bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational Evaluation of a Novel Aerodynamic Road Vehicle Design and Drag Reduction Using Vortex Generators
Authors: Arora B. B. , Suri Ujjwal , Garg Utkarsh , Das Shraman , Kumar Sushrut 
Published: January 2020

Abstract
Vehicle aerodynamics is a prime domain of research and development. Multiple active and passive aerodynamic systems have been applied for its enhancement. The reduction of drag plays a pivotal role in the improvement of vehicle aerodynamic performance. The present paper studies the innovative design of a road vehicle for a fuel efficiency challenge, implemented for optimal drag reduction. Vortex generators are utilized as a passive aerodynamic feature for further minimization of the wake region size and reduction of pressure drag. High fidelity computational fluid dynamics simulations were applied for the evaluation of this design. Data was collated from simulations for both the cases, with and without the usage of vortex generators and compared objectively. The results of the study establish that the vehicle design has an exceptionally low drag coefficient. It also exhibits a strong reduction in drag when the vortex generators are fitted. These results reveal that the design can be deployed for production as a worthy competition vehicle.
Meshing Characteristics and Engagement of Anti-Backlash Single- and Double-Roller Enveloping Hourglass Worm Gear
Authors: Deng Xingqiao , Wang Jie , Wang Shike , Wang Shisong , Liu Yucheng , He Ge 
Published: January 2020

Abstract
Anti-backlash roller enveloping hourglass worm gears, as a new precision transmission system, has been extensively applied in robot joint design, packaging production line, and CNC (computer numerical control) machine tools. However, their corresponding transmission principles are seldom reported in the literature. Based on the theories of differential geometry and gear meshing, this paper carefully analyzes and compares meshing characteristics of anti-backlash single- and double-roller enveloping hourglass worm gears in terms of their transmission principle, engagement equation, induced normal curvature, lubrication angle, autorotation angle, entrainment velocity, helix angle, and distribution of contact curves. Major differences between these two roller enveloping hourglass worms are theoretically demonstrated through this study. Our results show that the anti-backlash single-roller enveloping hourglass worm (ASEHW) gears provide better performance with respect to gear meshing and transmission than the anti-backlash double-roller enveloping hour glass worm (ADEHW) gears. Also, compared with the ADEHW gears, the ASEHW gears are easier to fabricate, install, and calibrate. However, the ADEHW gears are more auto-adjustable in eliminating gear backlash. The outcomes of this study will form a theoretical background for futuristic design, application, and promotion of the anti-backlash roller enveloping hourglass worm gears.
Effect of Silicone Damping on Work Vibration in CNC Milling Process
Authors: Rahman AHM E. , Abu-Mahfouz Issam , Carbaugh Scott 
Published: January 2020

Abstract
Vibration dampening in machining processes is an important part of a machine being precise, low maintenance, and long lasting. Being able to utilize dampening materials in the design of machinery in existing structural tubing could allow designers to isolate vibration sources from critical components more effectively than with current methods. The purpose of this research was to show and analyze the effect of dampening materials undergoing specific machining vibration. An experiment was designed that used hollow columns both with and without dampening material and a CNC Mill to generate different types of vibration. These vibrations are detected using accelerometers at the top and bottom of the structure. By creating a variable matrix testing different viscosity dampening materials, different spindle speed, and different depth of cut, vibration with different frequency and amplitude was tested. By analyzing the characteristics of the vibration transmitted by the structure without a dampening material compared to that same vibration with a dampening material, a conclusion was made as to whether these materials dampen machining vibration.
Validation of an Atomistic Field Theory for Contact Electrification Using a MEMS Load Cell
Authors: Hieber Tyler J. , Cheikh Mohamad Ibrahim , Chen James M. , Leseman Zayd C. 
Published: January 2020

Abstract
This work depicts an experimental method for the validation of an Atomistic Field Theory (AFT) model for contact electrification of dielectrics. The AFT model is used to simulate the effects of Triboelectric Nanogenerators (TENGs) for energy harvesting. Recently, the AFT model has shown that contact electrification can be described by the induced surface dipoles when two dissimilar materials are brought into close contact assuming that the crystal lattices are free of defects, no residual strain in the materials is present and that the experiment is performed in vacuum. These simulations have been used to predict the induced contact potential between MgO and BaTiO3. To validate the AFT model, a set of quasi-static experiments will be conducted to test two different operating modes of TENGs, which can be mirrored in the simulations. The first experiment is a micro-scale pull-in/pull-off test in which a pad of single crystal Si (SCSi) will be brought into and out of contact with a dielectric substrate (thermally grown SiO2). The second experiment will mimic the TENG during sliding operation. A SCSi microcantilever will be brought into contact with the dielectric surface and displaced in sliding mode. These experiments will be conducted using a custom, reusable MEMS load cell and an electrometer to monitor the interaction forces and induced charge on the surfaces. To obtain the required displacement resolution of the load cell, a high-speed Michelson interferometer will be used. This allows for higher load cell stiffness to accommodate for surface adhesion effects. The load cell will be calibrated using the well-known technique of hanging masses from the load cell. The relative distance between the interacting surfaces in both experiments will be controlled by a piezo stage with 1 nm resolution. Results from these experiments are to be compared to the AFT model results.
Categorization of Design for Additive Manufacturing Concepts
Authors: Chekurov Sergei 
Published: January 2020

Abstract
Design for AM (DfAM) has become a widely followed research field with practitioners outside of the research community looking for instructions and inspiration on how to leverage the unique capabilities of AM in their products. The research community has responded by producing an abundance of valuable DfAM literature. However, although each individual research article is useful and can answer specific questions, the connection between them can be difficult to fathom due to the lack of a structured overview of DfAM.
This paper proposes a categorization framework to organize the many concepts of DfAM in a structured manner. The framework for the categorization used in this paper is based on a widely used generic product design workflow of Pahl and Beitz that is augmented with concepts from AM literature. The framework is a tool for researchers to position their work in relation to other literature, and it can also be used as a support to achieve novel product designs with AM.
To demonstrate how the framework can be used for guided design, the paper presents every stage of the design process in the context of designing a proof-of-concept heat exchanger that leverages the technical benefits of AM.
Effect of Impingement Surface Velocity on Slot Jet and Slot Jet Reattachment Nozzles’ Flow Field
Authors: Farzad M. , Yagoobi J. 
Published: January 2020

Abstract
Slot jet reattachment (SJR) nozzle is developed in an attempt to enhance heat and mass transfer characteristics while effectively controlling the impingement surface force exerted by the jet flow. In the SJR nozzle, the jet is directed outward from the nozzle exit and it then reattaches on an adjacent surface in its vicinity. The turbulent mixing occurs at the boundaries of the free stream induces secondary flow by mass entrainment and causes the flow to reattach the surface in the form of an oval reattachment at close nozzle to surface spacing [1].
All the previous studies had considered a stationary reattachment surface. This paper, for the first time, investigates the impact of reattachment surface movement on the flow structure of SJR nozzle with three different exit angles of +45°, +20°, and +10°. Specifically, this numerical study is carried out by varying the surface-to-jet velocity ratio (u* = up/ue) from 0 to 1.5 and comparing of flow reattachment flow fields to those of a regular slot jet (SJ) nozzle, where up is the speed of reattachment surface (moving plate) and ue is the jet exit velocity. In this study, jet exit temperature is kept constant at the room temperature of 20°C and all comparisons were performed at the same Reynolds number of 7,900. Additionally, the effect of SJR air exit angle on the peak surface pressure is investigated.
Experimental and Computational Study on the Failure Behavior of Vehicle Battery Modules Subject to Wedge Cutting
Authors: Zhu Feng , Bulla Marian , Lei Jianyin , Du Xianping , Currier Patrick , Sypeck David 
Published: January 2020

Abstract
Lithium-ion (or Li-ion) battery systems have been widely used as the main power source in new generation electric vehicles. Their mechanical performance is very important for vehicle crashworthiness design. In this research, a combined experimental and computational study has been performed to investigate the failure behavior of vehicle battery modules subject to high force wedge cutting. The tests were conducted on a commercial Li-ion battery module at very low speed using a high capacity material testing system. The force and voltage change as a function of cutting depth were measured, and the failure modes were analyzed. A finite element (FE) model based on an explicit FEA solver, was developed to simulate the wedge cutting process. The model predictions demonstrated reasonable agreement. In addition, the influence of several material constants in the failure model on the structural response was also discussed.
Risk Assessment of Escalator Sidewall Entrapment Between the Years 1990 and 2017
Authors: Bress Thomas , Kennedy Eugenia , Sullivan MariAnne , Guttag Mark 
Published: January 2020

Abstract
In previous work, hazards related to escalator sidewall entrapment were examined between the years 1998 and 2017 [1]. This prior analysis included entrapment of the escalator riders’ fingers, hands, toes, or feet. Data were analyzed from the U.S. Consumer Product Safety Commission National Electronic Injury Surveillance System (NEISS) to better understand the trends associated with escalator sidewall entrapment since the introduction of the step/skirt performance index in the 2000 edition of ASME A17.1 Safety Code for Elevators and Escalators. This current effort extends the analysis to include injury data as early as 1990 to discern the trends in sidewall entrapment hazards during the decade prior to the introduction of the step/skirt performance index. The 1990 to 1997 data set was statistically adjusted to account for changes in the sampling frame of the NEISS data set between that period and the 1998 to 2017 data that were analyzed in the previous work [2,3]. This new work analyzes data from the entire time period, 1990 to 2017, to better understand the injury data trends and risks associated with sidewall entrapment. The resulting trends are then compared to the Code modifications introduced to mitigate the hazards of sidewall entrapment.
The statistical grouping analysis used in the previous work is improved and extended in this work. This grouping analysis presents an estimate of the number of sidewall entrapment incidents per day and overall incident percentage for contiguous date ranges covering the years 1990–2017. In all, the work presented herein will allow for a comparison across date ranges for both hand/finger and foot/toe injuries as it relates to modifications to ASME A17.1 such as the addition of the step/skirt performance index.
Control Design Strategies for Semi-Active Suspension System
Authors: Maradey Lazaro Jessica Gissella , Esteban Villegas Helio , Ruiz Brajan , Aldana Andrés 
Published: January 2020

Abstract
Semi-Active Suspension Systems are very important to achieve comfort, ride handling, ground contact of the tyre, road-friendliness and works in a large range of operation. Its use an active dampers and the action of control is very good because of low energy consumption. The force of the damper is regulated according to the operating conditions. Magnetorheological Dampers are commonly used because of his yield resistance, low power, fast response and low cost of production. However, they behave in a non-linear way, following a dynamic of hysteresis so you should give a more sophisticated mathematical treatment. In this paper, we describe the modelling and design of two control strategies for Semi-Active Suspension System. Two control laws will be developed; classical PID and Fuzzy Logic controls law with the simulation and evaluate the stability and performance properties of our controllers in several different scenarios through analysis and simulation simultaneously. The performance of the system is determined by computer simulation in Matlab/ Simulink. The results obtained to compare and prove the effectiveness of these control approaches.
Numerical and Experimental Study of an FSAE Intake Manifold
Authors: Dunn Christian J. , Enriquez Luis G. , Godinez Joel , Moore Matthew T. , Wang Xiuling , Zhou Chenn 
Published: January 2020

Abstract
Formula SAE (FSAE) is an international student engineering competition that allows students to design, manufacture and race a formula-style race car to compete with other universities. This season the Purdue University Northwest (PNW) Formula SAE Team required a means of evaluating potential performance characteristics and optimizing future design concepts for the intake manifold system prior to manufacturing, to reduce the overall time and cost. The air intake system is a critical powertrain system component that requires numerical study and experimentation to validate any meaningful design. Without simulation and testing, an efficient intake may only be designed by chance.
This project focused on replicating the characteristic flow behavior witnessed in the 2017–2018 PNW FSAE intake system using the computational fluid dynamics (CFD) software named STAR-CCM+. A 3D printed test model was manufactured and tested on a flow bench to gather boundary conditions and pressure data from multiple locations within the intake manifold. The physical testing results of the 2017–2018 intake system were with the CFD results in order to validate the simulation models.
Optimization of 3D Printed Elastomeric Nanocomposites for Flexible Strain Sensing Applications
Authors: Abshirini Mohammad , Charara Mohammad , Saha Mrinal C. , Altan M. Cengiz , Liu Yingtao 
Published: January 2020

Abstract
Flexible and sensitive strain sensors can be utilized as wearable sensors and electronic devices in a wide range of applications, such as personal health monitoring, sports performance, and electronic skin. This paper presents the fabrication of a highly flexible and sensitive strain sensor by 3D printing an electrically conductive polydimethylsiloxane (PDMS)/multi-wall carbon nanotube (MWNT) nanocomposite on a PDMS substrate. To maximize the sensor’s gauge factor, the effects of MWNT concentration on the strain sensing function in nanocomposites are evaluated. Critical 3D printing and curing parameters, such as 3D printing nozzle diameter and nanocomposites curing temperature, are explored to achieve the highest piezoresistive response, showing that utilizing a smaller deposition nozzle size and higher curing temperature can result in a higher gauge factor. The optimized 3D printed nanocomposite sensor’s sensitivity is characterized under cyclic tensile loads at different maximum strains and loading rates. A linear piezoresistive response is observed up to 70% strain with an average gauge factor of 12, pointing to the sensor’s potential as a flexible strain sensor. In addition, the sensing function is almost independent of the applied load rate. The fabricated sensors are attached to a glove and used as a wearable sensor by detecting human finger and wrist motion. The results indicate that this 3D printed functional nanocomposite shows promise in a broad range of applications, including wearable and skin mounted sensors.
A Preliminary Study of Active Stabilization for Agricultural Machines Using a Movable Mass
Authors: Bietresato Marco , Belotti Roberto , von Ellenrieder Karl D. , Mazzetto Fabrizio 
Published: January 2020

Abstract
Side overturning is a potentially dangerous phenomenon that can easily happen to agricultural machines because they typically have a high center-of-gravity (CoG) and a very narrow track-width (e.g., tractors operating in orchards). Overturning occurs when the direction of the resultant of the forces acting on the vehicle CoG intercepts the support plane outside of the “support polygon”, defined by taking the footprints of the vehicle wheels as its vertices. Here, we propose the use of a stabilization system that shifts the CoG position to ensure that the resultant force stays within the support polygon. This active stabilization is accomplished by equipping the vehicle with an additional mass that can be moved using an actuator. Using numerical simulations of a four-wheeled narrow-track tractor moving along a trajectory at constant speed, we characterize how the position of the movable mass affects vehicle stability under a quasi-static assumption. The path is a horizontal Euler spiral, having a continuously varying turning radius. The simulations are used to: (i) analyze the sensitivity of four metrics related to the vehicle stability with respect to the additional weight of the moveable mass and the position of the stabilization system, and (ii) find an optimal configuration of the stabilization system that will improve the operational limits of the vehicle.
Modelling and Experimental Validation of a Controllable Energy Harvester for Pressure Regulation
Authors: Ko Youngmok , Yu Shi Miao , Bilton Amy M. 
Published: January 2020

Abstract
A pico-scale Francis turbine (or energy harvester) was designed, fabricated and tested for pressure regulation and power generation application. The prototype energy harvester contains pivotable guide vanes and a controllable load to change the runner speed. This allows the simultaneous variation of the pressure drop and the output power. A computational fluid dynamics (CFD) model of the turbine was developed in ANSYS CFX 18.1 to evaluate the turbine’s sensitivity to geometric parameters such as the clearance gap size of the guide vane and its modularity. In conjunction to the CFD model, the electric generator’s characteristics were used to predict the turbine performance at varying guide vane angles. The turbine was prototyped and tested using a custom-built experimental set-up. The pico-scale turbine, with a runner diameter of 1.42 inches, was able to output up to 100 W of electrical power at its rated flowrate of 29 GPM. By varying the guide vane angles, the pressure drop and the hydraulic efficiency varied between 3–22 psi and up to 60% respectively. When validated against the experimental results, the CFD model showed a good agreement despite its low computational cost. The energy harvester’s initial characteristics demonstrate its potential as a game changer in the control valve market.
Mechanical Response and Incomplete Filling in Compression Molding With Microscale Double-Punch Sets
Authors: Zhang Bin , Dodaran M. , Shao S. , Meng W. J. 
Published: January 2020

Abstract
Forming nano-/micro-scale surface patterns on metal surfaces by direct compression molding is an important means for achieving small scale surface features with potential usage in wide ranging technological applications. Geometric fidelity of molded features and the corresponding molding response are of critical importance in determining the usefulness of the molding replication technique. In this paper, two series of microscale punches made of tool steels were fabricated using Ga+ focused ion beam (FIB). In one series, the punch consists of a single protruding rectangular strip of different width, w (dubbed the “single punch”). In the other series, the punch consists of two rectangular strips of identical dimensions separated by a spacing in between, s (dubbed the “double punch”). These so-fabricated punches were used to mold elemental single crystal Al. The mechanical response during compression molding was measured and analyzed. For the double-punch experiments, measured characteristic molding pressure exhibited a significant dependence on the spacing to punch width ratio, λ = s/w, as well as a significant dependence on s when λ was fixed. The molded features were examined and the phenomenon of incomplete filling was observed to occur at λ &lt; 0.5.
Microstructural Hyperelastic Characterization of Brain White Matter in Tension
Authors: Ramzanpour Mohammadreza , Hosseini-Farid Mohammad , Ziejewski Mariusz , Karami Ghodrat 
Published: January 2020

Abstract
Axons as microstructural constituent elements of brain white matter are highly oriented in extracellular matrix (ECM) in one direction. Therefore, it is possible to model the human brain white matter as a unidirectional fibrous composite material. A micromechanical finite element model of the brain white matter is developed to indirectly measure the brain white matter constituents’ properties including axon and ECM under tensile loading. Experimental tension test on corona radiata conducted by Budday et al. 2017 [1] is used in this study and one-term Ogden hyperelastic constitutive model is applied to characterize its behavior. By the application of genetic algorithm (GA) as a black box optimization method, the Ogden hyperelastic parameters of axon and ECM minimizing the error between numerical finite element simulation and experimental results are measured. Inverse analysis is conducted on the resultant optimized parameters shows high correlation of coefficient (&gt;99%) between the numerical and experimental data which verifies the accuracy of the optimization procedure. The volume fraction of axons in porcine brain white matter is taken to be 52.7% and the stiffness ratio of axon to ECM is perceived to be 3.0. As these values are not accurately known for human brain white matter, we study the material properties of axon and ECM for different stiffness ratio and axon volume fraction values. The results of this study helps to better understand the micromechanical structure of the brain and micro-level injuries such as diffuse axonal injury.