Guoming Zhu

Title:  Control-oriented Model for a Gasoline Turbulent Jet Ignition Engine

 

Abstract: A control-oriented engine model is necessary for developing and validating the associated engine control strategies. For engines equipped with the turbulent jet ignition (TJI) system, the interaction between the pre- and main-combustion chambers should be considered in the control-oriented model for developing control strategies that optimize the overall thermal efficiency in real-time. Therefore, a two-zone combustion model based on the newly proposed parameter-varying Wiebe function is proposed. Since the engine uses the liquid fuel, a pre-chamber air-fuel mixing and vaporization model is also developed. The model was validated using the experimental data from a single cylinder TJI engine under different operational conditions, and the simulation results show a good agreement with the experimental data.

 

This work was supported in part by US National Science Foundation and Department of Energy under contract number CBET-1258581

 

 

 

Poster Number: ME-36

Authors: Yifeng Tian, Farhad Jaberi, Daniel Livescu, Zhaorui Li

Title:  Shock-capturing Simulations of Variable Density Shock-turbulence Interactions

 

Abstract: The interaction between an isotropic multi-fluid turbulence with a planar shock wave is studied using turbulence resolved shock-capturing simulations. This problem is an extension of the canonical Shock-Turbulence Interaction (STI), with the effects of strong density variations (from compositional changes) taken into consideration. To establish shock-capturing simulation as a reliable method for studying STI, LIA convergence tests are conducted to show that LIA limits can be approximated at relatively high Reynolds number and low turbulent Mach number, when the separation between numerical shock thickness and turbulent length scales is adequate. This agrees well with previous DNS study. When variable density effects are introduced, turbulence structure is modified more by the normal shock, with a differential distribution of turbulent statistics in regions with different densities, resulting in a strong mixing asymmetry in the post-shock region. Turbulence achieves similar axisymmetric two-dimensional local state right after the shock wave in the multi-fluid case, but has a faster return to three-dimensional isotropic structure when compared to the single-fluid case. The characteristics of post-shock thermodynamic fluctuations are also affected and are dominated by shock strength fluctuations that result from the compositional changes.

 

This work was supported in part by Los Alamos National Laboratory

 

 

 

Poster Number: ME-37

Authors: Tyler Tuttle, Alex Tyckoski, Anthony Tomaski, Sara Roccabianca

Title:  Comparison of Mechanical Properties of the Urinary Bladder Wall in Apex-to-base and Circumferential Directions

 

Abstract: The urinary bladder (UB) is a musculomembranous hollow organ whose main function is to store and void urine in a controlled manner. As urine is collected in the bladder, the bladder enlarges so that the internal pressure remains relatively constant. Alterations to this cycle, or obstruction of the urethral outlet, can cause a number of storage or voiding disorders. The parameter that urologists use to diagnose loss of functionality in the bladder is compliance (change in volume over change in pressure during filling). Compliance values have a wide range of “normality” reported in the literature. We submit that measurement of stress in the UB wall could be a better predictor of normal functionality of the bladder. For this reason, the focus of this study is to experimentally measure the mechanical properties of the UB wall. Specifically, four intact pig UB were collected from the MSU Meat Laboratory, then cleaned of contents and adjacent tissues. Four samples from each UB were harvested along the apex-to-base axis from four anatomical regions (dorsal, ventral, trigon, and lower body). Specimens were either tested fresh, or stored following three different storage protocols before testing. Samples were subjected to a uniaxial tensile test. The collected data was modeled using the constrained mixture theory. The data indicated that the storage protocols yield results that are not significantly different, mechanical responses are reproducible across pigs, and differences exist between anatomical locations in pig bladders. The model showed good predictive capabilities in pig UB.

 

 

 

 

Poster Number: ME-38

Authors: Miao Wang, Xinran Xiao

Title:  A Multiphysics Microstructure-resolved Model for Silicon Anode Lithium-ion Batteries

 

Abstract: Silicon (Si) is one of the most promising next generation anode materials for lithium-ion batteries (LIB), but the use of Si in LIBs has been rather limited. The main challenge is its large volume change (up to 300%) during battery cycling. This can lead to the fracture of Si, failure at the interfaces between electrode components, and large dimensional change on the cell level. To optimize the Si electrode/battery design, a model that considers the interactions of different cell components is needed. This paper presents the development of a multiphysics microstructure-resolved model (MRM) for LIB cells with a-Si anode. The model considered the electrochemical reactions, Li transports in electrolyte and electrodes, dimensional changes and stresses, property evolution with the structure, and the coupling relationships. Important model parameters, such as the diffusivity, reaction rate constant and apparent transfer coefficient, were determined by correlating the simulation results to experiments. The model was validated with experimental results in the literature. The use of this model was demonstrated in a parameter study of Si nanowall|Li cells. The specific and volumetric capacities of the cell as a function of size, length/size ratio, spacing of the nanostructure, and the Li+ concentration in electrolyte were investigated.

 

This work was supported in part by NSF CMMI 1030821

 

 

 

Poster Number: ME-39

Authors: Yingxu Wang, George Zhu

Title:  Control on Apple Tree Watering System

 

Abstract: A new method of planting apple trees is deployed at the Michigan State University Clarksville Facility, where the apple trees are planned with very high density in a way similar to grape vineyard on the farm. A watering and pesticide spray system is developed along the tree columns with hundreds sprayers. For the purpose of monitoring spray results and automatic control the spray process, a drone is modified to be equipped with both conventional HD and IR cameras and used to monitor the spray results based on the images from both HD and IR cameras; and wireless flow sensing system are under development  and it will be used to make the spray process automated.

 

This work was supported in part by United States Department of Agriculture

 

 

 

Poster Number: ME-40

Authors: Wei Li, David Torres, Tongyu Wang, Chuan Wang, Nelson Sepulveda

Title:  Flexible and Biocompatible Polypropylene Ferroelectret Nanogenerator (FENG): On the Path Toward Wearable Devices Powered by Human Motion

 

Abstract: Recently, there has been tremendous research efforts on the development of energy harvesters that can scavenge energy from ubiquitous forms of mechanical energy. The most studied mechanisms are based on the use of piezoelectric and triboelectric effects. Polypropylene ferroelectret (PPFE) is introduced here as the active material in an efficient, flexible, and biocompatible ferroelectret nanogenerator (FENG) device. PPFE is charged polymers with empty voids and inorganic particles that create giant dipoles across the material's thickness. Upon applied pressure, the change in the dipole moments generate a change of the accumulated electric charge on each surface of the PPFE film, resulting in a potential difference between the two electrodes of the FENG. The mechanical-electrical energy conversion mechanism in PPFE films is described by finite element method (FEM). Further investigation of the developed device shows that the magnitudes of the generated voltage and current signals are doubled each time the device is folded, and an increase with magnitude or frequency of the mechanical input is observed. The developed FENGs is sufficient to light 20 commercial green and blue light-emitting diodes (LEDs), and realize a self-powered liquid-crystal display (LCD) that harvests energy from user's touch. A self-powered flexible/foldable keyboard is also demonstrated.

 

This work was supported in part by National Science Foundation (NSF ECCS Award \#1139773 (NSF CAREER Award) and \#ECCS-1306311)

 

 

 

 

Poster Number: ME-41

Authors: Ce Xi, Lee Lik Chuan

Title:  Finite Element Implementation and Analysis of a Structural Three-dimensional Constitutive Law for the Passive Myocardium

 

Abstract: A three-dimensional constitutive law is implemented in the left ventricle FE geometry. Its formulation is based on a structural approach in which the total strain energy of the tissue is the sum of the strain energies of its constituents: the muscle fibers, the collagen fibers and the fluid matrix which embeds them. The material law accounts for the specific structural and mechanical properties of the tissue, namely, the spatial orientation of the comprising fibers, their waviness in the unstressed state and their stress-strain relationship when stretched. Material parameters are adjusted and varied to analyze their influence on stress distribution and myocardium tissue properties.

 

 

 

Poster Number: ME-42

Authors: Peng Xu, Thomas Bieler, Neil Wright

Title:  Monte Carlo Simulation of the Lattice Thermal Conductivity of Superconducting Niobium Thin Films

 

Abstract: Understanding the scattering mechanisms is essential for modeling the thermal conductivity of Nb in bulk or in thin films. Such models improve the design process for developing the next generation of Superconducting Radio Frequency (SRF) particle accelerators. Thermal conductivity is composed of electron and lattice components. In superconductors, these components are of the same order of magnitude. The conventional model of thermal conductivity in superconductors requires estimating several parameters from experimental results. Here, an energy-based variance reduced Monte Carlo simulation is used to predict the lattice thermal conductivity of bulk superconducting Nb as well as Nb thin film by considering phonon-electron scattering and boundary scattering. The model was first verified by comparing the predicted thermal conductivity in bulk Si and Si nanowires with experimental data. When applied to Nb, predictions of the temperature dependent thermal conductivity due to boundary scattering agree well with a kinetic theory model and with the experimental data. Results also show that boundary scattering dominates for T smaller than 2K where the phonon mean free path is comparable to the size of the sample, and that phonon-electron scattering is important when T is greater than 2K. A local maximum in thermal conductivity (i.e., the phonon peak) appears at temperatures of approximately 2 K in appropriately heat-treated material.

 

 

 

Poster Number: ME-43

Authors: Shutian Yan, Xinran Xiao

Title:  Characterization of the Through Thickness Mechanical Property of Thin Polymer Films

 

Abstract: Thin polymer films have a wide range of applications. The mechanical properties of the films play an important role to their performances and functions. For example, porous thin polymer films are often the choice of materials for separators in Li-ion batteries. The mechanical integrity of the separator is critical to the durability and the safety of the batteries. To improve the separator design, it is desired to know the stresses experienced by a separator in a battery under different charging-discharging cycles and in the events of impact. Such information can be estimated through numerical simulations using multiphysics models. The stress-strain response of the separator is a required input. The in-plane stress-strain behavior of a thin polymer film may be measured using common lab equipment. The characterization of the through thickness mechanical properties is far more challenging. The battery separator is usually 20~30 micron in thickness. To obtain the stress-strain behavior, the displacement measurement must have a submicron resolution. In this work, we investigate a capacitance based displacement measurement method. Our preliminary study shows that this method can achieve a resolution of <0.5 micron. As shown in previous studies, both the in-plane and the through thickness mechanical properties are lower when tested in electrolyte solutions. Therefore, the mechanical properties measured in electrolyte solutions are used to represent the material behavior in the battery environment. In this work, a special testing fixture with capacitance based displacement measurement has been designed and used for through thickness behavior characterization in solutions.

 

This work was supported in part by National Science Foundation and General Motors

 


 

Poster Number: ME-44

Authors: Yaozhong Zhang, Junghoon Yeom

Title:  Development of Soft-based Micromotors for Water Decontamination

 

Abstract: The pollution crisis derived from scalable use of chemicals and biologicals has greatly affected humans’ health and global economy in past decades, whereas the conventional wastewater treatment plants have a hard time cleaning those emerged contaminants. In this circumstance photocatalytic degradation is developed as one promising approach to remove water contaminants caused by organic compounds. Although a large number of nanoparticle- or nanopowder-based photocatalysts have been fabricated, the challenges such as easy-agglomeration and poor recyclability impede their practical application. Recently, the immobilized photocatalytic system, especially the micromotor strategy attracts a considerable attention because the extendable configuration may address the abovementioned issues. For example the multifunctionality enables the micromotor freely swimming while decontaminating in water, where the self-propelled movement renders photocatalysts the continuous separation and achieves rapid pollutant degradation. Up to now with the assistance of template the micromotors are fabricated in reliableness and cost-effectiveness. However the limitations such as complicated instruments and poor geometry diversity still remain. Here we report a novel fabrication technique to create pollutant-degrading, self-propelled, micro soft-robots whose surface is decorated with the high surface-area, photocatalytic ZnO nanowire array. TiO2 and ZnO are the preferable photocatalysts due to their remarkable degradability and stability. The proposed micromotor is based on a sub-millimeter, hierarchical, self-folded polymeric structure integrated with functional inorganic nanomaterials that confer desired functionalities such as photodegradation and self-propulsion. To our knowledge, this type of micromotor platform has never been published, and we believe it would provide us with an opportunity to incorporate multiple functionalities.

 

 

 

Poster Number: ME-45

Authors: Wu Zhou, Dahsin Liu

Title:  Analyzing Dynamic Fracture Process in Fiber-reinforced Composite Materials with a Peridynamic Model

 

Abstract: A bond-based peridynamic model was developed to study in-plane dynamic fracture process in orthotropic composites. The peridynamic material constant was extended to a continuous micro-modulus Cθ for orthotropic materials. Cθ changes continuously from the fiber direction to the transverse direction with an effective orthotropy. Moreover, this model investigated the impact dynamic fracture process by inputting the in-situ crack velocity related dynamic toughness for the first time. Besides the final failure status, the fracture process and crack velocity can be predicted more accurately by using the in-situ dynamic fracture energy. The simulation was validated by comparison to the experimental results.

 

This work was supported in part by US Army Research Laboratory (ARL); Department of Mechanical Engineering, MSU

 

 

 

Poster Number: ME-46

Authors: Yifeng Tian, Farhad Jaberi, Daniel Livescu, Zhaorui Li

Title:  Shock-capturing Simulations of Variable Density Shock-turbulence Interactions

 

Abstract: The interaction between an isotropic multi-fluid turbulence with a planar shock wave is studied using turbulence resolved shock-capturing simulations. This problem is an extension of the canonical Shock-Turbulence Interaction (STI), with the effects of strong density variations (from compositional changes) taken into consideration. To establish shock-capturing simulation as a reliable method for studying STI, LIA convergence tests are conducted to show that LIA limits can be approximated at relatively high Reynolds number and low turbulent Mach number, when the separation between numerical shock thickness and turbulent length scales is adequate. This agrees well with previous DNS study. When variable density effects are introduced, turbulence structure is modified more by the normal shock, with a differential distribution of turbulent statistics in regions with different densities, resulting in a strong mixing asymmetry in the post-shock region. Turbulence achieves similar axisymmetric two-dimensional local state right after the shock wave in the multi-fluid case, but has a faster return to three-dimensional isotropic structure when compared to the single-fluid case. The characteristics of post-shock thermodynamic fluctuations are also affected and are dominated by shock strength fluctuations that result from the compositional changes.

 

This work was supported in part by Los Alamos National Laboratory