bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Explicit Finite Element Study of Shear Localization During Orthogonal Cutting Process
Authors: Scott De-Shin Liu , Hong Jack 
Published: March 2022

Abstract
The shear localization phenomena during serrated chip formation in high speed orthogonal metal cutting process have been studied by using the explicit finite element analysis. A three dimensional computational model has been developed for analyzing dynamic thermomechanical deformations of a thermally softening viscoplastic workpiece material subjected to various tool cutting speeds and tool rake angles. The shear band characteristics such as temperature contour, effective plastic strain, effective plastic strain rate, propagating speed and orientation are investigated for each cases. Cutting forces can be estimated by this 3D model. The predictions of the finite element analysis are shown that above a critical high cutting speeds the secondary shear of the chip on rake surface appear to be a negligible effect which indicated the chip segments can be separate completely due to extensive shear in the primary shear zone; this phenomena agreed well with the experimental observations. The numerical model presented here can easily applied to study the oblique cutting process.
The Effect of Thermomechanical Strain Cycling on the Fatigue Life of Gas Turbine Material In-738LC: A Life Prediction Model
Authors: Zamrik Sam Y. , Renauld Mark L. 
Published: March 2022

Abstract
Experimental and analytical method is developed to address the effect of thermomechanical fatigue (TMF) on a nickel base superalloy which is a γ’/ (Ni3Al) strengthened material used primarily for land based gas turbine blading. A life prediction model is developed on the basis of a tensile hysteresis energy approach which incorporates the effect of creep, environment, and temperature. The developed life prediction model has shown a good predictive capability to correlate most of IN-738 out-of-phase TMF data from numerous researchers into a 3x scatterband. The TMF tests were carried out on two sets of cyclic temperatures of 482–816°C (900–1500°F) and 482–871°C (900–1600°F). In addition, isothermal tests were carried out at 816°C (1500°F) under strain ranges from 0.3% to 0.8% for life comparison between isothermal and TMF. The results show that the TMF out-of-phase type cycle is the most damaging cycle for the IN-738LC material when compared to both in-phase and isothermal cycles. All experiments were strain-controlled with a triangular waveform and an A-ratio (A = εamp/εmean) = ∞.
Scientific Implications in High Peak Power Nd:YAG Laser Material Removal of Al-30%SiC Composite
Authors: Nagarathnam K. , Chen X. , Mazumder J. 
Published: March 2022

Abstract
This paper outlines the scientific implications of a high peak power, high beam quality Nd:YAG laser in manufacturing applications and discusses the significance of optimizing key laser process parameters in material removal characteristics of a Al-30% SiC composite. The potential applications of this emerging technology are primarily targeted towards advanced components fabrication in industries such as aeronautic, space, power generation, and automotive. Some of the unique advantages include better beam characteristics such as focusability, improved dimensional accuracy and tolerance, higher production rates, process maneuverability using suitable lens and fiber optic beam delivery systems, and elimination of mechanical tool wear in comparison to the traditional drilling techniques. Percussion drilling experiments were performed in two batches on 12.5 mm thick plates of Al-30% by volume of SiC composite material. The laser consists of a cw-pumped Nd:YAG oscillator followed by a cw face-pumped, total internal reflection Nd:YAG slab for the amplifier gain medium, a master-oscillator-power-amplifier (MOPA) configuration. Both the second harmonic wavelength (532 nm) and the fundamental wavelength (1064 nm) were used, with average powers ranging from 35 W to 90 W. Two pulse formats were employed: Q-switched or simultaneously modelocked and Q-switched. A concentric nozzle was used with O2 assist gas at 45 psig pressure at the regulator. The holes were produced both normal to and 45° angle to the surface. Based on the measured geometrical data, circularity and dross ratios have been proposed and correlated with the process variables. The absence of cracking was evident from the transverse cross-sections of the produced holes. Results of the microstructural aspects such as the morphology and concentration of alloying elements in the matrix and second phase constituents of the unaffected substrate and the nearby regions of the laser drilled holes provided encouraging evidence for the retention of similar morphology, minimal heat affected zone, and little or no recast layer, under select process conditions. The findings in this present study emphasize the uniqueness of this modern laser material removal technique as an advanced manufacturing tool with broader future potential.
A Robust Design Methodology for Structural Control Using Piezoelectric Materials
Authors: Sunar M. , Hyder S. J. , Kahraman R. 
Published: March 2022

Abstract
Piezoelectric materials are modelled using finite element method. Steady thermal effects are included in the model. The model is used in piezoelectric control of flexible structures. The robustness of a piezoelectric control system consisting of a master structure and a pair of piezoelectric actuators is considered by the use of Taguchi methodology. The effects of the location, thickness and width of the actuators are investigated on the control performance of the system subjected to mechanical and steady thermal disturbances. Based on the numerical results it is concluded that the width of the actuators has the most profound effect on the control performance.
Passive Control of Multi-Jointed Structures
Authors: Ettouney Mohammed M. , Daddazio Raymond P. , Abboud Najib N. 
Published: March 2022

Abstract
Reducing the amplitude of structural response generated by noise sources such as machine vibrations using passive control measures is of interest to design engineers. This study will focus on the role of joints in multi-jointed structures in the passive control of structural response.
In a multi-jointed structure, joints play a major role in the response of the structure. First, joints regulate the equilibrium of the whole structure. In such a role, they can act, for example, to transform a pure axial wave in a horizontal member in the structure into a pure flexural wave in a vertical member connected to it at a joint. Second, they are the “recipients” of the noise sources from the secondary beams and floors of the structure. In such a role, joints act as a filter between the noise source and the rest of the structure. These two roles point to the possibility of modifying joints so as to passively control the response of a multi-jointed structure.
In this study, the addition of energy loss mechanisms, which are concentrated at the joints is evaluated. These energy loss mechanisms include adding filler materials with high loss factor. The different parameters affecting the structural response will be evaluated. These parameters include the amount of added material to the joints, relative loss factors of both structure and the added material and the degree of reductions in structural responses. In all the cases studied, a consideration of the practical engineering detailing of such systems will be discussed.
Nonlinear Oscillations of Circular Plates Near Critical Speed
Authors: Raman Arvind , Mote C. D. 
Published: March 2022

Abstract
The nonlinear response of an axisymmetric, thin elastic circular plate subject to a constant, space-fixed transverse force and rotating near a critical speed of an asymmetric mode, is analyzed. A small-stretch, moderate-rotation plate theory of Nowinski (1964), leading to von Kármán type field equations is used. This leads to nonlinear modal interactions of a pair of 1 – 1 internally resonant, asymmetric modes which are studied through first-order averaging. The resulting amplitude equations represent a system whose O(2) symmetry is broken by a resonant rotating force.
The nonlinear coupling of the modes induces steady state solutions that have no apparent evolution from any previous linear analyses of this problem. For undamped disks, the analysis of the averaged Hamiltonian predicts codimension-two bifurcations that give rise to sets of doubly-degenerate, one-dimensional manifolds of steady mixed wave motions. These manifolds of steady motions are bounded in phase space by either mode localized backward travelling wave branches or forward travelling wave branches. On the addition of the smallest damping, the branches of the backward travelling waves with equal modal content become isolated, and numerical investigations indicate the absence of any other types of steady motions.
Load Interaction Effects in Coupon Fatigue Tests Using a Railroad Tank Car Spectrum
Authors: McKeighan Peter C. , Smith Keith B. , Cardinal Joseph W. 
Published: March 2022

Abstract
The loaded vertical coupler force (LVCF) spectrum derived from an instrumented tank car and recorded from over-the-road service conditions is dominated by relatively small loads and also contains high peak loads. The focus of this work was to determine the extent to which the smaller loads in the spectrum can be truncated without adversely impacting crack growth behavior. The influence of clipping, or not achieving the peak tensile and compressive loads, was also investigated as well as the effect of the value used to scale the load spectrum into a stress sequence.
The truncation studies performed at two spectrum scale factors suggest that the two lowest stress levels in the spectrum (approximately 4–5 ksi full range stress level) can be omitted with little measurable effect on spectrum crack growth behavior. Furthermore, tensile and compressive peak load clipping of approximately 25 percent was observed to have little influence on spectrum crack growth behavior. Finally, under certain conditions, the coupon test data compared favorably to calculations utilizing a linear damage, unretarded and interaction-free analytical crack growth prediction model.
Rail Vehicle Dynamic Parameter Identification
Authors: Wilson N. G. , Urban C. L. , Burnett M. S. 
Published: March 2022

Abstract
A cost-effective method of experimentally determining rail vehicle dynamic parameters for use in analytical dynamic models has been developed by the Association of American Railroads (AAR). In this method, the rail vehicle’s rigid body modes of vibration are manually excited and the corresponding resonant frequencies are measured. Using these frequencies, the equations of motion for the system are solved for the vehicle’s mass moments of inertias, center of gravity location, and suspension stiffness. This method of dynamic parameter identification was developed at AAR’s Transportation Technology Center, Pueblo, Colorado.
Compared to competing experimental methods, the AAR method offers the advantage of cost-effectiveness; it requires no expensive equipment and can be executed at remote locations.
This paper describes the AAR method for rail vehicle parameter identification. An example of its use in the characterization of an iron ore rail vehicle is presented. In addition, dynamic simulation results for a transit vehicle, characterized using the AAR method, are compared to track test data for validation.
Condensation Enhancement on a Pool Surface Caused by a Submerged Liquid Jet
Authors: Shumway Rex W. 
Published: March 2022

Abstract
One advanced nuclear reactor design has a residual heat removal (RHR) pipe connected to the bottom of a steam generator outlet plenum. The water in the plenum can become thermally stratified during postulated loss of coolant accidents. Cold water injected through the RHR pipe has the potential effect of increasing the steam condensation on the pool surface due to the stirring action of the jet. The amount of increase depends on a number of factors, including the jet velocity and the pool height above the jet injection point. Prediction of steam condensation rates, before and after the jet breaks the pool surface, is the topic of this paper. Data and correlations exist for pre surface breakthrough and a method has been developed for post breakthrough. The models have been incorporated into the reactor safety analysis computer software known as RELAP5 (1995). Comparisons of predictions against data are presented.
Features of the Calculational Method at Fluid Flow Modelling
Authors: Černe Gregor , Petelin Stojan 
Published: March 2022

Abstract
The ADI (Alternating Direction Implicit) method is used for solving second order partial differential equations. In this case it is applied for viscid incompressible fluid flow described by the Navier-Stokes equation. The method is tested on the simple case of the abrupt area change for the several Reynolds numbers up to Re = 800. A vortex is formed already at low Reynolds number. It affects the pressure field and contribute to the phenomena complicity. The influence of the boundary conditions and nodalization density is also examined.
Bubbly Flow Identification Using Particle Image Velocimetry
Authors: Hassan Y. A. , Schmidl William , Ortiz-Villafuerte J. 
Published: March 2022

Abstract
The shape of a rising air bubble in a pipe flow is investigated with the Particle Image Velocimetry (PIV) flow visualization technique. To do so, a test volume of bubbly flow is globally illuminated with a pulsed light from a continuous wave laser with an acoustic-optic beam chopper, and is observed with four CCD cameras connected to frame grabbers. A digital image of the rising bubble is acquired and analyzed to identify its shape.
A reconstruction method, based on the Dynamic Generalized Hough Transform (DGHT), is described that can determine the two-dimensional shape of a bubble from a PIV image.
Optimization of the Compression (Injection/Compression) Molding Process Using Numerical Simulation
Authors: Davis Bruce A. , Theriault Richard P. , Osswald Tim A. 
Published: March 2022

Abstract
The increasing requirements on auto makers to reduce both the cost and weight of passenger vehicles as well as meet ever more restrictive government regulations make the use of fiber reinforced plastics very attractive. In particular, the use of thermoset composites, such as SMC and BMC, have been used for years by the major auto makers to produce high quality, strong, stiff, and lightweight body panels. Increasingly, it is being used for more structural components throughout the vehicle. However, the use of fiber filled thermoset composites is not limited to the automotive industry. It is also extensively used in electronic components, sports equipment, and general consumer goods. Accordingly, the need to be able to design these molded parts and to predict the complex behavior during manufacture and in service is paramount to reducing the time from concept to production.
This paper introduces a finite element based simulation program that allows the entire molding process, including mold filling, fiber orientation, heat transfer, cure, residual stress and warpage, to be simulated on the computer rather than by experimental prototyping. The software allows designers and engineers to determine product performance during the design stage before the tooling needs to be manufactured. Then, by modifying the design and process with the computer, part optimization can be accomplished prior to building the mold.
The paper discusses the models and methods implemented by the simulation program along with the accompanying assumptions. The results of the simulation are compared with experimental results for a variety of parts. This paper then highlights a case study of an injection/compression molded component showing how the simulation can be used as a design optimization tool.
Intelligent Processing of Carbon-Black Loaded Plastics
Authors: Bouda V. 
Published: March 2022

Abstract
The electrical conductivity of alternating current (AC) and permittivity of carbon-black (CB)-filled low density polyethylene (LDPE) has been measured as function of time at a temperature higher than the melting temperature of matrix polymer. The conductivities measured at lower frequencies (If) can be used for the characterization of the properties of the interlayer between the CB-particles. The conductivities measured at higher frequencies (hf) reflects the properties of the internal structure of the individual CB-aggregate. At a characteristic time t°, the lf AC conductivity suddenly increased up to the hf conductivity and the permittivity suddenly decreased. The CB aggregates are probably linked together by paracrystalline layers after a certain time of annealing. The time t° increases with the weight percent of CB. It was also found that t° increases as the temperature of annealing decreases. The time t° is interpreted as a relaxation of potential energy of electrostatic repulsion forces between the reversible disintegrated CB particles. The poor reproducibility and stability of CB-filled plastics can be explained by the observed changes of conductivity.
Microstructural Optimization of a Functionally Gradient Layer
Authors: Nadeau Joseph C. , Ferrari Mauro 
Published: March 2022

Abstract
This paper addresses the microstructural optimization of an infinite, transversely isotropic layer which is free of tractions and subjected to a prescribed thermal gradient. The layer’s microstructure is characterized as a bi-phase composite in the form of a continuous matrix perfectly bonded to embedded spheroidal reinforcements. The microstructural characterization of the FGM is taken to be the volume fraction, aspect ratio and orientation distribution function of the second phase. The composite layer is made functionally gradient by taking the aforementioned parameters to vary through the thickness of the layer. The effective properties of the bi-phase composite are obtained by appropriate homogenization theories. The microstructural parameters are determined such that an objective function, defined in terms of strain energy and curvature, is minimized. Specific results are presented for an aluminum (Al) layer reinforced with silicon carbide (SiC). Comparisons are made to conventional coating technology.
A Unified Micromodel for Constitutive Behavior of Metal Matrix Composites Undergoing Plastic Deformation
Authors: Kwon Y. W. , Kim C. , Yang G. Y. 
Published: March 2022

Abstract
The objective of this study is to develop a unified, three-dimensional micromodel which can describe the nonlinear elastoplastic constitutive behavior of MMC’s with continuous fibers, particles, or aligned short fibers as the reinforcement. In the micromodel, both the reinforcement and the matrix may have elastic and/or elastoplastic deformation(s), respectively. However, as in most cases, the development is shown for elastic reinforcement in an elastoplastic matrix. The micromodel uses a repeating unit-cell model with eight subcells. For a particulate or an aligned short fiber composite, one center subcell represents the particle or the short fiber while the rest of the subcells represent the matrix. On the other hand, two aligned subcells indicate the fiber for a fibrous composite. The micromodel yields the overall effective constitutive equation for an MMC with elastoplastic deformation in the matrix material. The effective stress-strain plots of various MMC’s are predicted using the micromodel for a wide variation of the reinforcement volume fraction. These results are compared to those obtained from the finite element analysis, and the two results agree very well.
Effect of Fiber Volume Fraction on Fully-Reversed Isothermal Fatigue Behavior of Unidirectional SCS6/Ti-15-3 Composites
Authors: Subramanian Suresh , Castelli Michael G. , Lerch Bradley A. , Allen Dana 
Published: March 2022

Abstract
The present study focuses on characterizing the fully-reversed fatigue behavior of unidirectional SCS6/Ti-15-3 composites. Fatigue tests were conducted at 800 ° F on 8 ply 0 ° laminates with fiber volume fractions ranging between 15% and 42%. Anti-buckling guides were designed to prevent sample buckling under compressive loading. Axial and transverse strain was monitored during static and fatigue loading to obtain a quantitative estimate of damage and plasticity in the material. The static tensile strength of this material (at 800 °F) with fiber volume fraction between 15% and 42% ranged between 136 ksi (937 MPa) and 252 ksi (1736 MPa) and the Poisson’s ratio between 0.29 and 0.38. Fatigue test results indicated that the life of unidirectional MMC was independent of fiber volume fraction when compared on a strain range basis. Results also indicated that there was very little change in axial stiffness and Poisson’s ratio in laminates with 35% and 42% fiber volume fraction. Lower volume fraction samples showed larger changes in properties under fatigue loading.
Interphase Strength of Ti-MMC Using a Localized Stress Approach
Authors: Tamin M. , Ghonem H. 
Published: March 2022

Abstract
This paper determines the fiber/matrix interphase shear strength in a titanium matrix composite using the knowledge of the load corresponding to onset of interface debonding in fiber push-out experiments. Finite element calculations employing an axisymmetric cylinder model of a fiber embedded in the matrix phase are utilized to calculate the interphase stress distribution along the fiber. A region of stress localization along the interface due to geometrical constraints of the fiber push-out test configuration is simulated. The interphase shear strength is defined as the peak of the shear stress localization along the fiber where initial debonding would occur. The calculated strength considers the contribution of the process-induced residual stress field as modified by geometrical constraints of fiber push-out test configuration. Results of the interphase strength obtained using the proposed localized approach are compared with those calculated assuming a uniform distributed shear stress along push-out fibers.
Mechanics of Polymeric Composites Exposed to a Constant Heat Flux
Authors: Tuttle Mark E. , Mescher Ann M. , Potocki Mark L. 
Published: March 2022

Abstract
An analysis procedure is presented which can be used to model the behavior of a polymeric composite panel when subjected to both external loading as well as the high heat flux levels associated with a fire. The procedure accounts for the elastic and viscoelastic-viscoplastic response, thermal gradients and thermal stresses, and pyrolysis effects. Predictions based on estimated properties for an E-glass/polyester composite panel subjected to a uniaxial tensile stress of 240 MPa and a 1-D heat flux level of 10 kW/m2 are presented. The predicted response is considered to be a reasonable representation of the expected behavior.
Stiffness Changes in Laminates Caused by Intralaminar Cracks and Shear Deformation
Authors: Varna Janis , Akshantala Nagendra V. , Talreja Ramesh 
Published: March 2022

Abstract
An experimental study has been conducted to study stiffness changes in laminates containing inclined (off-axis) plies. The class of laminates studied is glass-epoxy (0, ±θ4, 01/2)s with θ = 25, 40, 55 and 70. It is found that for θ &gt; 40 multiple cracks occur in the θ-plies while for θ &lt; 40 no cracks are found. However, for all θ angles the laminate moduli change. A continuum damage mechanics approach is used to calculate stiffness changes due to cracks. In the absence of cracks the shear modulus reduction in the θ-plies, determined from independent tests on a (±45)s laminate, is found to provide good prediction of the observed stiffness changes.