bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation of Measured Shoe Forces and Surface Quality in Centerless Grinding
Authors: Monahan Richard W. , McFarland D. Michael 
Published: March 2022

Abstract
The objective of this research was to experimentally study the forces imparted on the workpiece during a typical shoe centerless grinding cycle on a flat (unprofiled) outer diameter. The data obtained provide insight into the forces developed between the machine structure and workpiece during both idling and steady-state grinding. These workpiece-machine structure interactions involve the grinding wheel, support shoes, and magnetic driver plate. The influence of the work-piece rotational center offset on the resultant shoe forces was examined by varying the workpiece rotational center relative to the fixed rotational center of the magnetic driver plate. The magnitude and direction of the resultant force and its effect on the final workpiece surface finish quality were examined.
Improving Gear Profile With an Electroplated CBN Wheel for High Accuracy Gear Profile Grinding & the Development of a Truing Machine for High Accuracy Wheel Grinding
Authors: Masaki Ryuzo , Nagata Hiroshi , Hisada Jiro 
Published: March 2022

Abstract
Load capacity of gears could be remarkably improved by making their tooth surface roughness smaller than 1μm Ry. In order to produce such gears, the authors developed a precision CNC gear grinding machine of the forming type. The shortcomings in using the above grinding machine was that the productivity of grinding with a conventional wheel was low, and the layer below the ground surface was occasionally damaged by a residual tensile stress.
Consequently, to supplement the precision grinding process, the authors also developed a microtruing machine which creates a high accuracy profile and a uniform grain height of the electroplated cBN grinding wheel.
The machine realized an axial stiffness of 300N / μm on the wheel spindle, and a positioning accuracy of about 50 ran. A conventional wheel was microtrued on the microtruing machine and tested for grinding a gear. The gear profile error, was 1 μm.
Chatter Suppression via an Oscillating Cutter
Authors: Yang Fulun , Zhang Bi , Yu Junyi 
Published: March 2022

Abstract
Chatter is one of the critical issues in a machining process since it deteriorates the surface quality of a workpiece and reduces machining efficiency. A new method is developed to suppress chatter in which an oscillating cutter is used to machine the workpiece through a stepping motor and a transmission mechanism so as to vary tool rake angle continuously and periodically in process. Theoretical analyses are performed on the stability of the cutting system, and verified by the experimental studies. Both theoretical analyses and experimental results indicate that the method can suppress chatter effectively. With the application of an oscillating cutter, the amplitude can be reduced by 80% in cutting a steel workpiece.
Analytical Expression of the Damping Characteristics of Air-Lubricated Slideways for Machine Tools
Authors: Kato Shigeo 
Published: March 2022

Abstract
Analytical expression of the damping ratio and the natural frequency of air-lubricated slideways are presented. By the research, the damping characteristics of air-lubricated slideways is represented by a transfer function which has a first-order formula in the numerator and a third-order formula in the denominator. The third-order denominator of the transfer function which shows damping characteristics of air-lubricated slideways is analytically resolved to factors, a first-order delay system with the fast decay (time constant T3) and a second-order vibration system with damping. Air-lubricated slideway has two time constants T1 and T2 which represent the damping characteristics of the slideway. The damping ratio of the slideway ζ0 is analytically expressed by the time constant T2, the natural frequency of the slideway ωn, and dimensionless number k that is the ratio of T2 and T3 as ζ0 = k(1 − k)/(2T2ωn).
Crash Worthiness of Automobile Mechanisms
Authors: Salmon J. L. , Nayfeh A. H. 
Published: March 2022

Abstract
Two methods for performing transient inertia analysis of vehicle mechanism systems are presented in this paper. The analysis techniques are used to predict the response of automotive mechanisms to the accelerations associated with vehicle impacts. General analytical methods for evaluating rotational system dynamics are presented. The utility of the techniques are demonstrated by evaluation of a vehicle outside door handle. The methods, along with time dependent accelerations associated with vehicle impact, are used in a specific example to perform a dynamic analysis of an automobile outside door handle. The first method utilizes generalized Lagrange equations for a non-conservative system to formulate a second order nonlinear differential equation that defines the response of the handle components to the transient input. The differential equation is solved numerically by employing a fourth order Runge-Kutta method. The second method uses commercially available two dimensional rigid body dynamics software to evaluate the events. The results predicted using the analytical techniques are compared to experimental data generated by high speed film analysis of latch tests performed on a high G acceleration sled at Ford Motor Company.
Some Studies for the Application of Explicit FE Codes in Simulation of Quasi-Static Tests
Authors: Lu David X. , Shahidi Behrooz K. , Rivard Cliff M. , Li Rihua 
Published: March 2022

Abstract
Explicit algorithms have been applied to study quasi-static large deformation contact problems with the use of some non-physical acceleration methods for the improvement of computation efficiency. Numerical errors caused by those non-physical acceleration methods are studied in this paper. It is found that oscillation will be introduced if one uses dynamic approach to study a quasi-static problem. Numerical errors caused by dynamic approach will be increased when non-physical acceleration techniques, such as Speed-Up-Loading and Mass-Scaling, are applied.
Front End Design of Vehicle Structure Subjected to Frontal Crash Load
Authors: Mahmood Hikmat F. , Li Chunhui 
Published: March 2022

Abstract
This paper describes a straightforward and effective development process to formulate a frontal end structure to meet the crash safety requirements. The process developed provides a progressive localized buckling behavior for maximum energy absorption. The design and analysis are implemented by using a finite element collapsible beam theory to predict the strength and mode of collapse of the front end components and subsystem. A simplified lumped mass-spring system is proposed for predicting crash performance using the various components characteristic. The springs used in the model representing major energy absorption components and their stiffness are analytically obtained from FEA beam code. The effects of the crash on occupant response are simulated by a MADYMO model. The final designs are experimentally verified using dynamic test of full scale structure. Correlation between analysis and test is good and the structure achieves the desired crush characteristics in crush length, peak, and mean loads. This process provides a rapid develop tool toward an efficient structure for frontal crash energy absorption early in the vehicle program.
Computational Modeling of Axial Neck Impact: Influence of Head Motion and Cervical Spine Buckling on Dynamic Behavior
Authors: Camacho Daniel L. A. , Nightingale Roger W. , Myers Barry S. 
Published: March 2022

Abstract
A computational head-neck model was developed to better understand the influence of head motion and cervical spine buckling on dynamic responses to near-vertex head impact. The model consisted of rigid vertebrae interconnected by assemblies of nonlinear springs and dashpots, and a finite element shell model of the skull. Model parameters were based upon quasi-static pure moment testing of cadaveric cervical spine motion segments and existing data reported in the literature. Geometric and inertial characteristics were derived from three-dimensional reconstructions of skull and vertebral CT images. The model correctly reproduced the complex cervical spine buckling deformations observed in high speed video of near-vertex impacts to cadaveric head-neck specimens, including a buckle at 6 msec and subsequent local post-buckled regions of both flexion and extension. Head and neck load histories agreed with those reported in the cadaveric studies. Sensitivity analyses of the cervical spine modeling parameters revealed that head and neck responses were most sensitive to changes in flexion-extension properties, consistent with structural stability theory for a slender column buckling under compressive loads. A sensitivity analysis of head mass demonstrated that even in the absence of a pocketing impact surface, the head inertia can oppose translational motion of the upper cervical spine during impact, resulting in increased neck loads.
Modeling and Analysis of Passive Moving Seat for Improved Safety
Authors: Tarabishy M. Nabeel , Dollar Anna , Cammino Roberto A. 
Published: March 2022

Abstract
Although current safety systems in passenger cars which include seat belts, frontal airbags, and more recently side airbags, are effective means in reducing injury in the case of accidents, there is still much room for improvement on existing systems, or addition of new ones. This paper introduces a novel system that can be added to existing designs to further reduce the injuries sustained in automobile accidents. The design calls for absorbing some of the crash energy by allowing the seat to move with respect to the chassis through a limited distance. As a result, the impact profile is affected, and therefore, the severity of the crash is reduced. Simulation runs on a simple passenger model at 35 mph have shown a reduction of HIC (Head Injury Criteria) from 1300 to 450 when this design is implemented.
Natural Convection Heat Sink With Heated Shroud
Authors: Morrison Andrew T. , You S. M. 
Published: March 2022

Abstract
Numerical solutions for laminar natural convection in a vertical shrouded fin array are presented. Analysis of a physically realizable configuration is compared to published results for an adiabatic shroud. The effect of a uniform heat flux on the heat sink shroud representing an incident solar heat load is also examined for a vertical heat sink with natural convection and radiation. Comparison to closed form relations for laminar flow between plates lends some insight into the influence of the developing boundary layer on the heat sink thermal performance. Some heat transfer enhancement beyond that of an adiabatic shroud was observed at high Grashof numbers. At low Grashof numbers the Nusselt number was lower than for an adiabatic shroud. However, compared to no shroud, the presence of a shroud at any distance from the fin tip improved the transfer of heat from the fin array. The benefit of the shroud when a heat load is present appears to be greatest for a shroud clearance of C = 0.5 to 1.0.
Contact Area and Thermal Contact Resistance in an Ideal Bolted Joint: Part 2 — Study of Thermal Contact Resistance
Authors: Park Chang J. , Kaminski Deborah A. 
Published: March 2022

Abstract
The thermal contact resistance at the interface of a bolted joint was investigated analytically, experimentally and numerically. Consideration was restricted to an ideal two-plate model for which the interface was perfectly flat. The two bolted plates made circular contact under uniform axisymmetric normal loading. The effect of important system parameters such as plate thickness, material property and loading radius were investigated.
In the analytical study, a closed form solution for the thermal contact resistance for a bolted joint was derived. A three-dimensional heat conduction equation was applied to a model which had a circular geometry and isoflux boundary conditions. The model was solved by the method of separation of variables and superposition. The results showed that an isoflux condition at the interface was valid when thermal conductivities and thicknesses of the top and bottom plates were equal or close to each other.
In the experimental study, the temperature drops were measured across a bolted piece with an interface and these were compared with drops across one solid piece without the interface at low air pressure. Only copper was used and all the copper plates had mirror-like surface finishes. The values of thermal contact resistance obtained from the experiment were consistently lower than those from the numerical analysis, due to air pressure in the vacuum chamber.
In the numerical study, isothermal and isoflux boundary conditions were used. The results of this investigation would be useful in the design of cooling for high power electronic devices bolted on heat sinks.
Analytical Feasibility of Laser Induced Stress Wave Thermometry Applied to Silicon Wafers
Authors: Rabroker G. Andrew , Suh C. Steve , Burger Christian P. , Chona Ravinder 
Published: March 2022

Abstract
A model correlating the group velocity of guided plate waves to temperature in anisotropic silicon substrate is presented. The model is developed through numerical solution and manipulation of the dispersion relations while elastic constants are treated as functions of temperature. Results demonstrate that adequate thermal resolution is provided by both the lowest order antisymmetric and symmetric dispersive Lamb wave modes to serve as an effective diagnostic in a non contact thermometry scheme in rapid thermal processing (RTP) of silicon wafers.
Measurement of Solder-Copper Interfacial Fracture Parameters Using u2-Displacement Fields
Authors: Tippur H. V. , Krishnamoorthy H. 
Published: March 2022

Abstract
Moiré interferometry is used for mapping elasto-plastic deformations in 63/37 solder-copper bimaterials subjected to predominantly tensile loading. A method for quantifying the fracture parameter — the J-integral — using full-field measurement of u2-displacements has been developed. A linear relationship between crack tip opening displacements (CTOD) and the J-integral is demonstrated. The crack growth resistance curve and hence crack initiation toughness JC for the bimaterial is obtained. Full-field optical information has also suggested the possibility of using a simpler method for the J-integral estimation using a single strain gage.
Testing and Measurement Techniques Applied to Electronic Packaging Development
Authors: Guo Yifan , Sarihan Vijay 
Published: March 2022

Abstract
Electronic packages are complicated material systems operating under thermal and mechanical loading conditions. The package design and reliability analysis requires knowledge in many technical disciplines and specialized experimental methods and tools. Recently, many advanced techniques are adopted from other technical areas to be applied to the packaging applications and many experimental tools are developed correspondingly. In this paper advanced experimental techniques in electronic packaging are reviewed. The techniques and methods for mechanical analysis are emphasized as well as the new development in equipment and tools. The applications of these techniques are introduced by numerous reference publications. Most of the applications are directly related to new product development and have made significant impact in the electronics industries by assisting product designs, qualifications, reliability predictions and cycle time reductions.
Moiré Interferometric Analysis of Crack Nucleation From Bimaterial Corners
Authors: Mohammed I. , Liechti K. M. 
Published: March 2022

Abstract
Bimaterial corners arise in many modem structural components from structural adhesively bonded joints to line structures in microelectronics devices. The elasticity problem has been extensively analyzed (Williams, 1952, Bogy, 1971, Hein and Erdogan, 1971) and it has been shown that singularities in stress can arise, depending on the properties of the materials and the corner geometry. These singularities (or eigenvalues) may be complex in nature and a number of them may co-exist for a particular configuration. Various schemes have been developed for extracting the stress intensity factors (or eigenvectors) associated with each singular term (Stem et al, 1976, Carpenter and Byers, 1987).
Advances in Tensile Testing of Polysilicon Thin Films
Authors: Sharpe William N. , Yuan Bin , Edwards Richard L. 
Published: March 2022

Abstract
Polysilicon is the most widely used material in current commercial MEMS products, yet its mechanical properties are not fully determined. Vapor deposited polysilicon is thin — on the order of a few microns — which makes handling and testing difficult. It is desirable to use mechanical tests similar to those standardized by ASTM, but this requires special techniques and procedures.
Tensile tests of 3.5 micron thick polysilicon film have been conducted and these are briefly described. Two advances in mechanical property testing are then presented. A preliminary investigation of the effect of hydrofluoric acid on the tensile properties of polysilicon shows no deleterious effect of this acid which is commonly used as a release agent. Fracture toughness testing of polysilicon, in which crack opening displacement is measured (an approach similar to that specified by ASTM), yields a preliminary value of 1.6 MPa-m1/2.
Hydrodynamic Coupling Between a Viscoelastic Gas/Liquid Interface and a Swirling Vortex Flow
Authors: Lopez J. M. , Chen Jinghong 
Published: March 2022

Abstract
While the structure and dynamics of boundary layers on rigid no-slip walls in rotation dominated enclosed flows are still an area of active research, the interactions between rotating or swirling flows with a free surface have received comparatively less attention. For the most part, investigations in this area have been focused on clean free surfaces, which may be treated as stress-free. However, in most practical situations the surface is rarely clean, and even under laboratory conditions, it is quite difficult to achieve a clean free surface. Most impurities in fluids are surface active, and hence the name surface active agent or surfactant. These surfactants tend to establish an equilibrium surface concentration which alters the interfacial tension and interfacial viscoelastic properties of the gas/liquid interface. The coupling between the bulk swirling flow and the interface is provided via the stress boundary conditions, and these are dependent upon the surface concentration of surfactant, which in turn is altered by the interfacial flow. Forces acting on the interface include surface tension gradients (elastic) and the viscous resistance to shear and dilation. These viscoelastic properties are functions of the surfactant concentration on the surface. Here, we present numerical studies of flow in a cylinder driven by the constant rotation of the bottom endwall with the top free surface being contaminated by a Newtonian surfactant. Comparisons with a clean free surface and a no-slip top endwall provide added insight into the altered dynamics that result from the presence of a small amount of surfactant.
Nonlinear Spin-Up of a Rotating Stratified Fluid: Theory
Authors: Hewitt Richard E. , Duck Peter W. , Foster Michael R. , Davis Peter A. 
Published: March 2022

Abstract
We consider the boundary layer that forms on the wall of a rotating container of stratified fluid when altered from an initial state of rigid body rotation. The container is taken to have a simple axisymmetric form with sloping walls. The introduction of a non-normal component of buoyancy into the velocity boundary-layer is shown to have a considerable effect for certain geometries.
We introduce a similarity-type solution and solve the resulting unsteady boundary-layer equations numerically for three distinct classes of container geometry. Computational and asymptotic results are presented for a number of parameter values. By mapping the parameter space we show that the system may evolve to either a steady state, a double-structured growing boundary-layer, or a finite-time breakdown depending on the container type, rotation change and stratification. In addition to extending the results of Duck, Foster & Hewitt (1997) to a more general container shape, we present evidence of a new finite-time breakdown associated with higher Schmidt/Prandtl numbers.
Modelling and Simulation of Rotating Buoyant Suspensions: Fundamentals and Challenges
Authors: Ungarish M. 
Published: March 2022

Abstract
The methodology used in the analysis of the flow-field of non-colloidal suspensions in a rotating system, accompanied by separation under the action of a centrifugal or gravitational field, is discussed. Some results for centrifugal separation and rotating particle-driven gravity currents are reviewed, and some new challenging questions that appear in the context of these problems are pointed out.
Particle Entrainment in a Bounded Rotating Flow With a Drain
Authors: Mang J. , Minkov E. , Schaflinger U. , Ungarish M. 
Published: March 2022

Abstract
A bathtub vortex is usually formed at the axis of a drain. In the presence of such a vortex, gravity separation of solid impurities lighter than the embedding fluid is counteracted by centrifugal separation and viscous resuspension. Both mechanisms are responsible for the agglomeration of impurities at the axis of the vortex. From there the impurities are easily sucked into the outlet.
In the investigated case, a viscous fluid with a given initial rotation is spinning down in a container with endplates both at the bottom and the top. The amount of fluid withdrawn through a circular hole in the center of the vortex is constantly replaced by a radial influx.
The resulting time-dependent flow was solved by means of a finite difference method taking into account the influence of Ekman layers at the bottom and the top. Subsequently, the process of centrifugal separation of particles lighter than the embedding fluid was studied according to the aforementioned flow field. The results were compared with the particle motion in a classical Oseen vortex. For a simplified case an analytical solution was derived and compared with the corresponding numerical solution. Both results were found to be in good agreement.
Particle Motion in Taylor Couette Flow
Authors: Wereley Steven T. , Lueptow Richard M. 
Published: March 2022

Abstract
Supercritical circular Couette flow devices with a suspension in the annulus between an inner rotating cylinder and an outer fixed cylinder are used for continuous mixing of suspensions and for rotating filtration. The motion of particles in suspension depends on both centrifugal sedimentation and transport due to the vortical motion of Taylor vortices, a centrifugal flow instability that results in a stack of toroidal vortices in the annulus. We have modeled the motion of particles in Taylor Couette flow using computational particle tracking in an analytic velocity field. The fluid velocity field was based on an analytic model that has been shown to accurately represent the flow field just above the transition to supercritical Taylor vortex flow. Particles of various densities were computationally placed in the analytic flow field and tracked to determine the preferential steady state particle positions. Since the centrifugal field goes to zero near the outer cylinder, particles near the outer cylinder are easily carried by the Taylor vortices toward the inner cylinder where they are exposed to the centrifugal field. Due to their density, particles near the inner cylinder centrifugally sediment outward. As a result, particles that start near the inner cylinder or the outer cylinder both tend toward a limit cycle orbit resulting in a region of clear fluid near the inner and outer cylinders and at the centers of the vortices.