bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Shape Control of Active and Sensory Piezoelectric Composite Plates
Authors: Lee Ho-Jun , Saravanos Dimitris A. 
Published: March 2022

Abstract
Previously developed mechanics for piezoelectric composite materials are extended to account for thermal effects. The updated mechanics accounts for thermal effects which arise due to: (1) coefficient of thermal expansion mismatch between the various composite and piezoelectric layers, (2) pyroelectric effects on the piezoelectric plies, and (3) the temperature dependence of the composite and piezoelectric properties. The coupled mechanical, electrical, and thermal response of piezoelectric composite materials is captured at the material level. A layerwise laminate theory is formulated with the inherent capability to model both the active and sensory response of piezoelectric composite materials. Finite element equations are developed and implemented for a bilinear plate element. Numerical studies are conducted on a simply supported graphite/epoxy plate with attached piezoceramic patches to investigate thermal shape control applications and to study the resultant stress state.
Dynamics for Large Deflections of a Sandwich Plate With Thin Piezoelectric Face Layers
Authors: Yu Y. Y. 
Published: March 2022

Abstract
The frequency range for structural dynamics and vibration is first discussed. Nonlinear dynamics for large deflections of a sandwich plate is then reviewed. Finally, large deflections of a sandwich plate with two thin piezoelectric PVDF face layers are treated, and governing equations of motion are derived.
Analysis of Curved Sandwich Panels With Cutouts Subjected to Combined Temperature Gradient and Mechanical Loads
Authors: Noor Ahmed K. , Peters Jeanne M. 
Published: March 2022

Abstract
The results of a detailed study of the effect of the cutout on the response of curved sandwich panels are presented. The panels have honeycomb core composite face sheets. The loading consists of a temperature gradient through-the-thickness combined with pressure loading and edge shortening or edge shear. The analysis is based on a first-order shear-deformation Sanders-Budiansky type theory with the effects of large displacements, moderate rotations, transverse shear deformation and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, principal strains, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in the panel parameters, the effective properties of the face sheet layers and the core, and the micromechanical parameters. Numerical results are presented for cylindrical sandwich panels and show the effects of variations in the loading and the size of the cutout on the global and local response quantities and their sensitivity to changes in the various panel, effective layer and micromechanical parameters.
The Application of Sandwich Components in Hybrid Structures
Authors: Starlinger Alois 
Published: March 2022

Abstract
A hybrid design concept for body shells has been developed in order to achieve light and stiff structures for state of the art railway and bus vehicles. It uses longitudinal hollow aluminum extrusions combined with foam core sandwich panels of aluminum face layers. In addition to the reduction of mass, hybrid design helps to save production costs. These savings are based on the simplified assembling technique in a modular concept (via corner bolt systems, viscoelastic adhesives, riveting and laser welding), the integration of insulation (by the foam core), and the outstanding impact behavior. The direct joining of the sandwich composite elements to the aluminum extrusions is, however, one of the most challenging steps when designing a hybrid structure. For this reason the hybrid design concept requires a more sophisticated structural analysis approach. In the case of the composite components reduced shear stiffness of the core and local failure mechanisms have to be taken into account. In order to meet all the structural criteria detailed finite element models and analyses have been derived.
Several examples of railway structures built in the hybrid design are given to show the development steps and the advantages of this new design concept.
Strain Rate Compression Performance for a Linear Core Sandwich Beam, I
Authors: Weissman-Berman Deborah 
Published: March 2022

Abstract
One of the principal manifestations of history dependence in a linear type foam core is rate dependence. This paper details the response in compression to increased strain rate; the test response for a linear core material; the dynamic characteristics of foams; the equation of state for cored sandwich material, including the derivation of the elasto-plastic modulus and the derivation of the dilatational portion of plastic response. Compressive predictive equations are derived and correlated to test data. Finally it is concluded that the damping and modulus of resilience characteristics of the linear core material change within a narrow bandwidth of strain rate which may be a factor in determining the natural frequency of response for linear core sandwich constructions.
Forced Response Analysis of Gas Turbine Rotor Blades Using CFD-Based Aeroelastic Tools
Authors: Kruse Marlin J. , Liu Jong S. , Marenghi Yves G. , Eick Christopher D. 
Published: March 2022

Abstract
Integration of computational fluid dynamics (CFD) and structural dynamics codes is critical to the advancement of turbomachinery designs. This paper describes the successful integration of the CFD code UNSFLO with the structural dynamics code ANSYS® for a case study rotor. To evaluate the software combination, AlliedSignal Engines (AE) intiated a program to compare experimental observations from a set of high-pressure turbine tests to analytical predictions from UNSFLO and ANSYS®. The rotor under investigation exhibited significant blade vibratory response due to pressure wakes from upstream stator vanes. Experimental data, collected on two stator-rotor configurations, indicates dramatic strain reductions when the axial space between the stator and rotor blades is increased. Forced response analyses, which compare favorably to the experimental data, indicate a 90 percent reduction in vibratory strain levels.
Aerodynamic Response of Turbomachinery Blade Rows to Convecting Density Wakes
Authors: Ramer Becky E. , Wijesinghe Sanith , Tan Choon , Covert Eugene E. 
Published: March 2022

Abstract
Convecting density wakes have not been considered as a source of unsteady aerodynamic loading on turbomachinery blade rows. These unsteady loads could influence high cycle fatigue failure of blades and vanes in gas turbine engines. The goals of this study are to understand the temporal evolution of density wakes and to determine key controlling parametric trends on blade loading. Inviscid numerical calculations are conducted to illustrate the basic flowfield in the absence of boundary layer interactions. The profile and scaling of the unsteady loads is given here for two density gradient distributions.
The Role of Threshold Fatigue Crack Growth in Life Prediction of the Alloy Ti-6Al-2Sn-4Zr-6Mo Under High Cycle Fatigue Spectra
Authors: Larsen James M. , Russ Stephan M. , Maxwell David C. , Worth Brian D. 
Published: March 2022

Abstract
Damage tolerance methods are widely used to assure reliability of fracture critical components in advanced gas turbine engines. Although low cycle fatigue often determines component lifetime, high cycle fatigue of airfoils and airfoil attachment regions is a growing concern. Crack-growth-rate behavior tends to dominate life under low cycle fatigue, but crack formation and the threshold crack growth condition, ΔKth, are crucial under high cycle fatigue. In addition to material-dependent effects, key factors controlling fatigue crack growth thresholds in titanium alloys used in turbine engines include effects of load spectra, crack geometry, crack size, and residual stress. The utility of ΔKth as a life prediction criterion is examined under load histories that contain both low and high cycle fatigue. These results are discussed with respect to life management methods used for titanium-alloy fan and compressor components in high performance turbine engines.
Micromechanics Study of Plastic Zone at Crack Tip in Steel Under Cyclic Load
Authors: Wang Qing , Du Ming-Liang , Chiang Fu-Pen 
Published: March 2022

Abstract
A novel experimental micromechanics technique SIEM (Speckle Interferometry with Electron Microscopy) is employed to examine the plastic deformation field at crack tip during fatigue process. A fatigue cracked specimen made of AISI-SAE 1035 carbon steel was tested under a three-point bend load. Both displacement and strain fields were mapped over an area of 50μm by 40μm at the crack tip. Accumulation of the local damage due to fatigue was revealed by showing the evolution of the plastic zone at the crack tip. Crack growth was found in mixed mode at small scale. The variation of plastic crack opening displacement with the number of fatigue cycles in both mode I and mode II were determined. Two mechanism of crack propagation, crack branching and crack-wake ligament bridging, were observed and clearly demonstrated on the deformation map.
Micromechanics of High Cycle Fatigue in Single and Polycrystals
Authors: Lin T. H. , Wong K. , Teng N. J. 
Published: March 2022

Abstract
The micromechanic analysis of a fatigue band in the most favorably oriented crystal at the free surface of a polycrystal is reviewed. The localization of plastic strain in thin slip bands under monotonic loadings and the ratchet mechanism of fatigue bands provided by the stress fields of two closely located parallel thin slices sliding in opposite directions are shown. Each of these two thin slices slides monotonically. The alternate sliding of the two thin slices results in the macroscopic forward and backward plastic strain in cyclic loading.
Single crystals are used in turbine engine parts. The fatigue band analysis of polycrystals is extended to analyze the fatigue band in single crystals. Hysteresis loops of a single crystal under constant stress amplitudes and under constant plastic strain amplitudes are shown. Two sets of these hysteresis loops, one with small initial stress and one with large initial stress, are presented. These calculated hysteresis loops explains the two diagonal sharp corners in each loop to be due to reversals of loadings.
Two-Phase Gas-Liquid Slug Flow in the Transient and Steady States
Authors: Hewitt G. F. 
Published: March 2022

Abstract
A review is presented of recent results obtained at Imperial College, London on two-phase gas-liquid slug flow in horizontal pipes. The survey begins by reviewing work on the mechanism for transition between stratified flow and slug flow. Correlations for slug frequency are then discussed. Next, models for prediction of slug creation and evolution are reviewed; it is shown that slug formation is a complex process, occurring at various distances from the entrance. The application of one-dimensional two-fluid models to the prediction of slug formation and evolution is discussed and their limitations reviewed. Experimental and CFD studies of slug tail and slug front behaviour are then described and Ute inclusion of the results of this work into an overall slug evolution model is discussed. Finally, transients involving slug flow are reviewed and exemplified by a transient in which the gas flow is reduced (a “down-gas” transient). Predictions of such a transient using a commercial two-fluid model code are used to illustrate the difficulties that can be encountered in such predictions.
Snake and Corkscrew Waves in Core-Annular Flow
Authors: Renardy Yuriko Y. 
Published: March 2022

Abstract
Core-annular flow of two fluids in down-flow is examined at the onset of a n = ±1 non-axisymmetric instability. This leads to a pattern selection problem; the bifurcating solutions are traveling waves and standing waves. The former travel in the azimuthal direction as well as the axial direction and would be observed as corkscrew waves. The standing waves travel in the axial direction but not in the azimuthal direction and appear as snakes. Weakly nonlinear interactions are studied to see whether one of these waves will be stable to small amplitude perturbations. The corkscrews are found to be preferred when the armulus is narrow and snakes are preferred when the annulus is wide.
Flow Characteristics of Condensing Two-Phase Flow in Horizontal Microfin Tubes
Authors: Nozu Shigeru , Honda Hiroshi 
Published: March 2022

Abstract
Flow observation study along with local heat transfer and pressure drop measurements were conducted during condensation of CFC11 in horizontal microfin tubes. A smooth tube and two microfin tubes with different fin geometry were tested. Flow observation study with use of industrial borescopes revealed that two major flow patterns exist during complete condensation of a vapor. A correlation equation for the local frictional pressure gradient was derived, in which the effect of refrigerant mass velocity was introduced on the basis of the flow regime consideration. The condensing two-phase frictional pressure drop data for the microfin tubes were correlated by the present method to have a mean absolute deviation of 8.3 percent.
Fluids Engineering Division Conferences
Authors: Morrow Thomas B. 
Published: March 2022

Abstract
The ASME Fluids Engineering Division (FED) sponsors technical sessions at the FED Summer Meeting (FEDSM) and at the International Mechanical Engineering Conference and Exhibition (IMECE). This paper describes the FED’s role in the way in which these conferences are planned, organized, publicized and presented, and provides information on FEDSM attendance, registration fees and conference publications.
Collision Behavior of a Water Droplet With a Hot Surface
Authors: Fujimoto Hitoshi , Hatta Natsuo , Takuda Hirohiko 
Published: March 2022

Abstract
This paper treats the deformation process of a water droplet impinging on a hot surface above the Leidenfrost temperature. Emphasis is placed on the effects of the kind of surface material and the surface temperature on the deformation process. The surface material used are stainless-steel and silicon. The surface temperature is fixed at 673K and at 773K. It has been found that the time histories of droplet diameter as well as height on two kinds of surfaces are very similar in low Weber numbers such that the droplet rebounds from the surface without disintegration. However, the critical Weber number whether or not the droplet breaks up into some pieces on the surface during deformation has been confirmed to be changeable depending upon the kind of surface material. Furthermore, it has been confirmed that the effect of surface temperature on the droplet deformation process is remarkable in the later deformation period for the case of the low Weber number.
Collision Dynamics of Two Droplets
Authors: Fujimoto Hitoshi , Hatta Natsuo , Takuda Hirohiko 
Published: March 2022

Abstract
This paper treats the numerical analysis of the deformation behavior of liquid after head-on collision of two droplets. The simulation of the liquid deformation process has been performed using the MAC-type solution method to solve a finite differencing approximation of the Navier-Stokes equations governing an axisymmetric incompressible fluid flow. When a water droplet collides head-on into another one with small initial Weber numbers, two droplets coalesce and remain permanently united. For larger Weber numbers, two droplets merge temporarily and subsequently separate into two or more drops. The calculated free surface configurations have been in qualitative agreement with the experimental results observed by other researchers. Also, the critical Weber number to predict coalescence/separation of liquid after head-on collision has agreed with the experimental data. The details of droplet deformation mechanism have been discussed from a qualitative as well as quantitative point of view.
Detailed Characterization of Fuel Droplets in a Spray Flame Using an Integrated Phase Doppler/Rainbow Refractometer System
Authors: Sankar Subramanian V. , Robart Didier M. , Bachalo William D. 
Published: March 2022

Abstract
The characteristics of fuel droplets burning in an unconfined, non-swirling spray flame have been experimentally studied in great detail using an integrated phase Doppler/Rainbow Refractometer system. This newly developed non-intrusive diagnostic instrument allows for the measurement of individual fuel droplet temperatures in addition to their diameter and velocity. The fuel used for this study is hexadecane (C16H34) which has a boiling point of about 287°C. A solid cone Hago pressure atomizer with a flow rate of 0.5 gph was used to atomize the liquid fuel, and a spray flame was established by firing the atomizer vertically upward. Droplet temperature, size, and velocity data were obtained at several radial and axial locations within the spray flame. The study revealed that at the center of the spray, the droplets were well below their boiling point. Within the flame zone, the droplets had higher mean temperatures. A strong dependence of temperature on droplet size was also observed within the flame zone. The largest drops were close to room temperature whereas the temperature increased asymptotically to temperatures close to the boiling point with decreasing droplet diameters.
Measurement of Sphere Drag in High Turbulent Intensity Flows
Authors: Sankagiri Narayanaswamy , Ruff Gary A. 
Published: March 2022

Abstract
Multiphase flows composed of dispersed phase elements interacting with a turbulent continuous phase are encountered in many engineering applications. In analyses of these systems, the sphere drag coefficient is frequently used to determine not only the rate of momentum transfer from these elements but also the rates of mass and energy transport. Considerable research has demonstrated that the drag coefficient is dependent on the turbulence intensity of the free stream but experimental studies have been limited to relatively low levels of turbulence intensities, and have been obtained over limited ranges of particle Reynolds numbers. The objective of this research is to obtain data at low levels of turbulence where existing data is sparse or inconsistent, extend the measurements to higher levels of relative turbulence intensity, and cover the range of particle Reynolds numbers found in typical multiphase flows (50 &lt; Rep &lt; 1500, 0.08 &lt; Ir &lt; 0.6). Current drag measurements at turbulence intensities of approximately 0.1 show good agreement with the results of previous researchers. Results at an intensity of 0.3 have indicated how the drag coefficient transitions between high and low Reynolds number data from different researchers. Measurements at other turbulence intensities are continuing.
Numerical Modeling of Flow Over Dunes in Ice-Covered Channels
Authors: Tan Cheng-Ann 
Published: March 2022

Abstract
This paper presents a recently undertaken study of flow over dunes in an ice-covered channel. A fully three-dimensional numerical model was selected to simulate the flow physics. The model solves the complete Reynolds-averaged Navier-Stokes (RANS) equations, closed with the standard k-ε turbulence model. Small-scale bed roughness at the river bed and ice cover, is accounted for by using two-point wall-functions. A comparative study of ice-covered and open channel flow is presented to illustrate the differences in flow physics due to ice cover. Effects of varying roughness of ice on the flow physics is also investigated. Comparisons with measurements reveal the ability of the model to capture experimental trends with remarkable accuracy.
Quantitative Radiography for Transient Multidimensional, Multiphase Flows
Authors: Theofanous Theo G. , Angelini Sergio , Chen Xiaoming , Luo Rui , Yuen Walter W. 
Published: March 2022

Abstract
As computations of transient, multidimensional, multiphase flows are becoming increasingly more realistic, so increases the demand for their detailed experimental validation. Key in this task is the evolution of flow patterns, and the usual approaches of local measurements are inherently limited in meeting this demand. In this paper, we demonstrate the particular suitability of flash X-ray radiography, and the feasibility of reliably quantifying the radiographs of flow regions of various sizes, from microscopic to rather large scale.
Imaging of Particle Shear Migration With Electrical Impedance Tomography
Authors: Butler Jason E. , Bonnecaze Roger T. 
Published: March 2022

Abstract
Electrical impedance tomography is used to investigate the net migration of particles in a suspension undergoing pressure-driven flow through a tube at low Reynolds number. A low frequency electrical current is applied to the flowing suspension by two flush-mounted electrodes on the pipe wall to create a potential field which is sampled by other pairs of flush-mounted electrodes. A numerical inversion of the data, which takes into account the geometry and symmetry of the problem, gives the conductivity variation within the flow. An image of the suspension particle volume fraction in the tube is then formed using a relationship between the local conductivity and local suspension concentration. Consistent with particle shear migration of a concentrated suspension, the images from experimental data show a net migration of particles toward the centerline of the tube. The images favorably compare to an existing continuum theory of particle shear migration.
An Electrical Impedance Method for Measurements of Attached Cavitation
Authors: Ceccio Steven L. , George Darin L. 
Published: March 2022

Abstract
An electrical impedance probe is described which will be used to study the properties of attached cavitation. The method uses a series of electrodes mounted flush to the surface of a cavitating hydrofoil, and detects the presence of liquid or vapor through changes in the impedance of the local fluid medium. Characteristics of steady and unsteady attached cavitation, including cloud shedding and re-entrant jets, are reviewed. The impedance technique is shown to have the potential to measure advection velocities of bubble clouds, velocities of re-entrant jets, and frequencies associated with unsteady cavitation.
Instrumentation and Measurement Techniques for Multiphase Flow: The State-of-the-Art
Authors: Hussein Esam M. A. , Ingham Paul J. 
Published: March 2022

Abstract
This papers reviews recent progress in multiphase flow measurement methods and assesses the capabilities and limitations of developed or proposed techniques. Instrumentation for measuring global and local phase volume-fraction, phase-distribution, flow-pattern visualization and identification, interfacial area, phase-velocity and other parameters are examined. The paper concludes by identifying some of the most promising techniques and defining the remaining challenges.