bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Analysis of Venturi-Tube Behavior in Wet Gas Conditions
Authors: Mehlum Olav , Hundseid Øyvind , Bakken Lars E. 
Published: February 2021

Abstract
Subsea wet gas compressors have been successfully in operation for approximately 5 years. Their use has proven to increase the recovery by approximately 10% and achieve a reliability up to 98%. Further developed and operation of subsea wet gas compression require detailed knowledge of compressor operability and how shift in operational conditions affect the compressor system. The compressors ability to handle wet gas is documented in detail for a gas volume fraction limited down to 0.90. The 4–5 last year of operation proves the wet gas concepts capability. As years pass by, well pressure and production rate declines which causes the compressor operation point to shift towards the high head and low flow (surge) area of the characteristics. In addition, compressor inlet transients increase due to pipe surge (slugs), requiring a robust control system to prevent instabilities, e.g. compressor surge. It is therefore vital to understand how the compressor inlet flow device behaves at different wet operation conditions.
The article documents how a standard dry gas venturi tube behave at different wet gas operation conditions. The venturi is designed according to ISO5167-4 for dry gas conditions and is tested at the low-pressure air water compressor test rig at NTNU. The primary objective of the work has been to visualize the wet flow regime through the transparent venturi tube and to document the wet gas flow rate measurements by means of single-phase meters. The venturi tube is tested in a GMF range from 1 to 0.83 at an air volume flow rate of 1.3m3/s.
An Energy Frame of Reference to Assess Vehicle’s Physical Externalities
Authors: Otremba Frank , Romero Navarrete José A. , Lozano Guzmán Alejandro A. 
Published: February 2021

Abstract
Externalities of the road transportation are multidimensional in nature and involve the road-vehicle interaction under different environmental conditions. Estimating the pavement and vehicle damage potentials as a function of the conditions under which such interaction takes place, is important to avoid accelerated or catastrophic damages in these systems. Such an assessing is crucial from the perspective of pricing the effects of the vehicle on the infrastructure and vice versa. The existing models for pricing such interaction, critically depends on gross average statistical models. In this paper, it is proposed a deterministic approach to realize such an assessment, based upon validated approaches for the pavement damage. The simulation scheme considers different degrees-of-freedom vehicle models, and a discrete asphalt pavement, that make possible the simulation of massive traffic situations on realistic road lengths.
Molecular Dynamics Study on Interfacial Fracture of Aluminum Alloy and Epoxy Resin Adhesive Subjected to Cyclic Loading
Authors: Kanamori Kohei , Kimoto Yoshikatsu , Yonezu Akio 
Published: February 2021

Abstract
Direct bonding of metal-resin plays a critical role in jointing of dissimilar materials and the adhesion strength is known to be dependent on strain rate (loading rate) due to the strain rate sensitivity of polymeric resin. This study evaluated adhesion strength and adhesion durability against repetitive loading for the interface between aluminum alloy and epoxy resin. For experiment, a pulsed YAG laser was used to generate strong elastic waves, resulting in interfacial fracture. This method is called Laser Shock Adhesion Test (LaSAT), which enables us to evaluate impact strength of interfacial fracture. This study prepared two types of specimens with different curing temperature (20°C and 100°C). It is found that the specimen with higher temperature curing shows larger adhesion strength. Subsequently, repetitive LaSAT experiments (cyclic loading tests) were conducted to evaluate adhesion durability. This reveals that adhesion strength showed cyclic fatigue characteristics and higher curing temperature improves fatigue strength. To elucidate this mechanism at molecular level, molecular dynamics (MD) simulation was conducted for the interfacial material with epoxy resin. This study created all-atomistic model of Al2O3/epoxy resin interface, and repetitive tensile deformation was applied until delamination. It is found that the number of loading cycles to delamination was increased when the applied tensile stress was lower. It is also found that the 400K curing model showed larger adhesion strength than that of the 300K curing model. This trend is very similar with the results of LaSAT experiments. Our comprehensive study with LaSAT experiments and MD simulations evaluates adhesion strength of Al/epoxy interface and reveals its fracture mechanism.
Optimal Extrusion Die Design for Production of Polymer Tensile Test Specimen
Authors: Andrade Sebastián Acosta , Rigail-Cedeño Andrés , Tapia-Bastidas Clotario V. , Castillo-Orozco Eduardo 
Published: February 2021

Abstract
This work aims to present the design of an extrusion die for the production of polymeric tensile test specimens. Computational Fluid Dynamics is used during the optimization process to minimize the overall pressure drop across the die, achieve uniform exit velocity, low energy consumption, high throughput, and excellent properties of the extruded specimens. A three-dimensional incompressible viscous flow is considered and the Cross model is employed for taking into account the non-Newtonian behavior of the flow. Several geometries are analyzed before devising an optimum shape. The final design includes, in the beginning, a conical flow profile and then it gradually transitions into the rectangular cross-section of the slab. The die land is an elongated flow restriction channel of smaller cross-section, where the material experiences gradually-decreasing pressures along the length of the land and finally converging the molten polymer into a melt laminate at the exit.
Crack Deflection Near a Ply Interface in a Composite Laminate
Authors: Zhuang Linqi , Talreja Ramesh , Maragoni Lucio 
Published: February 2021

Abstract
The deflection of a matrix crack near 0°/90° interface in a cross-ply laminate was studied numerically. In the finite element (FE) model, an initial matrix crack was introduced in the 90° layers away from the 0°/90° interface. The initial matrix crack could be initiated either at the middle of 90° layer or at one side of 0°/90° interface. The 0° layers and a part of the initial matrix crack were modeled using homogenized layer properties to simplify the model. The nonuniformly distributed fibers were modeled explicitly close to the 0°/90° interface in order to study the influence of this nonuniformity on the crack deflection process. The Energy Release Rate (ERR) of debond crack tip was calculated using Virtual Crack Closure Technique (VCCT) to study the debond growth. Maximum principal stress was then adopted to access the debond crack kinking qualitatively. It’s found that when a macro-size matrix crack forms and propagate towards ply interface, the subsequent debonding and debond cracking process in nearby intact fiber shows some distinct differences compared to the same processes at single isolated fiber without considering the interaction with nearby debonded fiber and existing matrix crack. Meanwhile, present analysis shows clear influence of microstructures on the crack deflection process by affecting the fiber/matrix debonding and debond kinking processes.
Composite Core Cross Tube Crushing Analysis
Authors: Jenson Sean , Ali Muhammad , Alam Khairul 
Published: February 2021

Abstract
Thin walled axial members are typically used in automobiles’ side and front chassis to improve crashworthiness of vehicles. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of inclusion of functionally graded cellular structures in thin walled members under axial compressive loading. A compact functionally graded composite cellular core was introduced inside a cross tube with side length and wall thickness of 25.4 mm and 3.048 mm, respectively. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were evaluated. The results showed that the inclusion of composite graded cellular structure increased the energy absorption capacity of the cross tube significantly. The composite graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the cross tube thus delaying local tube wall collapse and promoting large localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that were observed in the empty cross tube under axial compressive loading. The variation in deformation mode resulted in enhanced stiffness of the composite structure, and therefore, high energy absorption by the structure. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.
Ballistic Performance of Sandwich Composite Armor System
Authors: Alam Shah , Shakar Samhith 
Published: February 2021

Abstract
This study focused on the design, modelling and the analysis of the dynamic response of composite armor system, constructed with Kevlar 29 as front skin, Alumina-ceramic filled in x shaped corrugated structure as core and bottom skin Kevlar 29 and T800S, in terms of residual velocity, energy absorption capacity and limiting velocity. The core cell size, height, thickness, skin thickness, etc., will be varied to get their influence on the impact resistance.
The design parameter will be investigated for the sandwich composite armor with various configurations and stacking sequence of Alumina Ceramics, Kevlar 29 and T800S. The sandwich typically consists of front plate, core and backing plate, which will be impacted at different velocities starting at 100m/s till significant armor penetration. The ballistic limit velocity (V50) will be determined from the analysis. The non-linear explicit dynamic analysis and simulation results computed using the software ABAQUS will be validated by experiment. From the data obtained it can be suggested which composite armor has improved impact resistance and performance.
Evaluation of Crushing Response of Limited Bonding of a Composite Core With a Cross Tube
Authors: Jenson Sean , Ali Muhammad , Alam Khairul 
Published: February 2021

Abstract
Rectangular and round tubular structures are typically used in a vehicles’ front structure to increase the energy absorption capacity in the event of an accident. There is significant interest in lighter structures for improving automobiles’ fuel efficiency with the challenge of maintaining or preferably exceeding the energy absorption properties of the structure. The structural members are designed to take on the challenge of absorbing maximum amount of energy in a relatively short period of time, while also maintaining reactive forces below damaging levels as they undergo progressive deformation under axial loading. The type of deformation mode is critical as it defines the overall configuration of force-displacement curve. There are different types of deformation modes for cross tube under axial loading. Likewise, cellular structures exhibit distinct deformation modes under in-plane loading. The work presented here investigates the effects of bonding of composite cellular core structure on deformation modes of cross tubes under axial loading. The numerical simulations were performed in ABAQUS finite element software. Four cases were considered for analysis. The first case did not contain core bonding. The second case consisted of 3 bonding sites. In the third case, 5 bonding zones were defined and in the final case, 7 bonding sites were assigned. Bonding of the composite core resulted in an increase of up to 39.2% energy absorption as compared to the unbonded case. The results show discrete bonding of composite cellular core with the tube has significant effect on progressive deformation of tubes and therefore, presents an opportunity to re-configure force-displacement curve for improved protection of automobile structures under impact loading.
Initial Testing and Constitutive Modeling of Cellular Rubber Subjected to Large Strains and High Strain Rates
Authors: Bieler James A. , Davis Brad G. 
Published: February 2021

Abstract
In order to allow for the numerical modeling of impacts for the design of live fire facilities commonly used by military and law enforcement personnel against next generation and environmentally friendly ammunition currently in development, constitutive models for novel target materials must be developed. Many existing facilities are constructed from AR500 steel, coupled with a layer of cellular rubber to reduce impact velocities and contain projectile fragments. High strain rate models, such as the commonly used Johnson-Cook constitutive model, are widely available to characterize AR500 steel, but calibrated models do not currently exist to characterize the cellular rubber. This project seeks to address this shortfall and provide a suitable material model for designers of these facilities in order to ensure the safety of users and the public. Appropriate constitutive models that account for the large strain, high strain rates, and temperature effects experienced during ballistic events and the porosity of the material were researched and a plan developed for future materials testing. Three suitable models were selected for further analysis — A Non-Linear Elastic Model described by Johnson in his work with polyurethane coupled with a Mie-Gruneisen equation of state to account for the porosity of the material, an Osborn-Hull model developed for use with crushable solids, and the Holmquist-Johnson-Cook Model commonly used for cementitious materials.
Education and Workforce Development Programs in the Center for Advanced Automotive Technology
Authors: Liao Y. Gene , Yeh Chih-Ping , Petrosky Joseph , Hutchison Donald 
Published: February 2021

Abstract
The automotive industry is currently experiencing a revolutionary technological transformation including electrification, connectivity, automated/autonomous, lightweighting, and sustainability. This paper presents the education and workforce development programs developed and delivered by Wayne State University and Macomb Community College partnership in meeting industry needs for future workforce in advanced automotive technology. Through funding from the National Science Foundation, a Center for Advanced Automotive Technology (CAAT) was established as an Advanced Technological Education center to support the partnering work, developing and leading systemic curricula reforms. The center worked with industry partners identifying curriculum gaps and provided professional development for teachers to fill those gaps. CAAT also supported new automotive technology university/college programs through its seed funding program which funded others to create, implement, and share new curricula. The center is a preeminent resource for educating engineers and technicians in advanced automotive technology as all materials that were developed in partnership with CAAT were reviewed by industry experts and offered as a free resource through website. CAAT continues its tasks supporting the United States in its efforts to build and maintain a competent workforce ready to use the skills of the 21st century to move industries ahead.
Nonlinear Fluid-Elastic Behavior of a Flapping Wing With Low-Order Chord-Wise Flexibility
Authors: Majumdar Dipanjan , Bose Chandan , Sarkar Sunetra 
Published: February 2021

Abstract
The present study attempts to capture the fluid-structure interaction dynamics of a chord-wise flexible flapping wing system using a limited mode structural model coupled with a high-fidelity Navier-Stokes (N-S) solver. The wing is modeled as two elliptic rigid foils connected by a non-linear torsional spring that incorporates the chord-wise bending stiffness. The front link is subjected to an active pitching-plunging motion while the rear link undergoes flow-induced passive oscillation. The structural governing equation for the rear link takes the form of a Duffing equation subjected to base excitation and external aerodynamic forcing. The aerodynamic loads on the foil are computed using a discrete forcing Immersed Boundary Method based in-house N-S solver which is coupled with the structural solver by a staggered weak coupling strategy. A bifurcation study is performed considering the free-stream velocity as the control parameter, in the presence of both structural and aerodynamic non-linearities. A dynamical transition in the unsteady flow-field from a periodic reverse-Kármán wake to an aperiodic wake is observed as the flow parameters are varied. The same transition is also reflected in the passive oscillation of the rear foil when analyzed with tools from the dynamical systems theory.
Constitutive Modeling and Initial Validation of Cellular Concrete Subjected to Large Strains and High Strain Rates
Authors: Davis Brad G. , Dequenne Jared A. 
Published: February 2021

Abstract
The development of lead-free small caliber weapon systems has inadvertently resulted in rounds with more material penetration capabilities. The increased penetration may mean that existing live-fire facilities will no longer be adequate for the training and certification of military and law enforcement personnel. Constraints on training in many live-fire shoot house facilities are already in place, with some allowing only single round impact during training. With no existing constitutive model for the cellular concrete commonly used in these facilities, it is not currently possible to analyze existing facilities or design new facilities against the most recent generation of ammunition currently being fielded. This project utilizes unconfined compression, uniaxial tension, triaxial confinement, and uniaxial strain from the US Army Corps of Engineers Engineer Research and Development Center and Sandia National Laboratory to characterize cellular concrete using a Holmquist-Johnson-Cook Concrete model for use in numerical simulations. This model is then initially validated using data from existing single projectile impact experiments against a similar material, showing results with reasonable accuracy. Additional experiments to fully validate the proposed model are discussed.
This model provides the facility owner a potential tool to validate the safety of their facility against new projectiles and provides the designer of new facilities a tool for optimizing future configurations using these materials.
Elastic-Viscoplastic Mechanics of Lithium in a Standard Dry Room
Authors: Dienemann Lara L. , Saigal Anil , Zimmerman Michael A. 
Published: February 2021

Abstract
In electrochemical-mechanical modeling of solid-state batteries, there is a lack of understanding of the mechanical parameters and mode of deformation of lithium metal. Understanding these characteristics is crucial for predicting the propagation of lithium dendrites through the electrolyte — a key element of battery safety. Past theories have assumed linear elastic as well as elastic-plastic deformation of lithium. However, recent experiments show that the primary mode of deformation is creep. This study replicates the temperature dependent mechanical experiments but inside an industrial dry room, where battery cells are manufactured at high volume. Furthermore, this work conducts time dependent studies — also inside the dry room — to gain insight of the large deformation theories of lithium metal. The results confirm the activation energy, which dictates the creep mechanism, is correlated to core diffusion rather than lattice diffusion.
Predicting the Combustion Phasing of a Natural Gas Spark Ignition Engine Using the K-Nearest Neighbors Algorithm
Authors: Liu Jinlong , Ulishney Christopher , Dumitrescu Cosmin E. 
Published: February 2021

Abstract
Location of the peak cylinder pressure and the crank angle associated with half of the energy releases during the combustion process are generally used to define the engine combustion phasing and control the engine efficiency. To accelerate the optimization of a natural gas spark ignition internal combustion engine, this study proposes a black box modeling approach that will reduce the experimental or computational time needed to estimate the high efficient operating conditions at a particular engine speed and load via combustion phasing information. Specifically, a k-nearest neighbors (KNN) algorithm applied key engine operating variables such as the spark timing, air-fuel ratio, and engine speed as inputs to predict combustion phasing parameters such as the crank angles associated with peak cylinder pressure and 50% energy release. After training the correlative model, the selected engine variables produced acceptable errors for most operating conditions investigated. The results showed that the KNN algorithm predicted much better the location of the peak pressure than the location of the 50% energy release, as evidenced by the larger R2 values and smaller prediction errors. In addition, the regression model built in this study produced larger errors in the sparse-distributed region. Therefore, a more uniformly distributed training dataset is suggested for KNN algorithm, at least for the situations investigated in this research.
Demonstrating the Generation of Bond Graphs From 3D Assemblies
Authors: Alicchio Corey J. , Vitiello Justin S. , Radhakrishnan Pradeep 
Published: February 2021

Abstract
The bond graph method provides a generic and simple way to compute differential equations and dynamic responses for complex mechatronic systems. This paper will illustrate the process of automatically generating bond graphs from 3D CAD assemblies of gear-trains. Using appropriate CAD application programming interfaces (APIs), information on parts and mates within an existing assembly is extracted. The extracted information is stored as an identity graph, which also stores all geometry and mass related information of every part. Grammar rules are then used to transform the identity graph to a system graph, which is then converted to bond graph using an existing bond graph generation program. The paper will discuss the process, challenges and planned future work.
Radial Wall Jet Flow Over Sigmoidal Surfaces
Authors: Pease Leonard F. , Minette Michael J. , Bamberger Judith Ann 
Published: February 2021

Abstract
Radial wall jet flows across flat smooth surfaces have been studied for decades. These studies show that the radial velocity of these jets decays inversely with distance from the nozzle with modest contribution from friction (Poreh, et al., 1967; Rajaratnam, 1976). However, the extent to which flat surface results apply to curved surfaces remains unclear. In this paper we explore the influence of settled particle bed slope on radial wall jet velocity profiles. Jet flows over particle beds often introduce curvature in the particle bed profile, but the influence of the developed curvature on the velocity profile has not been explored. We model the step change in thickness as a sigmoidal curve of variable steepness and use conservation of momentum to evaluate the velocity profile for steady fixed beds. We find that surface curvature has a significant influence on the velocity decay coefficients, provided there is a slip velocity in the vicinity of the particle bed interface, which is strictly true for particle surfaces. We show that the velocity profile attenuates because of curvature. Indeed, conservation of momentum predicts conditions where the forward momentum of the flow is directed completely upward. The solution identifies two new dimensionless groups that determine whether a curved surface is sufficient to block radial flow and force flow vertically.