bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Analysis of Fuzzy Structure Parameters
Authors: Nagem Raymond J. , Stokes Ann W. , Selle Caitlin P.
Published: July 2023

An experiment is performed to investigate the vibration response of a simple beam with multiple oscillators attached along its length. Both single frequency and transient excitation are considered. The experimental results are compared with a model in which the discrete oscillators are replaced by a continuous distribution whose parameters are derived from the statistics of the masses, natural frequencies and locations of the attachments. Good agreement between the experimental and model results is obtained for the system frequency response. For the transient excitation, experimental results show that the attached oscillators produce an increase and a change in character in the effective decay rate of the beam response.
A Perturbation Solution for Forced Response of Systems Displaying Eigenvalue Veering
Authors: Pham Hoang , Ginsberg Jerry H.
Published: July 2023

This paper addresses the forced response analysis of systems whose eigenvalue loci veer when plotted against a system parameter. It builds on the study by Chen and Ginsberg [“On the relationship between veering of eigenvalue loci and parameter sensitivity of eigenfunctions,” ASME Journal of Vibration and Acoustics, 114, pp. 141–148 (1992)], which established a singular perturbation solution for the eigensolution as a function of a system parameter. It is shown here that if the position of the boundary depends on the system parameter, then the modes predicted by the earlier work will fail to satisfy geometric boundary conditions. This error is corrected by introducing a coordinate straining transformation. The modes obtained from the modified perturbation expansion are used as basis functions for a Ritz series expansion of the displacement. These steps lead to a highly efficient methodology for evaluating forced response for any value of the system parameter in the veering range. The development employs the classic two-span beam with a torsional spring at the intermediate pin support as the prototype illustrating the general steps. The parameter associated with the veering phenomena is the offset of the intermediate pin from the symmetric position. The adequacy of the solution is demonstrated by comparisons to results of an analytical Sturm-Liouville solution. The generality of the perturbation solution is further demonstrated by comparing the perturbation and analytical solutions for two other configurations featuring two-span beams: two simply-supported beams coupled by a weak torsional spring and a beam supporting an attached dead mass near its midspan.
Predicting Unsteady Aerodynamic Parameters From Airfoil Surface Pressure Measurements
Authors: Grace Sheryl Patrick
Published: July 2023

This paper explores the inverse unsteady aerodynamic problem for a flat-plate airfoil. The goal of the aerodynamic inversion is to calculate the parameters which describe the nature of the unsteadiness in the problem from information on the surface of the airfoil. Interest in the aerodynamic inversion stems from the fact that it, in conjunction with the much studied aeroacoustic inversion, offers a method for nonintrusive and nondestructive measurements. Using a linearized model, it is shown that only the component of the velocity disturbance normal to the airfoil can be recovered uniquely from the unsteady surface pressure: in addition, unique recovery of aeroelastic parameters describing heaving and pitching of the airfoil is feasible provided some information concerning the rotation axis is known.
The Origin and Implications of Higher-Order Cumulant Spectral Signatures in Hypoid Gear Trains
Authors: Hinich Melvin J. , Hixson Elmer L. , Sheehan Jack H.
Published: July 2023

This paper considers the origin and implications of higher-order (non-linear) cumulant spectral signatures generated by a hypoid gear assembly in a light utility van. This analysis demonstrates that the hypoid gear silencing problem is qualitatively and quantitatively different than the problems in gear design, both nominal and detailed, in particular:

• The production of sound by final drive gear trains is an extremely inefficient process; therefore, the vibration components which dominate sound generation are negligible quantities in typical gear design trade-offs. The usual silencing adjustments often shift but do not remove the offending source.

• Human hearing is acutely sensitive to the phase-coherent sinusoidal oscillations with modulated sidebands produced by hypoid gear trains. Modifications which reduce signature energy in a specific narrow band component may have no useful effect on perceived acoustic annoyance.

• Final drive measurements capture transient, stochastically modulated hypoid gear signatures confounded by highly correlated, non-Gaussian interference. Experimental design to explicitly measure the transient drive signals and the sources of correlated inference is essential for useful results.

• Emerging higher-order spectral analysis methods require long measurement ensembles to achieve appropriate resolution bandwidth and statistical convergence. Efficient data handling architecture for long, replicated ensembles is a pragmatic necessity.
Structural Response to Turbulent Wall-Pressure Fluctuations
Authors: Singer Bart A.
Published: July 2023

Results of a large-eddy simulation of a turbulent boundary layer over a rigid wall are used to provide detailed information of the time-dependent external pressure forcing on a thin-shell structure characteristic of an aircraft-fuselage panel. The autospectral density of the frequency response of the shell to the imposed forcing is computed with the finite element code MSC/NASTRAN. The results are compared to results obtained using simple models for the spatial distribution of the wall-pressure fluctuations.
Concurrently Engineered Active Composite Sandwich Panels
Authors: Koudela K. L. , Koopmann G. H. , Chen W.
Published: July 2023

The objective of this study was to design, fabricate, and test an active panel capable of significantly reducing the radiated sound power from a vibrating structure. To accomplish this objective, a cascaded flextensional actuator was embedded in a composite sandwich panel consisting of inner and outer E-glass/epoxy face sheets separated by a foam core where portions of the core were removed to accept a high performance actuator. The actuator consisted of a cascaded flextensional, mechanical amplifier driven by two, co-fired, multi-layered, piezoceramic stacks. The stack displacements were amplified by the cascaded flextensional to generate the levels of surface normal vibrations of the panel’s composite face sheets to produce the desired sound power reductions. A prototype active composite sandwich panel containing a single embedded cascaded flextensional actuator was fabricated and an experiment was conducted to evaluate its dynamic response. Dynamic finite element analyses were performed to simulate the experiment. Good correlation was obtained between the predictions and the experimental results. Final testing was conducted in air in a sound transmission loss facility to determine the levels of sound pressure reduction achievable with the prototype active composite sandwich panel. Up to a 25 dB reduction in sound pressure level was obtained over the frequency band of interest.
Electronic Hybrid Limiter (EHL) for Pump Displacement
Authors: Paoluzzi R. , Zarotti L. G. , Ruggeri M. , Fantuzzi C.
Published: July 2023

The paper reports upon numerical simulation tests carried out on a variable displacement axial piston pump equipped with multiple automatic controls. The swashplate control circuit includes two classical hydraulic stages with two tandem three way valves (the pressure compensator and the flow limiter) and a servovalve with digital control circuit acting as a hybrid torque or/and speed limiter. The dynamic response of the system is evaluated for both separate and combined control functions. The effect of changes in the digital control circuit is discussed with reference to the system response to various load demands with special emphasis devoted to the benefits induced by the use of fuzzy control logic.
A Survey of Hydraulic Fluid Analysis Methods
Authors: Norvelle F. Don
Published: July 2023

This paper is intended to provide the reader with a brief overview of the types of analyses that can be used to determine the condition of hydraulic fluids. Several types of contamination are discussed along with their effects on the system and components. Methods of detecting these contaminants are then presented. Finally, recommendations are presented for establishing a fluid analysis program. An appendix is included which lists standards and specifications dealing with hydraulic fluid condition analyses.
An Assessment of Simplified Inelastic Analysis Rules of the ASME Code
Authors: Chattopadhyay Somnath
Published: July 2023

The ASME Code specifies rules on low cycle fatigue evaluation for pressure vessels using elastic analyses. In low cycle fatigue, inelastic strains predominate and a knowledge of variation in strain is essential. However, a detailed inelastic analysis can be prohibitively expensive. Therefore the Code recommends performing linear elastic analyses using either modified material property or introducing a correction factor to account for plastic strain intensification. NB 3227.6 of the ASME Code specifies the use of a modified Poisson’s ratio in an elastic analysis for evaluating local thermal stresses when the maximum stress exceeds the yield strength of a material. NB 3228.3 of the ASME Code prescribes the Ke factor to be multiplied to the alternating stress for entering the design fatigue curve. Both these rules have been critically appraised and some possible improvements recommended.
Inelastic Analysis and Design Based on the p-Version of the Finite Element Method
Authors: Szabo Barna A. , Actis Ricardo L.
Published: July 2023

Until very recently, computer codes offering nonlinear capabilities were based on the h-version of the finite element method. In this paper we describe an algorithm and its implementation based on the p-version of the finite element method. The functionalities to be discussed are inelastic material behavior based on the deformation theory of plasticity and large displacements based on the Almansi strain - Cauchy stress formulation. The nonlinear computations are natural extensions of the linear analysis. In fact, linear analyses are viewed as the first step in performing numerical simulations of real physical systems only. The nonlinear computations are needed for controlling modelling errors. Concurrent control of discretization and modelling errors is described and illustrated by an example.
Development of a Generator Within a Bearing to Provide On-Board Power for Freight Cars
Authors: Samy Ram P. , Fuquen R. , French Michael L. , Varonis Orestes J. , Vuksta Ronald J. , Williams Samuel R.
Published: July 2023

The development of electronically controlled pneumatic (ECP) brake systems for freight trains assumes availability of on-board power. This paper describes recent efforts at The Timken Company to answer the question: “Is it possible to develop an electric generator that fits inside a railroad journal roller bearing and generates adequate power to charge an onboard battery in a freight train car?” Three-phase and single-phase permanent magnet generators were designed and developed to answer this important question and were tested successfully at Timken Research, Canton, Ohio. Some design challenges and test results are presented here. In addition to generating power, these devices can also provide information on the rotational speed (rpm) of the axle.
Simulation Test on Tread Shelling of Railroad Wheel
Authors: Sakamoto Haruo , Hirakawa Kenji , Toyama Kazuo , Nishimura Seiichi
Published: July 2023

Damages generated on railroad wheel tread are wear of tread and flange, heat and thermal cracks, spalling, and shelling. These damages are strongly affected by contact fatigue caused by contact rolling between wheel and rail. However, some of them are thermally influenced by skidding or tread braking. Such a thermal effect produces a variety of tread damages, and is a characteristic of damages due to contact fatigue in wheels.

To prevent such damages, it should be required to clarify the mechanism of damage occurrence or to test and reproduce the tread damages in laboratory. For investigation of new wheel or rail material to avoid such damages, laboratory tests creating the tread damages as appeared in service will be also desired.

In this report, simulation tests using the wheel testing machine and the contact fatigue tester in Sumitomo Metal Industries Ltd. are introduced to show how the tests make the damages on wheel tread and test specimen. In the simulation tests, reproduction of tread shelling has been focused on. This study also paid attention to the role of shear stress on contact fatigue, and the maximum depth of contact shear stress is compared for the tests performed.
Flexible Composite Tubulars
Authors: Walsh Thomas J.
Published: July 2023

Flexibility requirements for long length tubes (1000–10,000 meters) are driven not only by in-service environments, but also restrictions on the outer dimensions of a package destined for transport. Long lengths of tube are required to be spooled onto reels with small inner diameters. The ratio of tube outer diameter to the spooling diameter provides an estimate of the flexure strain. For example, a 50 mm OD tube spooled onto a 1 meter ID reel would impose 5% strain in the tube during storage. In extreme oilfield downhole environments, the flexible tube must not only survive the required extension, but also resist chemical attacks at elevated temperatures while maintaining pressure gradients across the tube wall and sustaining tensile loads.
Plane-Strain Near-Tip Fields for Wedge-Shaped Notches in Pressure-Sensitive Drucker-Prager Materials
Authors: Al-Abduljabbar A. , Pan J.
Published: July 2023

Plane-strain stress and slip-line fields near the sharp and round tips of wedge-shaped notches in perfectly plastic pressure-sensitive materials are investigated. The Drucker-Prager yield criterion is adopted to describe the material yielding behavior. Notch-tip stress and slip-line fields are first established for a sharp notch. Then the notch-tip stress and slip-line fields for a round notch tip are obtained. The results indicate that as the wedge angle increases, the opening stress and hydrostatic tension ahead of the tip of the sharp notch decrease. Also, as the wedge angle increases, the extent of the exponential spiral zone ahead of the round notch tip decreases and, consequently, the maximum opening stress and hydrostatic tension ahead of the tip decrease.
Tridimensional FE-Analysis of Stable Crack Growth in a CT-Specimen of a Structural Steel
Authors: Kolednik O. , Shan G. X. , Yan W.-Y. , Fischer F. D.
Published: July 2023

The crack growth in a plain sided Compact Tension specimen made of an annealed mild steel is simulated by a new tridimensional (3D) Finite Element analysis. The crack extension (Δa) is controlled by local Δa vs. load line displacement (vLL) curves originating from a multi-specimen JIC-test. The results of the 3D-analysis fit excellently to the measured load (P) vs. displacement and J-integral (J) vs. Δa-curves. It is shown that the local crack tip opening displacement at the advancing tip, CTOD, reaches a steady state value after a short transition region.

Further, a modified version of a two layer model (TLM), which was used in previous studies, is introduced. The TLM replaces the expensive 3D-analysis by two 2D-analyses, a plane strain analysis for the midsection region and a plane stress analysis for the near side surface region. The modified TLM uses two local Δa vs. vLL curves (for the midsection and the side surface) to control the crack extension in the two layers. The P-vLL- and J-Δa-curves of the modified TLM come very close to the results of the 3D-analysis.
An Integrated Research Approach to Attack Engine HCF Problem
Authors: Chang Jim C. I.
Published: July 2023

High Cycle Fatigue (HCF) has been the latest safety, operational and maintenance problem facing the jet engine community. HCF is caused by off-design operations of high performance aircraft having higher mean stresses on engine components from higher thrust design. The uncharacterized high cycle, low amplitude vibration from unknown unsteady fluid flow induced loading further complicated the stress and strain prediction on the engine components. The conventional fracture mechanics design approach has failed to quantify the HCF failure. The goal of this paper is to give a quantitative evaluation of the HCF problems, causes and research focuses.
Open-Hole Tension Fatigue Behavior of a Graphite/Bismaleimide at Elevated Temperatures
Authors: Gates Thomas. S. , Johnston William M.
Published: July 2023

This investigation utilizes the open hole tension (OHT) specimen loaded in tension-tension fatigue under isothermal, fixed frequency conditions. A range of load levels and temperature levels where chosen to assess performance. These loads and temperatures ranged from relatively benign conditions (low stress, room temperature) up through aggressive conditions (high stress, high temperature). Measurements were made on stiffness, damage accumulation, remaining strength, and changes in weight, and glass transition temperature (Tg).

Results from this work will help explain the roles of aging, load and fatigue in the performance of elevated temperature OHT as well as providing insights to the individual and synergistic contributions of each process. Experimental apparatus, test and data reduction procedures are outlined and explained.
Thermal Stresses in Unidirectional and Cross-Ply Composite Laminates: A 3-D Micromechanical Investigation
Authors: Dix Brian E. , Saigal Anil , Greif Robert
Published: July 2023

A micromechanical finite element model (FEM) has been developed using ANSYS to investigate the effects of temperature and cross-ply stacking on failure of graphite fiber-reinforced epoxy matrix (P75 graphite/934 epoxy) composites. Thermal residual stresses develop as a result of the difference in the coefficients of thermal expansion of the fiber and the matrix, and the operating and stress-free or cure temperature. It has been shown that these thermal stresses can be large enough to cause matrix cracking and possibly even laminate failure. Results from the 3-D micromechanical FEM are compared to those of the 2-D work, using laminated plate theory, done by Bowles and Griffin. A new curve of ultimate radial stress as a function of temperature was also developed. Using this curve, it is shown that the [0]s laminate model does not cross the failure criterion line when subjected to a delta temperature of −500°F. The [0/0/90/90]s model, however, reaches the ultimate radial stress at a temperature of about −15°F, assuming a stress-free temperature of 350°F. Bowles and Griffin’s ultimate radial stress curve, based on a single radial peaking factor, predicted the matrix failure at about 32°F. Further investigation of the model examines the effect of thermal loading on the matrix cracking.
A Comparison of the Timoshenko Theory and the Euler-Bernoulli Theory for Control of Laminated Beams
Authors: Aldraihem Osama J. , Wetherhold Robert C. , Singh Tarunraj
Published: July 2023

In this paper, the governing equations and boundary conditions of laminated beam smart structures are presented. Sensor and actuator layers are included in the beam so as to facilitate vibration supression. Two mathematical models are presented: the shear-deformable (Timoshenko) model and the shear-indeformable (Euler-Bernoulli) model. The differential equations for a continuous beam are approximated by utilizing finite element techniques for both models. A cantilever laminated beam with and without a tip mass is investigated to assess the validity and the accuracy of the two models when used for vibration supression. Comparison between the two models is presented to show the advantages and the limitations of each of the models. Since the Timoshenko beam theory is higher order than the Euler-Bernoulli theory, it is known to be superior in predicting the transient response of the beam. The superiority of the Timoshenko model is more pronounced for beams with a low aspect ratio. It is shown that use of an Euler-Bernoulli model to represent beam dynamics can lead to the design of an unstable controller.
Control of the Yarn Slip Interlace Deflector for a Textile Machine
Authors: Hunt Richard. M. , Beale David. G. , Nelms R. Mark.
Published: July 2023

As part of an industrial textile machine project, electrically controllable deflectors were needed for a yarn slip interlace device. The control system for the deflector needs to be robust and efficient to lower energy consumption and save space. A presentation of a simplified control system using solenoids with mechanical linkages along with details of the solenoid model is included.
Motion Control of a Space Tether at its Retrieval Phase
Authors: Natori M. C. , Iwasa Takashi , Higuchi Ken , Abe Masato
Published: July 2023

A linearized equation of tether motion is introduced by assuming the exponential change of tether length with respect to time and by adding small control deviation to the basic tether length, and the motion control by using optimum regulator is carried out. Some simulation results show very good control efforts. This control strategy is also applied to simulate the motion of a tethered mass on a special experimental equipment on ground, and successful motion control is demonstrated.
Optimal Control of a Two-Link Flexible Manipulator Along Specified Path
Authors: Farid M. , Lukasiewicz S. A.
Published: July 2023

In this paper a technique is proposed to find near time-optimal control solution of a two-link manipulator with torque and path constraints. Both links and joints are assumed to be flexible. The proposed approach is based on transforming the optimal control problem into an equivalent unconstrained optimum design problem using penalty function methods. Since in flexible manipulators the point for which the prescribed motion is specified and the application points of control torques are connected by elastic bodies, their inverse dynamics is non-causal. The proposed algorithm takes into account the non-causality of such systems via considering pre-actuation and post-actuation in the solution procedure.
Experimental Study of a Hydraulically-Amplified, High Displacement, Induced-Strain Actuators, Proof of Concept Demonstrator
Authors: Rusovici Razvan , Giurgiutiu Victor , Rogers Craig A.
Published: July 2023

A rotor blade trailing edge flap actuation device, HAHDIS (Hydraulically-Amplifed, High-Displacement, Induced-Strain Actuator), driven by two high-displacement induced-strain actuators (ISA), has been built and tested at the Center for Intelligent Materials Systems and Structures. The input displacements of the two solid-state piezoceramic ISA are hydraulically amplified and the linear output displacement is transformed, through a kinematic linkage, into the angular deflection of an aircraft servo-tab.

The paper presents the experimental tests and results. The data collected was processed to yield the electrical input energy and mechanical output energy as well as the displacement frequency response of the tab, over the 1–30 Hz frequency range. Good output force, work and displacement frequency responses were recorded over the frequency range of interest. Limitations in the electrical power supply capabilities were identified to be causing response losses at higher driving frequencies.
Coatings for Boundary Layer Control
Authors: Voropaev Gennady A. , Rozumniuk Natalya V. , May Carol L.
Published: July 2023

This study reviews research on boundary layer control coatings conducted initially by Dr. Gennady Voropaev and his team at the Institute of Hydromechanics, Kiev, and later in cooperation with Cortana Corporation, under the support of the Advanced Research Projects Agency. This article principally reviews findings associated with active control, but we summarize results for passive coatings in order to provide appropriate background. We document the existence of two mechanisms for drag reduction of an oscillating surface – 1.) a dynamic mechanism which is related to energy flux to or from the surface; and 2.) a kinematic mechanism which is related to Reynolds stresses. With an isotropic viscoelastic surface, where the phase of the surface disturbance is fixed at approximately π/2, drag reduction can occur only through the dynamic mechanism. However, in the case of an actively oscillating surface, where factors such as the amplitude of longitudinal and normal surface displacements, the phase difference, ϕ, the phase velocity, and the phase relationships between the surface and the external disturbance can be controlled, it is possible to determine conditions where both dynamic and kinematic mechanisms are operational and optimum, thus leading to a more significant reduction of friction drag.
Micro-Cavity Fiber Optic Sensors Embedded Into Laminated Composites for Impact and Impact-Induced Damage Detection
Authors: Chang Chia-Chen , Sirkis Jim
Published: July 2023

This paper describes the use of fiber optic sensors embedded into laminated [902/04/OF(0)/04/902] graphite /epoxy composites for low velocity impact detection and impact-induced damage assessment (The OF(0) denotes an optical fiber orientation of zero degree). The sensor system uses in-line fiber etalon (ILFE) sensors interrogated with path-matched differential interferometry (PMDI) and demodulated with a “single channel phase tracker”.

Initial impact tests comparing surface-mounted ILFE and resistance strain gages using an aluminum plate were favorable. The ILFE sensors were then embedded at the mid-plane of [902/04/OF(0)/04/902] composite plate subjected to transverse impact. The ILFE sensor response was compared to a resistance strain gage bonded to the back side of the specimen, comparison of the sensors showed that, as expected, higher transverse loads provided more dominant membrane stresses. An unexpected result of this series of tests was that the sensor embedded in the middle layer had higher survivability than the resistance strain gage bonded to the rear surface of the plate.

In a final series of experiments, copper coated ILFE sensors embedded in composite plates were investigated for their potential as damage sensors. The strain of the metal coated ILFE sensor and the load cell response were used to plot a hysteresis strain-load curve to assess the impact-induced damage. The result shows the ∼1 J impact energy starts to initiate the composite damage, and the hysteresis loop area is approximately proportional to the delamination area evaluated by X-ray radiographs. Finally, a control group of composite specimens without embedded optical fiber sensors was also tested under low velocity impact. X-ray NDE indicates that the embedded ILFE sensor does not alter the structural integrity based on the macro-scale observations.
Criticality-Based Maintenance: Prioritizing Maintenance Activities for Optimum Equipment Reliability
Authors: Ciliberti V. Anthony
Published: July 2023

Criticality-Based Maintenance (CBM) is a prioritized approach to the maintenance of process equipment in the oil, gas, and petrochemical processing industries. CBM equally weighs process and safety issues in establishing criticality, which gives companies a return on investment for mechanical integrity efforts while establishing compliance with governmental regulations. This approach optimizes the effectiveness of mechanical integrity programs by focusing on the most important, or critical equipment items.

CBM uses a criticality ranking process which is very similar to the methodology used in a process hazard analysis study. All process equipment items are evaluated and then each is given a relative value in an overall criticality hierarchy. With all equipment evaluated for criticality, prioritization of maintenance activities begins.
A Basis for Determining Fill Times for Dry Fire Lines in Highway Tunnels
Authors: Harris Kenneth J.
Published: July 2023

This paper provides a theoretical basis for the fill time of a single long pipeline utilizing the Euler equations for fluid flow and developing the differential unsteady flow equations. These equations are then integrated numerically to provide the theoretical fill time for a particular series of conditions.

Theoretical models can only be analyzed for relatively simple systems. Pipeline systems in tunnels are subject to complex geometries including horizontal and vertical curves, varying size lines, multiple feed points, pumps, and multiple flow paths. Many commercial software packages are available to assist in the steady state analysis, i.e. operating conditions, of pipeline networks under these conditions. These same tools can be adapted for unsteady flow conditions, such as line filling, by dividing the one system into a series of systems. A comparison of the fill time estimates using this method shows reasonable correlation to that using an unsteady flow analysis.
Approaches to Accident Analysis in Recent U.S. Department of Energy Environmental Impact Statements
Authors: Mueller Charles , Folga Stephen , Nabelssi Bassel
Published: July 2023

A review of accident analyses in recent U.S. Department of Energy (DOE) Environmental Impact Statements (EISs) was conducted to evaluate the consistency among approaches and to compare these approaches with existing DOE guidance. The review considered several components of an accident analysis: the overall scope, which in turn should reflect the scope of the EIS; the spectrum of accidents considered; the methods and assumptions used to determine frequencies or frequency ranges for the accident sequences; and the assumptions and technical bases for developing radiological and chemical atmospheric source terms and for calculating the consequences of airborne releases. The review also considered the range of results generated with respect to impacts on various worker and general populations. In this paper, the findings of these reviews are presented and methods recommended for improving consistency among EISs and bringing them more into line with existing DOE guidance.
The Grate Debate
Authors: Brickman Dennis B. , Barnett Ralph L.
Published: July 2023

The grate debate focuses on two important aspects of grating design, flow function and barrier guarding. In general, it is impossible when utilizing grating to simultaneously achieve the required function and adequate human protection. This paper outlines the leading philosophical positions and technical theories of barrier guarding that are required to resolve this risk-utility dilemma.
Building on Small Scale Pilots: Field Testing the Necessary and Sufficient Closure Process
Authors: Short David W. , Parzyck Dennis C.
Published: July 2023

After months of research, discussion, and effort, a process for arriving at Work Smart Standards sets was accepted for field testing by the DOE Department Standards Committee. This Necessary and Sufficient Closure Process was applied at nine locations throughout the DOE complex, locations chosen to offer a wide variety of sites and work scopes. The Committee wanted proof that reliable Work Smart Standards sets could be selected consistently across the range of DOE sites, facilities, and work activities. The Committee got the evidence it needed. Whenever and wherever a Pilot demonstration followed the process rigorously, a reliable Work Smart Standards set was selected, confirmed, and approved. Indeed, the results from these “Pilot demonstrations” were so promising that fifteen “Second Round” Work Smart Standards applications are underway, with more in the wings. Results including increased safety, reduced risk, costs avoided, and costs saved are already significant.
Predicted Dynamic Strength and Durability of a Network Interface Unit (NIU) Enclosure
Authors: Uschitsky M. , Suhir E. , Shepherd L. , Lambert W. R. , Zimmerman M. A.
Published: July 2023

The Network Interface Unit (NIU) enclosures might be subjected, during the 10–15 years of their projected service life, to various dynamic loads. They will experience also harsh environmental effects. In this study, we analyze the dynamic strength and long-term reliability of a thin-walled NIU enclosure made of a preweathered polycarbonate. Dynamic response of the enclosure to shock loading and fracture due to harsh weathering conditions are evaluated, and a methodology for the prediction of the long-term strength of the material is developed. The obtained theoretical results are in good agreement with the available experimental data. The results of the study can be used in the structural analysis and physical design of NIU enclosures.
Separation of a Molten Axisymmetric Solder Joint
Authors: Goldmann Lewis S.
Published: July 2023

It is often critical in the processing of BGA or flip chip solder joints to be able to predict the tensile force or displacement at which a molten solder joint breaks apart. Among processes which could rely on this information are component rework, joint stretching for enhanced reliability and two-sided joining. This paper presents a physical model to describe separation and develops heuristic equations which describe the phenomenon.
Optimal Cryopreservation Protocol Design for Pancreas Islets
Authors: de Freitas Robson Cintra , Diller Kenneth R.
Published: July 2023

A thermal protocol for the cryopreservation of human pancreas islets was designed based on optimizing the dual criterion of minimizing the probability of intracellular ice formation and minimizing the volumetric excursions experienced by the islets during subzero temperature processing. The results indicate that a cooling rate of 1°C/min between the temperatures of −8°C and −40°C meets the optimization criterion for islets preequilibrated with a 2M DMSO cryoprotective additive (CPA).
Enhanced Vitrification of Cryopreservation Media in the Presence of Microwave Irradiation
Authors: Jackson Thomas H. , Ungan Aydin , Critser John K. , Gao Dayong
Published: July 2023

This paper reports preliminary findings on the effect of microwave radiation on ice crystal formation. This experiment hypothesized that electromagnetic radiation could interact with dipolar H2O molecules in such a way that crystallization phenomena may be disrupted (or possibly enhanced). Test samples consisted of a series of ethylene glycol solutions. A microwave resonant cavity was used to provide an intense oscillating electric field. Solutions were simultaneously exposed to this electric field and cooled to −196°C by immersion in liquid nitrogen. Control samples where similarly submerged in liquid nitrogen but without the microwave field. The amount of ice formation was determined by analysis of digital images of the samples. It was found that cooling in the presence of an intense microwave field could significantly enhance vitrification during cooling of aqueous solutions. This study indicated that ice formation could be reduced by up to 66% in 4.5 molar solutions of ethylene glycol solutions.
Determination of Lung Dysfunction Using a Model for Gas Exchange (Theory)
Authors: Montoya J. Patrick , Peng Ching-An , Yang Wen-Jey , Bartlett Robert H.
Published: July 2023

In an effort to quantitate lung dysfunction in patients with respiratory failure, a technique is developed in which a mathematical model of lung gas exchange is used in conjunction with measured data readily obtainable from patient undergoing respiratory support. The whole lung is modeled as one or more homogeneous gas exchange alveolo-capillary units in which the conditions known to cause reduced gas transfer can be quantitated: diffusion impairment, ventilation/perfusion mismatch, venous to arterial blood shunt, and large ventilatory dead space.
Effect of Tissue Chromophore on the Mechanism and Dynamics of Pulsed Laser Ablation
Authors: Venugopalan V. , Nishioka N. S. , Mikić B. B.
Published: July 2023

The effect of chromophore targeting on the mechanism and dynamics of pulsed laser ablation of soft biological tissues is discussed. We argue that if mechanical stresses generated by thermoelastic expansion are insufficient to achieve tissue fracture and the delivered laser energy is confined to the site of absorption, material removal is governed by the thermodynamics of chromophore decomposition. Specifically, if water is the dominant chromophore, the ablation process will be explosive because heated water undergoes a process of explosive boiling which strains and fractures the tissue to achieve material removal. In contrast, if structural proteins of the tissue are targeted directly, the mechanical integrity of the tissue can be compromised during irradiation and results in material removal consistent with a process of rapid surface vaporization.
Scaling Blood Flow Rate in the Rat Spinotrapezius Muscle
Authors: Song Ji , Xu Lisa X. , Weinbaum Sheldon , Lemons Daniel E.
Published: July 2023

In this study, appropriate biological scalings were established based on our experimental measurements of the tissue weight, vessel diameter and blood flow rate in rat spinotrapezius muscle under the normal, vasoconstricted and vasodilated conditions. Based on the measured data in the spinotrapezius of rat of different weight, the scaling laws for geometry and flow in the same organ were analyzed for the first time. Using these relationships, blood flow rates within microvessels of different generations in spinotrapezius muscle can be extrapolated over a wide range of muscle weights. This provides an opportunity to predict the blood flow in large microvessels where it is difficult to make direct measurements using optical methods due to the high blood flow rate and the thickness of the tissue and vessel wall. Further, the allometric relationship between the blood flow rate and vessel diameter indicates that the shear stress at the vessel wall is approximately constant which follows the theoretical minimum work principle.
Penetration Depth Control With Dual Frequency Ultrasound
Authors: Moros Eduardo G. , Fan Xiaobing , Straube William L.
Published: July 2023

Several groups are developing heating devices for simultaneous thermoradiotherapy to enhance thermal radiosensitization. One of our designs is an applicator for induction of superficial hyperthermia which is also compatible for concomitant operation with a linear accelerator. The dual-frequency system (DFS) design uses parallel-opposed linear arrays and a scanning dual-face reflector. The scanning reflector deflects and distributes, under computer control, the waves coming from the arrays toward the target. The prime design objectives for this design were: 1) compatibility with a linear accelerator; 2) sufficiently non-perturbing and non-attenuating to allow use of medical electron beams; 3) improved lateral conformability of power deposition; and 4) penetration depth control. Technical feasibility, lateral conformability and design optimization studies for a similar one-array system have been previously reported. Here, an acoustic model was developed to investigate the controllability of penetration depth of the DFS design. Results showed that by varying the power outputs from the low and high frequency arrays, the depth of the 50% isopower contour can be controlled over a range of 3 cm. Thermal simulations using the bioheat transfer equation were also performed which demonstrated corresponding changes in the depth of therapeutic isotherms over a 2.5 cm range for different low-to-high frequency power ratios. The results suggest that the DFS may be suitable for heating (sequentially or simultaneously with external beam radiation) extensive superficial tumors, where the distal tumor margin varies over the extent of the tumor, and where underlying bony structures and/or gas cavities are present such as in chest-wall lesions.
A Study of Bubble Behavior and Boiling Heat Transfer Enhancement Under Electric Field
Authors: Oh Si-Doek , Kwak Ho-Young
Published: July 2023

The effect of d.c electric field on nucleate boiling heat transfer for refrigerants, R11, R113 and FC72 was investigated experimentally in a single-tube shell/tube heat exchanger by using the temperature control method of wall superheat. Also the behavior of bubble under nonuniform electric field produced by wire electrodes was studied by numerical calculation. For R11, the Electrohydrodynamic (EHD) enhancement for boiling heat transfer was observed for all ranges of the wall superheat tested. However, the enhancement in boiling heat transfer disappeared if the wall superheat exceeds 13°C for R113 and no electric field effect on the boiling heat transfer was observed for FC72. An application of approximately 5kV was enough to eliminate the boiling hysteresis for R11 and R113. Numerical study has revealed that the bubbles are forced away from the heating surface and toward the electrostatic stagnation point by the dielectrophoretic force. Such modified bubble motion turns out to promote the boiling heat transfer if one use proper electrode configuration.
Turbulent Friction Factor for Two-Phase: Air-Viscoelastic Fluid Flows Through Horizontal Straight Circular Tubes
Authors: Rao B. K.
Published: July 2023

Fully developed turbulent isothermal Fanning friction factors for air-viscoelastic fluid flows through a horizontal pipe were experimentally measured. The viscoelastic fluids studied were aqueous solutions of polyacrylamide at three different concentrations (100, 200, and 500 wppm). The two-phase friction factor data were correlated in terms of the apparent Reynolds number defined based on the effective viscosity for gas-liquid mixture. Over a range of the apparent Reynolds number from 104 to 105, the simpler homogeneous model used was found to be accurate enough for engineering prediction of friction factor for air-viscoelastic fluid flows through straight pipes. A correlation for the prediction of air-viscoelastic two-phase turbulent friction factor is proposed.
Analysis of Tombstoning Phenomenon During Reflow
Authors: Qi Quan , Mahajan Roop L.
Published: July 2023

A dynamic model is established to investigate tombstoning phenomenon of passive SMT components during reflow. This model consists of three dynamic equations for the motion of the component and four nonlinear algebraic equations for area conservation, constant curvatures for solder fillets and solder height-length relations. The formulation neglects the gravity effect in the solder. It is shown that formation of tombstoning depends on a combination of parameters such as component geometry, pad sizes, gap size between pads, molten solder volume and properties, and contact angles. For some values of these parameters encountered in practice, tombstoning can take place. For a given component, this model may be used to improve solder pad and stencil designs to avoid tombstoning.
Microstructural Effects in Precision Hard Turning
Authors: Chou Y. Kevin , Evans Chris J.
Published: July 2023

Precision hard turning provides an alternative to grinding in some finishing applications. Rapid tool wear, however, remains a bottleneck to the process being economically viable. This experimental study reports microstructural effects on cubic boron nitride (CBN) tool wear in finish hard turning. Results indicate that; 1) carbide sizes of the workpiece have significant effects on tool wear; 2) wear resistance monotonically increases with decreasing CBN grain size; and 3) in finish turning with low CBN content tools, the governing wear mechanism is fine scale attrition by microfracture and fatigue. A powder metallurgy M50 bar hard turned using an ultrafine CBN grain tool shows flank wear less than 45 μm VBmax after 6.2 km cutting distance; wear rate equals to 3.1 μm/km. Surface finish is better than 80 run Ra.
An Analytical Finite Element Model for Predicting Three-Dimensional Tool Forces and Chip Flow
Authors: Strenkowski John S. , Lin Jong-Cherng
Published: July 2023

In this paper, a model of three-dimensional cutting is developed for predicting three-dimensional tool forces and the chip flow angle. The approach consists of coupling an orthogonal finite element cutting model with an analytical model of three-dimensional cutting. The finite element model is based on an Eulerian approach, which gives excellent agreement with measured tool forces and chip geometries. The analytical model was developed by Usui, in which a minimum energy approach was used to determine the chip flow direction.

The model developed by Usui required orthogonal cutting test data to determine the tool forces and chip flow angle. In this paper, the finite element model is used to supply the orthogonal cutting data for Usui’s model. With this approach, a predictive model of three-dimensional cutting can be developed that does not require measured data as input. Cutting experiments are described in which excellent agreement was found between measured and predicted tool forces and chip flow angles for machining of AISI 1020 steel.
Numerical Modeling of a Spin-Casting Process
Authors: Chen Jim S.-J. , Dean Adam , Rajagopalan Srini
Published: July 2023

In this paper, numerical modeling of heat transfer in a spin-casting process is analyzed. Effects of interface heat-transfer coefficient. undercooling and finite ribbon thickness on the solidification behavior are considered. The results are compared with analytical solutions of similar conditions. The temperature distribution across the wheel and ribbon is examined. In spin-casting of TiAl ribbon on a Mo wheel, the solid/liquid interface velocities in the range of 0.1–1.0 m/s and cooling rates in the range of 1–5 × 105°C/s are obtained. In the presence of undercooling, the solid/liquid interface velocity increases to 10 m/s. Moderate to high undercooling results in partial remelting of the ribbon.
Integration of Control and Information System for Automated Manufacturing Systems Based on Object-Oriented Approach
Authors: Chen Kai-Ying , Lu Shui-Shong
Published: July 2023

In this paper, an object-oriented design method is proposed for the control software design of an automated manufacturing system. This object-oriented approach is based on three popular modeling tools — IDEFO, entity-relationship diagram (ERD) and Petri-Net. Firstly, IDEFO, ERD and Petri-Net models for manufacturing systems are constructed. Some transformation rules are found between these models and object-oriented model. Finally, simulation and control software are coded based on object-oriented model. As an example, application of this method to an automated manufacturing cell are illustrated.
Information Management and Presentation in Business Process Improvement: A Case Study
Authors: Chatterjee S.
Published: July 2023

This paper presents a case study in business process improvement for a tier-one automobile parts supplier. The organization was faced with of lack of part inventory accuracy resulting from an unstructured process of information recording, storage, dissemination, and presentation on manufactured components and finished assemblies. A systems approach was utilized in developing an improved process for rectifying inventory inaccuracy. A redesigned system for information collection, storage, dissemination, and presentation was developed and implemented. Significant improvements were observed in the overall process after the implementation.
Integer Programming Approach as an Alternative to the Quality Loss Function in Tolerance Design
Authors: Feng Chang-Xue Jack , Kusiak Andrew
Published: July 2023

The Taguchi quality loss function provides an analytic tool for considering the quality cost in tolerance design at the product design stage. But it fails to consider the manufacturing cost and design constraints. In addition, it is difficult to determine the quality loss constant A in the quadratic function. This research demonstrates that the quality loss cost is only a small portion of the total cost if the manufacturing cost is considered. An alternative method is provided to ensure the required level of quality and avoid using the confusing constant A. A numerical example illustrates the quality loss function and the proposed approach.