bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crashworthiness Performance of Space Frame Aluminum Structure in NCAP’s 35 MPH Full Frontal
Authors: Baccouche Mohamed Ridha , Mahmood Hikmat F. , Shivakumar Arkalgud K. , Jawad Saad A. 
Published: December 2021

Abstract
The quest for lighter crash energy absorbing automotive structures has increased the use, parallel with other materials, of the 5xxx sheet and 6xxx extruded aluminum structures. These aluminum structures, when properly designed and joined, are able to demonstrate a very high crash energy absorbing capability.
This paper summarizes the CAE and development work performed in the design of the front end structure of a four door C-class space frame aluminum vehicle. Component and system CAE modeling of the front end were conducted under NCAP’s 35 mph full frontal impact using rigid body dynamic, nonlinear beam finite element and stability codes. Component loads versus crash distances and system deceleration versus time responses were computed.
A 3D spring mass model was built for the front end structure using the rigid body and finite element code MADYMO. Spring characteristics for each component, derived from test data and component CAE models, were input into the MADYMO model. The deceleration-time response generated by the MADYMO model was used as input for the sled testing. The effects of four parameters were studied and discussed in this paper. These parameters are the steering column angle, IP, Pyro Buckle Pretensioner and airbag vent size. Dummy HIC; chest deceleration; neck shear, tension, compression, flexion and extension; femur load, pelvis acceleration and displacement; retractor load; shoulder belt load; lap belt load and other injury numbers, measured from sled test, are summarized and discussed in this paper.
Crashworthiness of Aluminum Structures
Authors: Warren A. S. , Wheeler M. J. 
Published: December 2021

Abstract
There is a growing recognition by the auto makers of the benefits of aluminum for vehicle structures. While there is now no doubt that the structural demands of vehicles can be met with aluminum, it is less well appreciated that such structures can also be designed to provide a high level of crashworthiness.
This paper summarizes the basic work that has been carried out to demonstrate and quantify the behavior and energy absorption of aluminum vehicle structures under impact collapse conditions. Aluminum, like steel, collapses under high load conditions by folding and the resulting work of deformation absorbs the vehicle’s kinetic energy. It follows that most of the general rules for designing crashworthy structures in steel, in terms of ensuring progressive collapse, avoiding premature bending failures, and transferring load as the collapse event proceeds, apply equally well to aluminum structures. There are, however, differences from steel due to the greater thickness of aluminum material used. This increases resistance to local buckling, and results in larger volumes of the material becoming involved in the energy absorbing collapse events.
There are other material characteristics that have a bearing on developing crashworthy aluminum structures, and the paper covers the more significant material and related design guidelines that should be followed in the development of the main energy absorbing structural members in vehicle structures. Finally, reference is made to results from NHTSA’s NCAP program for appraising the crashworthiness of new vehicles. These have demonstrated in a very practical way the excellent crashworthiness of vehicles with well designed aluminum structures.
A Comparison of Mathematical Neck Models for Rear Impact Occupant Simulation
Authors: Marshall Rob , Altamore Paul , Wu Wei-Pin , Griffioen Jan A. 
Published: December 2021

Abstract
Occupant injury in automobile rear-end collisions is becoming one of the most costly and aggravating traffic safety problems. Designing seat and head restraints to help limit injury associated with rear-end impact can become more efficient by using new mathematical modeling techniques. Using the facet surface modeling technique in MADYMO a model is developed that captures the interaction between occupants and seat/head restraints with a high degree of geometric accuracy while maintaining efficient computer run times. One such model is validated using a prototype seat/head restraint and the TRID (TNO Rear Impact Dummy), both using facet surface techniques. From this model a study is done to compare the results of the TRID model and the results from a Hybrid III model with the results from a Human neck model. This study is performed in several different head restraint positions.
Micromechanics Based Composite Material Model for Impact and Crashworthiness Explicit Finite Element Simulation
Authors: Tabiei Ala 
Published: December 2021

Abstract
A micro-mechanical model is developed for laminated composite materials and implemented in the explicit finite element method. The objective of this study is to get an accurate and simple micro-model, which can be used in the displacement-based explicit finite element packages. The micro-mechanical model implemented in the explicit finite element code can be used for simulating the behavior of composite structures under various loads such as impact and crash. The stress-strain relation for the micro-model is derived for shell element. As a demonstration case of the developed micro-model a finite element model of Graphite/Epoxy tube structure is developed and simulated under axial crash.
An Optimized Methodology for the Creation of Highly Detailed Finite Element Models of Road Vehicles for Use in Crash Simulation
Authors: Monclus-Gonzalez Jesus , Kan Cing-Dao , Bedewi Nabih E. 
Published: December 2021

Abstract
This paper explains the improvements introduced in the existing methodology for the development of Finite Element (FE) models of road vehicles for crashworthiness purposes. The improvements were implemented during the creation of a highly detailed FE model of the frontal section of a 1997 Dodge Grand Caravan. Lessons learned during the reverse engineering are presented, with emphasis on the definition of the global and local coordinate systems. Detailed information regarding the time invested in the geometry discretization phase is offered. Also, the main aspects of the modeling phases are summarily explained. The pre-processor used for the development of this model was MSC/PATRAN, while the finite element solver was LS-DYNA. The resulting FE model of the frontal section of the 1997 Dodge Grand Caravan includes 334 parts, 196,447 nodes, 189,785 elements and 3,238 connections. Finally, the benefits of the improved methodology are discussed and several examples of quality achievements are commented.
Prediction of Heat Transfer in Turbulent Decaying Swirling Flow
Authors: Uskaner Yusuf A. 
Published: December 2021

Abstract
This paper presents an aproach for the prediction of heat transfer augmentation in decaying swirling flow in a pipe by making an analogy between the increase in friction factor due to swirl and increase in heat transfer due to swirl. The proposed method can be used to predict heat transfer for decaying swirling flow in smooth and rough pipes which can be applied to different swirl generators based on the known inlet swirl conditions. An experimental study is performed regarding the swirling flow of air in smooth and rough pipes. The experimental study covered only the fluid dynamics of swirling flow. No heat transfer experiments were done. It is determined experimentally that in swirling flows degree of swirl decays continuously along the smooth and rough pipes and the total loss factor is the sum of friction factor for non-swirling flow and the swirl loss factor. Swirl loss factor is found to be a function of the degree of swirl and pipe relative roughness. Using the relations obtained experimentally for the variation of swirl strength and loss factor along the pipe, an equation is proposed to be used for the prediction of heat transfer in turbulent decaying swirling flows.
Improved Correlation for Natural Convection Heat Transfer From Inclined Cylinders Having Different Emissivities
Authors: Stewart Jeffrey C. , Janna William S. 
Published: December 2021

Abstract
The purpose of this study was to develop an improved correlation for natural convection heat transfer from inclined cylinders having different emissivities. The angle of cylinder inclination varied from horizontal to vertical in 15° increments. The heat transfer coefficient was obtained experimentally with the cylinder in a state of constant heat flux. Three surface finishes were used in the experiment, which consisted of polished copper, black paint, and aluminum paint. The heat transfer coefficients in all cases varied from 1.21 to 1.65 BTU/(hr·ft2·R) [6.87 to 9.37 W/(m2·K)]. Rayeigh numbers for all experiments varied from 1.31 × 103 to 2.23 × 103. The heat transfer coefficient decreased for each cylinder with an increasing angle of inclination (from horizontal to vertical). The goal of this study was to produce Nusselt-Rayleigh number correlations for each cylinder, and then ultimately produce a single equation that can be applied for all emissivities. The Rayleigh number included a geometry term to account for the inclination of the cylinder. The form of the equation that best represented the data was a power law equation.
Effect of Transversal Aspect Ratio on Natural Convection Inside Open-Ended Cavities With Uniformly Heated Horizontal Walls
Authors: Manca Oronzio , Morrone Biagio , Nardini Sergio 
Published: December 2021

Abstract
An experimental analysis of effects of transversal aspect ratio on air natural convection between horizontal parallel plates, with the lower plate heated, was carried out by means of visualization of flow and air temperature measurement. The distance between the plates, b, in the experiments was 40.0 mm and the width of the plates, W, was 100, 200 and 460 mm. The corresponding transversal aspect ratios, W/b, were 2.5, 5.0 and 11.5. The main flow pattern resembles a C shape (C-loop) in the longitudinal section. In fact, the flow penetrates inside the cavity close to the leading edge of the lower plate and exits from the upper part, by reversing its motion between the plates. The flow visualization and the temperature time records indicate that the lateral walls have significant impact on the secondary flows. As a matter of fact, when the transversal aspect ratio decreases the temperature fluctuations at any location became more regular. The average temperature values, instead do not present marked dependence on W/b.
Estimating the Maximum Splat Diameter of a Solidifying Droplet
Authors: Hadjiconstantinou Nicolas G. 
Published: December 2021

Abstract
We present a simple analytical model for the estimation of the maximum splat diameter of an impacting droplet on a subcooled target. This work is an extension of the isothermal model of Pasandideh-Fard et al. (1996). The model uses an energy conservation argument, applied between the initial and final drop configurations, to approximately capture the dynamics of spreading. The effects of viscous dissipation, surface tension, and contact angle are taken into account. Tests against limited experimental data at high Reynolds and Weber numbers indicate that an accuracy of the order of 5% is achieved with no adjustable parameters required. Agreement with experimental data in the limit We → ∞ is also very good. We additionally propose a simple model for the estimation of the thickness of the freezing layer developed at the droplet-substrate contact during droplet spreading. This model accounts for the effect of thermal contact resistance and its predictions compare favorably with experimental data.
Drag Reduction on Microscale Concave-Convex Surface
Authors: Hasegawa Masato , Nariai Hideki , Kaneko Kazufumi , Maki Hiroshi , Yabe Akira , Matsumoto Sohei 
Published: December 2021

Abstract
Experimental work on the drag reduction phenomena on the highly water-repellent wall has been done. Fabricated surface, which has concave-convex structure of micrometer scale, was implemented as the tested plate in cone-plate viscometer. The surfaces exhibited the increase of the frictional torque with the projection height of 5 μm. The case of 1.15μm did not show the increase of flow resistance while the result of case of 1.4μm depended on Reynolds number. Another set of the ultra small-scale concave-convex surface was made on 4 inches silicon wafer by lithography and RIE (Reactive Ion Etching), with hydrophobic coating. The surface with high contact angle of 150 degrees for water droplet of 1.4mm diameter showed the drag reduction by maximally 9 percent at Reynolds number around 6.5 × 104. The hydrophobic surface exhibited the decrease in friction coefficient by 6 percent even when it was smooth. PTFE membrane filters have also been tested since the filters can trap gas or bubble on surface, considering that the existence of gas layer at solid liquid interlace is necessary for slip at the boundary to be occurred. The filters showed reduction in friction coefficient, maximally about 6 percent. The rate of the reduction slightly changes related to the size of pores in the filters.
Thermal Conductivity of Nano-Porous Bismuth Thin Films for Thermoelectric Applications
Authors: Song David W. , Shen Wei-Ning , Zeng Taofang , Liu Weili , Chen Gang , Dunn Bruce , Moore Caroline D. , Goorsky Mark S. , Radetic Tamara , Gronsky Ronald 
Published: December 2021

Abstract
Good thermoelectric materials require a small thermal conductivity while maintaining a high electrical conductivity and Seebeck coefficient. Nano-porous systems provide one possible route of increasing the thermoelectric figure-of-merit by disturbing phonon transport more than electron transport. In this work, the temperature dependent thermal conductivity of nano-porous bismuth thin films was measured. Thin Bi films of various porosity and thickness were deposited by metal-organic deposition onto Si substrates. The thermal conductivity of Bi films was measured using a differential 3-ω method, in which the temperature rise across a Bi film was experimentally measured and used to calculate its thermal conductivity. Experimental results show an order-of-magnitude reduction in the porous Bi thin film thermal conductivity due to nano-pores compared to non-porous films. The drastic reduction in thermal conductivity cannot be explained by available models on the thermal conductivity of porous media.
Two-Phase Transport in Proton Exchange Membrane Fuel Cells
Authors: Wang C. Y. , Wang Z. H. , Pan Y. 
Published: December 2021

Abstract
Proton exchange membrane (PEM) fuel cells have emerged, in the last decade, as a viable technology for power generation and energy conversion. Fuel cell (FC) engines for vehicular applications possess many attributes such as high fuel efficiency, low emission, quiet and low temperature operation, and modularity. An important phenomenon limiting fuel cell performance is the two-phase flow and transport of fuel and oxidant from flow channels to reaction sites. In this paper a mathematical model is presented to study the two-phase flow dynamics, multi-component transport and electrochemical kinetics in the air cathode, the most important component of the hydrogen PEM fuel cell. A major feature of the present model is that it unifies single- and two-phase analyses for low and high current densities, respectively, and it is capable of predicting the threshold current density corresponding to the onset of liquid water formation in the air cathode. A numerical study based on the finite volume method is then undertaken to calculate the detailed distributions of local current density, oxygen concentration, water vapor concentration and liquid water saturation as well as their effects on the cell polarization curve. The simulated polarization curve and predicted threshold current density corresponding to the onset of liquid water formation for a single-channel, 5cm2 fuel cell compare favorably with experimental results. Quantitative comparisons with experiments presently being conducted at our laboratory will be reported in a forthcoming paper.
Models for Annular Film Condensation in Vertical Tubes With Vapour Downflow: A Critical Review
Authors: Briggs Adrian 
Published: December 2021

Abstract
Various approaches to the problem of modelling annular film condensation in a vertical tube with downflow are analysed. Laminar and turbulent film models are discussed and applied to intube condensation. The results are compared to several empirical and semi-empirical models for intube condensation.
Heat and Mass Transfer in Granular Potash Fertilizer With a Surface Dissolution Reaction
Authors: Peng Shi-Wen , Besant Robert W. , Strathdee Graeme 
Published: December 2021

Abstract
Potash is a widely used granular fertilizer and when exposed to high humidities it readily adsorbs water forming a liquid electrolyte solution on each particle. Heat and mass transfer due to air flow through granular potash beds is studied experimentally and numerically. A one dimensional experimental set-up is used to measure the temperature and air humidity response and mass gain of a potash bed subject to a step change in air flow. A porous media mathematical model is developed to predict the transient temperature and moisture content distributions. The transport processes are modelled as non-equilibrium heat and mass transfer between the porous solid and air flow gaseous phases. The state of the surface electrolyte solution is modelled by the thermodynamics of electrolyte solutions. Experimental and numerical results shows that when there is a strong surface heat source due to phase change, especially near the entrance region, non-equilibrium internal moisture and heat transfer processes exist. The temperature difference between potash granules and the air flowing through the potash bed is significant.
Heat Transfer Characteristics in Convective Melting of a Solid Particle in a Fluid
Authors: Hao Y. L. , Tao Y.-X. 
Published: December 2021

Abstract
An experimental investigation is conducted to study the heat transfer characteristics in convective melting of a solid particle in a flowing fluid. An ice sphere is used to represent the solid particle. This experiment serves as a basis for further improvement of numerical modeling on the convective melting of a single particle or a packed bed. The process of convective melting of an ice sphere in a horizontal, flowing water is visualized by using a digital video camera under controlled flow rate and supply water temperature. From the digital video images the shape changes of the ice sphere are measured, and the melting rate and heat transfer rate between fluid and particle is determined. A shape factor that indicates shape variation of particle in the melting process is defined. An empirical correlation that can be used to calculate the liquid-solid heat transfer coefficient in convective melting of a solid particle in a flowing fluid was obtained.
Three-Dimensional Numerical Simulation of Convective Melting of Solid Particles in a Fluid
Authors: Hao Y. L. , Tao Y.-X. 
Published: December 2021

Abstract
A physical model of two-phase flow and heat-mass transfer with the phase changes based on the theory of interacting continua is proposed. All terms in the conservation equations are analyzed and the constitutive equations are presented. A closed set of governing equations describing the convective melting of solid particles in a fluid is obtained. The numerical method is developed for the solution of velocity, temperature, and volume fraction of solid phase for the three-dimensional melting in a rectangular cross-section channel. Preliminary calculation, including gravity effects, shows that the result is reasonable. This study provides a basis for the theoretical and experimental investigation of convective melting of solid particles in a fluid.
Effective Thermal Conductivity of the Mushy Region During Solidification of Aqueous Solutions of Ammonium Chloride
Authors: Bianchi Marcus V. A. , Viskanta Raymond 
Published: December 2021

Abstract
A theoretical and experimental study of the diffusion-controlled solidification process of an aqueous solution of ammonium chloride has been performed to obtain fundamental understanding relevant to metal casting, solidification of alloys, and freezing of biological materials. The effective thermal conductivity of the solidifying system is calculated using different models and the model predictions are compared. The model is validated by comparing the predictions with experimental data. It was found that, for the conditions considered in the present study, the parallel model, which is a simple average of the thermal conductivities of the two phases, leads to acceptable results. The reasons for this are related to the size of the mushy region and the morphology of the crystals during the solidification process.
Solidification Processing of Functionally Graded Materials by Sedimentation
Authors: Gao J. W. , White S. J. , Wang C. Y. 
Published: December 2021

Abstract
A combined experimental and numerical investigation of the solidification process during gravity casting of functionally graded materials (FGMs) is conducted. Focus is placed on the interplay between the freezing front propagation and particle sedimentation. Experiments were performed in a rectangular ingot using pure substances as the matrix and glass beads as the particle phase. The time evolutions of local particle volume fractions were measured by bifurcated fiber optical probes working in the reflection mode. The effects of various processing parameters were explored. It is found that there exists a particle-free zone in the top portion of the solidified ingot, followed by a graded particle distribution region towards the bottom. Higher superheat results in slower solidification and hence a thicker particle-free zone and a higher particle concentration near the bottom. The higher initial particle volume fraction leads to a thinner particle-free region. Lower cooling temperatures suppress particle settling. A one-dimensional solidification model was also developed, and the model equations were solved numerically using a fixed-grid, finite-volume method. The model was then validated against the experimental results, and the validated computer code was used as a tool for efficient computational prototyping of an Al/SiC FGM.
Study on Subcooled-Forced Flow Boiling Heat Transfer and Critical Heat Flux of Solid-Water Two-Phase Mixture
Authors: Koizumi Yasuo , Ohtake Hiroyasu , Mochizuki Manabu 
Published: December 2021

Abstract
The effect of solid particle introduction on subcooled-forced flow boiling heat transfer and a critical heat flux was examined experimentally. In the experiment, glass beads of 0.6 mm diameter were mixed in subcooled water. Experiments were conducted in a range of the subcooling of 40 K, a velocity of 0.17–6.7 m/s, a volumetric particle ratio of 0–17%. When particles were introduced, the growth of a superheated liquid layer near a heat trasnsfer surface seemed to be suppressed and the onset of nucleate boiling was delayed. The particles promoted the condensation of bubbles on the heat transfer surface, which shifted the initiation of a net vapor generation to a high heat flux region. Boiling heat trasnfer was augmented by the particle introduction. The suppression of the growth of the superheated liquid layer and the promotion of bubble condensation and dissipation by the particles seemed to contribute that heat transfer augmentation. The wall superheat at the critical heat flux was elevated by the particle introduction and the critical heat flux itself was also enhanced. However, the degree of the critical heat flux improvement was not drastic.