bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Integration of Haptic User Interface in CAD Systems
Authors: Stewart Paul , Chen Yifan , Buttolo Pietro
Published: March 2022

The potential of haptic interfaces applied to product design is of growing interest to the automotive industry. However, the full potential of any technology is best realized when it is integrated effectively into the product development environment and process. For most every large manufacturing company this means integration into a commercial CAD system. This paper addresses the fundamental concerns arising from an industrial CAD environment, and highlights the benefits of direct haptic interaction with the CAD model. Design fidelity, a concern of most product development applications, and its relationship to haptics is discussed. The advantages of interacting directly with mathematical CAD models, such as NURBS, are explained. Subsequently, numerical methods and procedures to haptically render NURBS surfaces are discussed. And finally a description of the fully immersive prototype CAD system recently developed at Ford which allows a designer to both see and touch CAD surfaces during product development is provided.
Cooperative Object Manipulation in Virtual Space Using Virtual Physics
Authors: Noma Haruo , Miyasato Tsutomu
Published: March 2022

This study focuses on precise and natural cooperative object manipulation by multi-users in a virtual space. We first considered the advantages of direct virtual object manipulation by multi-users’ hands and the necessity of mechanical restriction between them. Here, we applied an illusion between the visual and haptic sensations to create realistic cooperative manipulation when using VR devices that cannot simulate entire physics. We introduce two virtually-expanded physical laws: “virtual mechanical equilibrium on a rigid object” and “exclusive object arrangement”. We have built a trial system with two hands according to our proposed design, and the experimental results demonstrate the effectiveness of our proposed method for both-hands manipulation. This method’s aim is to allow users to exchange intentions of manipulation through haptic and visual channels by using limited VR devices.
Getting a Feel for Dynamics: Using Haptic Interface Kits for Teaching Dynamics and Controls
Authors: Richard Christopher , Okamura Allison M. , Cutkosky Mark R.
Published: March 2022

Low cost, single-axis force reflecting joysticks were used to teach students about electromechanical systems, dynamics and controls. The students assembled the devices from kits, tested and analyzed them, and used them to interact with computer models of dynamic systems. The devices helped students to appreciate such phenomena as equivalent inertia, friction and the effects of changing control system parameters. They also generated high enthusiasm among the students, particularly when used in cooperative “haptic video games” at the end of the course.
Detection of Real and Virtual Fine Surface Features With a Haptic Interface and Stylus
Authors: West Aaron M. , Cutkosky Mark R.
Published: March 2022

In this paper we discuss the results of displaying fine surface features using a haptic interface. A stylus was connected to a haptic interface and configured so that users could explore real and virtual surfaces using the same apparatus. The surfaces consisted of sinusoidal profiles with amplitudes of 0.01–10 mm and with frequencies of 1–20 cycles over a length of 85 mm. Subjects were asked to explore the surfaces at will and count the number of waves detected. When exploring physical profiles, tests were conducted using a stylus with friction and a “frictionless” stylus with a roller. For comparison, tests were also conducted using the subjects’ fingertips instead of a stylus for physical surface exploration. Our results show that subjects’ perceptions of sinusoidal features on virtual and physical walls are qualitatively similar. At spatial frequencies of 0.24 cycles/mm and greater, the ability of humans to accurately count virtual and physical waves was also similar, despite the limited stiffness and bandwidth of the haptic interface. The results provide insight for the display of fine features such as ridges or grooves on a virtual wall.
Sticking to the Point: A Friction and Adhesion Model for Simulated Surfaces
Authors: Chen Jun , DiMattia Christopher , Taylor Russell M. , Falvo Mike , Thiansathaporn Pichet , Superfine Richard
Published: March 2022

This paper describes the development and current status of our combined physics-based model to simulate friction, compliance and adhesion on surfaces using a haptic interface. We use points on the surface to which a simulated stylus sticks until enough force is exerted to break free. The model is inherently stable at all transitions (to/from kinetic/static friction and adhesion) because the force model does not change between modes of attachment. We also present our earlier, unsatisfactory attempts and the problems they had. We describe an application that uses the model and the physics behind it.
A Novel Mechanical Transmission Applied to Percutaneous Renal Access
Authors: Stoianovici Dan , Cadeddu Jeffrey A. , Demaree Roger D. , Basile Stephen A. , Taylor Russell H. , Whitcomb Louis L. , Kavoussi Louis R.
Published: March 2022

This paper presents a radiological guidance method and robotic system designed to facilitate renal surgical procedures. Combines the guidance procedure normally employed by practicing surgeons with a simple and cost-effective needle injection device. The needle injector exhibits an extremely low radiological profile while providing actuated needle motion. The system can be easily utilized by urologic surgeons and can be readily adaptable to any operating room.
Dynamic Control of a Four-Axis, Electrohydraulic Knee Simulator
Authors: Maletsky Lorin P. , Hillberry Ben M.
Published: March 2022

Joint simulators have been used frequently to generate meaningful data on prosthetic wear, bone kinematics, and ligament function. The complex and high loads associated with the knee joint have prompted the development of a wide variety of knee simulators. A four-axis knee simulator was developed at Purdue University that simulates the tibio-femoral and patello-femoral forces by four externally applied loads at the hip and ankle at the hip and ankle. The Purdue Knee Simulator has repeatedly demonstrated the ability to generate realistic prosthetic wear and kinematic motions similar to the natural knee. The operation of the Purdue Knee Simulator, the generation of input profiles, and a brief review of some of the research completed utilizing this machine is presented.
Control of a Hopping Apparatus
Authors: Larin Vladimir B.
Published: March 2022

A problem of control of the model of a one-legged hopping apparatus is considered. Relations determining a program mode of movement are received. The problem of synthesis of system of stabilization is reduced to periodic linear quadratic problem. Example of synthesis of control system of hopping apparatus are considered and the results of simulation of starting processes of these apparatus are presented.
Performance-Based Selection of PD Control Gains for Servo Systems With Actuator Saturation
Authors: Goldfarb Michael , Sirithanapipat Taweedej
Published: March 2022

Servo-control is a common control problem that typically involves a system characterized by torque input and angular position output. A direct-drive robot, for example, is a coupled and typically nonlinear servo-control problem. One means of closed-loop control of a servo-system is proportional-derivative (PD) control. PD control is passive in character and thus stable, and since it can be easily implemented in analog form, the stability is not compromised by computational time delays. A significant issue in implementing PD control on a servo-system is the selection of the control gains. Linearizing a nonlinear servo-system and utilizing linear analysis methods suggests best performance is achieved at maximum possible gain. Maximum gain, however, drives the actuators into saturation, which renders the system nonlinear and the linear analysis invalid. This paper investigates the effect of actuator saturation on servo-system tracking performance by formulating a frequency-based equivalent to the linear system -3dB bandwidth. The proposed method utilizes a series of band-limited pseudo-random tracking inputs to characterize the “bandwidth” of a nonlinear system. Numerical analysis based on this method shows that, for a servo-system that exhibits actuator saturation, the optimal tracking performance is not achieved at maximum gain. Instead, performance improves up to a given gain, then begins to recede as the gain is increased further. The analysis also shows that avoiding actuator saturation to ensure linear behavior significantly sacrifices system performance. The performance characterization scheme is illustrated by an example of a servo system with actuator saturation. The methodology is also compared with linear analysis techniques, and the two shown to be well-correlated for a linear system.
Adaptive, Backstepping Control of a Magnetically Levitated System
Authors: Green Scott A. , Craig Kevin C.
Published: March 2022

This paper presents an evaluation of the adaptive, backstepping control technique applied to a single-degree-of-freedom, magnetic levitation system. Comparisons are made between a linear compensator and a backstepping compensator for step changes in the commanded position of levitation. Performance is evaluated based upon percent overshoot, settling time, steady-state error, and robustness to variations in levitated mass. The adaptive, backstepping compensator is found to achieve superior performance over the linear compensator when subjected to variations in both levitated mass and commanded position. By investigating the performance of this emerging technique known as backstepping under these inherently nonlinear conditions, it is intended to determine the feasibility and capabilities of this approach for practical applications to magnetic levitation systems.
Control of a Class of Nonlinear Systems Subject to Periodic Exogenous Signals
Authors: Alleyne Andrew G.
Published: March 2022

This paper examines the control of Single-Input, Single-Output Feedback Linearizable nonlinear systems that are either (i) subject to periodic disturbances or (ii) tracking periodic reference trajectories. The key concept is the straightforward combination of well known Differential Geometric techniques with the Internal Model Principle resulting in a nonlinear repetitive control strategy. A formulation is presented for the case of Input-State Linearizable and Input-Output Linearizable systems in continuous time. The potential benefits of the nonlinear repetitive controller are given. It is shown that while the standard nonlinear control techniques can be made robust to known disturbances, the nonlinear repetitive technique has desireable charateristics in that it does not require knowledge of the disturbance magnitude and does not need an increased loop gain to accomplish robustness. The procedure is applied to a numerical simulation example with the resulting benefits being clearly shown.
The Design of Quality Engineered Control Systems
Authors: Nwokah O. D. I. , Happawana Gemunu S. , Afolabi Daré
Published: March 2022

Every optimization based engineering design produces a quality metric which as a function of the tolerance parameters, is structurally stable but not generic. This can lead to a severe loss of performance (catastrophes) under a smooth change in the tolerance parameters. This paper gives an exposition of how norm based optimal control methods naturally lead to performance catastrophes, as well as an alternative systematic loop shaping design methodology which corrects the problem.
Modeling and Error Analysis for Assessing Spindle Radial Error Motions
Authors: Tu Jay F. , Bossmanns Bernd , Hung Spring C. C.
Published: March 2022

The rotating accuracy of a machine tool spindle directly affects the roundness of machined parts. Commonly, a precision arbor and one or two probes are used to inspect the spindle axis error motion. When a reference precision arbor is not available or when the spindle error motion is in the same order of magnitude as the accuracy of the reference arbor, it is imperative to separate the roundness error of the reference arbor from the spindle error. One of the most widely used method is the three-probe method. This paper presents an exact model and in-depth error analysis for the conventional three-probe method. The results show that contrary to conventional wisdom that a precise arbor is not needed with the three-probe method, the arbor accuracy should be at least ten times better than that of the axis motion. To reduce inaccuracy in the converted axis motion and arbor contour, it is also suggested that the mounting error of the probes should be less than one-fiftieth of the size of the axis motion and the arbor size. The exact geometric model developed in this paper can also be extended to analyze the precision aspect of other methods.
Adaptive Controller for a Centerless Grinding Process
Authors: Kurfess Thomas R. , Yim Sungshik
Published: March 2022

This work proposes an approach using a Kalman filter and an adaptive controller to control the product size in centerless grinding. Plant parameters are estimated in real time by a weighted recursive least squares technique. The Kalman filter receives these parameters, along with the current input and output signals of the plant, to estimate the main trend of the plant output signal. An adaptive controller uses this information and the estimated main trend signal to generate a control signal. However, this linear control signal cannot be directly used to control the product size in a grinding process because of plant nonlinearities. Thus, the linear control signal is converted to the appropriate compensation signal used by the machine tool.
The Role of Electric-Current Induced Heating in Damage Evolution at the Crack Tip in Thin Film Conductors
Authors: Bastawros Ashraf -F. , Kim Kyung -S.
Published: March 2022

The time-dependent temperature distribution induced by electric-current heating in a double edge-cracked, unpassivated thin aluminum or gold film interconnect lines is monitored using a high-resolution infrared imaging system. A pure aluminum or gold film of 0.2 micron thickness is deposited by high-vacuum evaporation coating and patterned into test structures of varying widths. The operative mechanisms of mass transport are assessed in view of the monitored temperature profile. The pre-cracked aluminum film showed fine crack growth toward the positive electrode, which originated from the initial crack tips. The crack-tip temperature was close to melting, during propagation. A hot spot was formed afterward between the two elongated cracks and led to failure. The crack growth generated a backward mass flow toward the negative electrode. The gold film showed a different pattern where the original cracks propagated toward each other with a slight tilt toward the negative electrode. The tip temperature was lower than the melting temperature.
Penetration Performance of the Train of Solid and Hollow Disks
Authors: Lee M.
Published: March 2022

The penetration performance of homogeneous disk (μ = 0) and thick walled disk (μ < 0.5) projectiles are investigated numerically for length-to-diameter ratio (L/D) of 1/8 and 1/4, where μ is the ratio of inner to outer diameter of a disk. Penetrations of tungsten alloy projectiles up to 4 successive solid disks (SD) and hollow disks (HD) with spacing of 1.5, 2 and 3 diameters into rolled homogeneous armor (RHA) at 2.6 km/s were simulated with a finite difference nonlinear wave propagation program. The most obvious results from the calculations are that even at 2.6 km/s the total penetration of a 4-segmented projectile can not be obtained simply be multiplying the depth of a single disk by four, especially for L/D = 1/8. Although HD may be more efficient, in terms of mass, than SD of equal outer diameter, it is observed that precursor or jet interacts with a train of spaced HD. This interaction significantly reduces the penetration performance, which was also measured in the long tubular projectiles. The degradation in total penetration becomes worse as μ increases. For HD of L/D = 1/4 case, the degradation in penetration becomes less since the effect of the interaction of jet with successive disks is relatively small.
The Influence of Material Damping on Flexural Vibration of Thick Cylinders
Authors: Hamidzadeh Hamid R. , Afolabi Dare
Published: March 2022

Harmonic vibrations of thick visco-elastic, infinitely long, circular cylinders subjected to boundary stresses are investigated. The cylinder is assumed to be homogeneous, isotropic, and linearly visco-elastic. The inelastic behavior of some metallic materials leads to dissipation of energy in the medium. The governing equation of motion is developed using modified theory of elastodynamics. The material damping is allowed using complex elastic moduli for the medium. Frequency responses for radial, tangential and axial displacements, as well as stresses at any location, are formulated using potential functions. The responses are computed for different circumferential and axial wave numbers for a given ratio of thickness to radius of the cylinder. The frequency range is extended to include five normalized resonant frequencies. The resonant frequency and loss factor for each mode are extracted using a circle-fit procedure in conjunction with finite difference analysis. The resonant frequency is deduced by estimating a maximum rate of sweep on the circle-fit and the loss factor is determined using selected data points on both sides of the resonance. Computation is performed to determine the effect of material loss factor on the overall damping effectiveness for the structure. Analysis was conducted by estimating resonant frequencies and modal loss factors for several circumferential and thickness to wavelength numbers.
An Investigation of the Effects of Multiple Parameters on the Fatigue Crack Growth Behavior of Ti-6Al-4V
Authors: Foster Michael , Soboyejo Alfred , Katsube Noriko , Dubey Sharmistha , Soboyejo Wolé
Published: March 2022

The effects of specimen thickness and positive stress ratio on the fatigue crack growth behavior of Ti-6Al-4V are discussed in this paper. Fatigue crack growth rates are shown to increase with increasing stress ratio. Stress ratio is shown to have a strong effect on fatigue crack growth behavior. However, for the range of specimen thicknesses examined in this study, the fatigue crack growth rates are shown to not be strongly affected by specimen thickness. A single intrinsic fatigue crack growth rate curve is obtained when the fatigue crack growth rates are plotted against the effective (closure-corrected) stress intensity factor range. Multiparameter extensions to the Paris law are also presented for the combined assessment of the effects of specimen thickness, stress ratio, and crack closure on the fatigue crack growth behavior of Ti-6Al-4V.
On the Performance vs. Energy Consumption Tradeoff With Semi-Active Vibration Control Using an MR-Fluid Damper
Authors: Lee Jin Kyoo , Clark William W. , Kim Sung Hwan
Published: March 2022

This paper discusses the issue of seeking reduced energy requirements of a magnetorheological (MR) fluid damper for vibration control through semi-active methods, without suffering unacceptable losses in performance. An experimental study is presented in which an MR fluid damper is used to suppress vibrations in a simply-supported beam under harmonic excitation. Two semi-active control approaches are compared to the “fully-on” control situation. The results show that the MR damper can be activated only for part of the vibration cycle and still provide significant vibration suppression.
Actuator Bearing Greases: Their Effect on Aerosol Contamination in Disk Drives
Authors: Prater Walter , Stone Garvin
Published: March 2022

Head stiction problems have driven the search for new actuator bearing greases. It is well known in the industry that heads gradually accumulate e organic products which lead to stiction seizures after the heads have landed on the disks.

Actuator pivot bearings were lubricated by the test greases. Three grease types were tested: 1) mineral oil with a polyurea thickener, 2) polyolester oil with a polyurea thickener, and 3) perfluorinated polyether oil with a polytetrafluorethelyne thickener.

Airborne particle count tests were performed on five files each to assess the grease effect on disk drive contamination levels. Particle counts for sizes 0.2, 0.5 and 1.0 micron were taken from accessing files. Differences in the generation rate of aerosolized grease were measured when the files were new and also after having been exercised 10, 20 and 60 million seeks. Cascade impaction of disk drive’s air stream was analyzed by time of flight secondary ion mass spectroscopy to confirm that the aerosol particles captured were from the grease.

Files built with the perfluorinated polyether oil based grease had the lowest particle count. Files built with bearings lubricated by the mineral oil based grease had a moderate particle count. Files containing the polyol ester oil based grease had the highest particle count.
Pivot Friction Compensation Using an Accelerometer and a Disturbance Observer for Hard Disk Drives
Authors: Ishikawa Jun , Tomizuka Masayoshi
Published: March 2022

This paper considers a pivot friction compensator using the combination of an accelerometer and a disturbance observer. Noting that the pivot friction torque is approximately the difference between the scaled voice coil motor (VCM) current and the scaled carriage angular acceleration, a disturbance observer to estimate the pivot friction torque can be constructed using the above two signals. By feeding back the friction estimate into a VCM amplifier, the dynamics between the VCM current and the carriage angular acceleration are linearized to be a constant gain within an observer bandwidth. This allows the design to assume that the plant dynamics are fixed in the subsequent stage of the controller design, for example, the design of model-based controllers. The disturbance observer is designed using stochastic estimation theory. Furthermore, because the two signals are both measured continuously, the disturbance observer can be implemented experimentally as an analog system. This enlarges the observer bandwidth and the effect of the friction compensation, and reduces the reliance on the lower sampling rate of the positioning loop. To show the validity of the proposed method, experiments were conducted using a 3-1/2 inch disk drive. It has been shown that the mechanical nonlinearity, i.e., the gain reduction and the variation in the dynamics resulting from the pivot friction can be eliminated. The loop gain reduction resulting from the variation in the VCM current-to-torque constant can be recovered to be a nominal value up to 500Hz.
Effect of Suspension Nonlinearities on Rail Vehicle Bifurcation and Stability
Authors: Ahmadian Mehdi , Yang Shaopu
Published: March 2022

The effect of yaw damping nonlinearities on the hunting behavior of rail vehicles is studied, using a model for a two-axle truck (bogie) that includes the dynamics of the wheelsets and the truck frame. This study is intended to complement earlier studies by True et al. where they investigated the effect of nonlinearities stemming from creep-creep force saturation and wheel/rail contact forces. The simulation results show that yaw damping can have a mixed effect on the hunting critical speed. In some ranges, increasing damping can actually lower the critical speed, unlike the results commonly obtained from a linear model.
Heat Transfer in Laminar Channel Flow With a Non-Uniform Porous Media
Authors: Huang X. Y. , Qin W. , Liu C. Y. , Toh K. C.
Published: March 2022

This paper presents a numerical study on heat transfer by laminar flows in a two-dimensional channel. The channel is filled with a porous material which is assumed to be non-uniform across the channel, especially near the channel walls where the permeability of the porous material increases drastically to simulate the complexity at the interface between the porous media and the solid walls. Degrees of the non-uniformity of the porous material are described in this study by a parameter β. Heat sources, either constant temperature or constant heat flux, are located on the channel walls, so that heat transfer from the sources into the channel flow is greatly affected by the condition at the wall-porous media interfaces. The temperature distribution near the heat source region and the Nusselt numbers are calculated for different β values. The sensitivity of the non-uniformity of the porous media near the channel walls on the overall heat transfer is assessed. It is found that a higher non-uniformity of the porous material near the channel wall can actually enhance the heat transfer from the sources to the channel flow, as the flow velocity near the wall has been significantly increased due to the higher permeability of the porous material in the near-wall region.
An Implementation of Concurrent Engineering Concept to Injection Molding
Authors: Wang K. K.
Published: March 2022

Injection molding is known to be the most effective process for producing discrete plastic parts of complex shape to the highest precision at low cost. The concept of Concurrent Engineering (CE) is also recognized to be the way to accomplish the highest performance in a manufacturing enterprise. This paper presents a proposed plan to implement the CE concept to injection molding. IMS (Integrated Molding System) is a new initiative launched at CIMP (Cornell Injection Molding Program) to achieve this goal. The paper reviews the state-of-the-art in all three major functional components in injection molding, i.e. part design, mold design and manufacturing, and process control. Some preliminary results in optimization are presented and discussed in the paper.
Synthesis and Analysis of Quality Control Methods for Intelligent Processing of Polymeric Materials
Authors: Kazmer David O. , Petrova Tatiana
Published: March 2022

Global manufacturers of thermoplastic molded parts increasingly require 100% quality inspection levels that are difficult to achieve. While process complexity makes it difficult to attain the desired part properties during start-up. the stochastic nature of the process causes difficulty in maintaining part quality during production. This paper formally compares several alternative quality control methods that are currently utilized for processing of polymeric materials. To identify the technical issues associated with this goal, the injection molding process is described utilizing a control systems approach. Afterwards, four different methods of quality regulation are synthesized for injection molding: open loop quality control, statistical process control, trained parameter control, and on-line quality regression. For each strategy, the level of quality observability and controllability are determined against the dynamics of the manufacturing system.

The results indicate that none of the quality regulation strategies have the underlying design architecture to deliver 100% quality assurance across a diverse set of application characteristics (quality requirements, material properties, mold geometries, and machine dynamics). As such, subsequent discussion focuses on defining the system requirements for achieving ‘intelligent’ processing of polymeric materials that are needed by industry.
Finite Element Prediction of Sink Marks in Injection Molded Plastic Parts
Authors: Battey David J. , Gupta Mahesh
Published: March 2022

A numerical procedure to simulate the formation of a sink mark near the base of a rib in an injection molded plastic part has been presented. Two commercially available software packages, C-Mold and Abaqus, have been used to predict sink marks. Dependence of sink mark depth on various geometric and molding parameters has been analyzed. The predicted sink mark depth is found to be in good agreement with experimental results from the literature.
3-D Numerical Simulation of Blow Moulding Technology Involving Sequential Coextrusion
Authors: Debbaut Benoît
Published: March 2022

A 3-D numerical simulation is presented for typical applications in blow moulding involving sequential coextrusion. This technology is applied for the production of automotive boots and opaque containers or bottles with a window stripe. A fluid membrane element is developed and presented for the blow moulding simulation of geometrically complex objects. A Lagrangian formulation is used for the motion governing equations. The numerical tool is applied for predicting the material behaviour in the production of an automotive boot and of a soap bottle with a window stripe. The contact between parison and mould is handled by a robust algorithm. Next to the description of the parison deformation, we concentrate on the prediction of wall thickness, both axial and circumferential extension components and the area stretch ratio as well.
Automating the Design Process and Powder Processing of Functionally Gradient Materials
Authors: Kwon Patrick , Crimp Melissa , Chung Moon Jung
Published: March 2022

There is great deal of interest in Functionally Gradient Materials (FGMs) as evidenced by three recent international conferences on the subject (Yamanouchi, et al., 1990, Holt, et al., 1993 and Ishner and Cherradi, 1994). Similar to composites, FGMs are microscopically inhomogeneous. However, unlike most composites, macroscopic inhomogeneities are designed into FGMs. This is achieved by continuously varying the volume fraction of the second phase in a controlled manner. Thus, the distribution of the second phase has ‘to be designed’ based on the type of application and geometry of the structure. In addition, their inhomogeneous nature causes non-uniform shrinkage and cracks during processing before FGMs are ever put into service. Accordingly, two independent research programs are in progress on FGMs at Michigan State University; (1) fabrication technology and (2) design process management tools. On the former program, powder fabrication protocols are being developed to reduce processing-induced residual stresses. On the latter program, in a benchmark study for the framework developed by Baldwin and Chung (1995), the complete design process for axisymmetric FGMs cylinders is implemented.
A Damage Mechanics Based Approach to Durability Assessment of Composite Materials
Authors: Talreja Ramesh
Published: March 2022

The conventional way of durability assessment, based on experience with metals and still common in industry, is by fatigue life (S-N) curves, strength degradation curves, creep curves, etc., all of which are empirical and require extensive testing in every case. For composite materials, the cost associated with this approach is high because of the numerous parameters of consituent properties, geometry and architecture involved. Alternative approach is to characterize and analyze damage and its evolution, all of which belong to the field of damage mechanics. This paper will review this approach and the progress made to date, and project what lies ahead.
Ceramic Composites Technology Development for Industrial Applications at Babcock & Wilcox
Authors: Goettler Richard W. , Keeley Joseph T. , Wagner Richard A.
Published: March 2022

Babcock & Wilcox (B&W) and its parent corporation, McDermott International, Inc., comprise one of the world’s largest energy engineering and service companies. Included within the spectrum of it’s businesses are:

• fossil power generation systems, related environmental equipment and boiler cleaning products

• design engineering, structure fabrication, and equipment for offshore oil and gas production

• nuclear fuel and other nuclear propulsion components for the US Navy

• industrial heat exchangers and condensers

• automated work cells for material processing and inspection

• design of onshore hydrocarbon processing facilities

• environmental remediation services
Process Zone of Polycrystalline Alumina
Authors: Tran D. K. , Kobayashi A. S. , White K. W.
Published: March 2022

A number of papers, which were published during the past fifteen years, have attributed the small KIC in ceramics to the frontal and trailing fracture process zones (FPZ) associated with the crack tip. The toughness due to these two FPZ’s have been refereed to as the intrinsic and extrinsic toughness, respectively (Ritchie, 1997). Theoretical papers on the frontal FPZ considered only the crack tip shielding effect by the microvoids and did not estimate the dissipated energy by the generation and coalescence of these microvoids. Also earlier theoretical and experimental papers on the trailing FPZ considered only the crack bridging effect due to the fiber in a ceramic composite and its influence on the fracture toughness with the exception of Guo et. al. (1997) who used a hybrid experimental-numerical technique to estimate the dissipated energy in an alumina double cantilever beam (DCB) specimen. The objective of this paper is to present further results on the extrinsic fracture energy dissipated in a high density polycrystalline alumina.
Damage in Ceramic Matrix Composites With Arbitrary Microstructures
Authors: Bulsara V. N. , Talreja R. , Qu J.
Published: March 2022

It has been well-recognized that the fiber spatial distribution in a continuous fiber-reinforced (CFR) composite has a significant effect on the transverse behavior of the composite. In this study, quantitative microscopy in conjunction with finite element analysis are used to study the effects of fiber distribution on damage initiation in a unidirectional composite under a uniaxial loading transverse to the fibers.
Prediction of First Ply Failure in Scaled Cross-Ply Composite Laminates
Authors: Jackson Karen E.
Published: March 2022

Previous research on scaling effects in composite materials has demonstrated that the stress levels at first ply failure and ultimate failure of composite laminates are dependent on the size of the laminate. In particular, the thickness dimension has been shown to be the most influential parameter in strength scaling of composite coupons loaded in tension. Geometrically and constitutively scaled laminates exhibit decreasing strength with increasing specimen size, and the magnitude of the strength-size effect is a function of both material properties and laminate stacking sequence. Some of the commonly used failure criteria for composite materials such as maximum stress, maximum strain, and tensor polynomial (e.g., Tsai-Wu) cannot account for the strength-size effect In this paper, three concepts are developed and evaluated for incorporating size dependency into failure criteria for composite materials. An experimental program of limited scope was performed to determine the first ply failure stress in scaled cross-ply laminates loaded in tension. Test specimens were fabricated from AS4/3502 graphite-epoxy composite material with laminate stacking sequences of [0°n/90°n/0°n]T where n = 1–6. Two experimental techniques were used to determine first ply failure, defined as a transverse matrix crack in the 90° ply: (1) step loading with dye penetrant x-ray of the specimen at each load interval, and (2) acoustic emission. The best correlation between first ply failure analysis and experimental data was obtained using a modified Weibull approach which incorporated the residual thermal stress and the outer ply constraint, as well as the ply thickness effect A second set of experiments was performed to determine the tensile response and ultimate failure of the scaled cross-ply laminates. The results of these experiments indicated no influence of specimen size on tensile response or ultimate strength.
Measurement of Single Burning Coal Particles in Swirl-Stabilised Flames
Authors: Prassas Ilias , Taylor A. M. K. P. , Whitelaw J. H.
Published: March 2022

We report on the application of a combined shadow Doppler velocimeter and two-colour pyrometer instrument to make simultaneous measurements of the velocity, size and temperature of single coal particles in the near-burner region of 10 kW swirl-stabilised, natural-gas supported pulverised-coal flames with gas equivalence ratio of 0.69. Shadow Doppler velocimetry is an imaging technique for the simultaneous measurement of the velocity and the area of the projected image of an irregular particle illuminated by the laser beams of a conventional laser Doppler velocimeter (LDV), whilst the two-colour pyrometer was operating at wavelengths in the visible range, namely at 514.5 and 632.8 nm. Profiles of the fraction of burning particles and distributions of the size and velocity of the burning particles and the ensemble, which consisted of both burning and non-burning particles, were constructed from the raw data. In addition, an amplitude-based discrimination criterion was applied to the pyrometer measurements to produce temperature distributions of those measurements which corresponded to burning char as opposed to those corresponding to volatile flames surrounding particles. Increase of the swirl number from S = 0.41 to S = 0.57 resulted in penetration by the primary air jet of the recirculation zone on the centreline, 50% lower gas temperatures compared with S = 0.41 and accordingly, less than 5% burning particles for S = 0.57 in contrast to the 85% for S = 0.41 at the same location. For S = 0.41, except from locations near the centreline, where only particles with reverse velocities and size smaller than 60 μm were burning, only minor differences were found in the size-, velocity - distributions between burning particles and the ensemble. Despite the higher particle temperatures on the centreline, the relatively high particle burning fraction close to the oxygen-rich shear layer implies that those particles are more likely to yield NOx emissions from fuel-bound nitrogen.
Study on a Thermal Boundary Layer of Drag Reducing Surfactant Solution: Measurements of Temperature Fluctuation
Authors: Kawaguchi Y. , Daisaka H. , Li P. W. , Yabe A. , Hishida K. , Maeda M.
Published: March 2022

In order to clarify the mechanism of turbulent heat transfer in drag reducing flow by surfactant additives, temperature in thermal boundary layer in two dimensional channel has been experimentally investigated. Time mean temperature and temperature fluctuation were examined at the Reynolds number of 1.2 × 104 using a tine wire thermocouple probe. The surfactant system tested was CTAC/NaSal/water.

A high diffusivity layer near the wall was found in the thermal boundary layer of surfactant solution. The layer is formed by micellar phase change. Time scales of the temperature fluctuation in surfactant solution flow became large compared to the water flow. It suggests the role of the fluid elasticity to suppress the coherent structure near the wall. As the drag reducing additives have a direct effect on the flow structure in the buffer layer at 10 < y+ < 100, reductions of drag and heat transfer are not recovered nevertheless of high diffusivity layer.
Nonisothermal Multiphase Subsurface Transport on Parallel Computers
Authors: Martinez M. J. , Hopkins P. L. , Shadid J. N.
Published: March 2022

We present a numerical method for nonisothermal, multiphase subsurface transport in heterogeneous porous media. The mathematical model considers nonisothermal two-phase (liquid/gas) flow, including capillary pressure effects, binary diffusion in the gas phase, conductive, latent, and sensible heat transport. The Galerkin finite element method is used for spatial discretization, and temporal integration is accomplished via a predictor/corrector scheme. Message-passing and domain decomposition techniques are used for implementing a scalable algorithm for distributed memory parallel computers. An illustrative application is shown to demonstrate capabilities and performance.
An Exercise in Parallelizing a Legacy Code
Authors: Freitas Christopher J.
Published: March 2022

Parallel computing methods were used to transform a serial computer code to take advantage of the computational power of clusters of workstations and multiprocessor computers. The goal of this effort was to increase the computational speed of an existing or legacy code such that multiple simulations could be performed in a day, rather than requiring days to complete a single simulation. Further, this improvement in computational performance was to be completed quickly; i.e., in a few weeks, and was to maintain solution accuracy as established by simulation benchmarks performed with the original code. The approach taken to achieve this goal is likely typical of what others working in industrial environments may be required to do when attempting to address the issue of transitioning from serial computing environments to one based on a parallel architecture. The essential elements to recasting a serial code into a parallel code are discussed.
Design Considerations in Avionics Electronic Packaging
Authors: Jamnia Ali , Walter Robert E.
Published: March 2022

In designing avionics electronics packages, four areas of engineering need to come together and work concurrently as a team. These are electronic, electro-mechanical packaging, thermal and finally vibration engineers. Often times, thermal and vibration analyses are done only as an afterthought through experimental means to ensure Federal Aviation Authority (FAA) Federal Aeronautics Regulations (FAR) and / or ARINC standards.

In this paper, the mechanics and thermal design procedure and calculations (based on both analytical means and finite element methods) of an airborne ARINC 746 Cabin Telecommunications Unit (CTU) are discussed along with the relevant FAR’s, as well as, ARINC standards are considered. Finally, reliability and failure rates of components and their effects on the performance of the system are studied.
Manufacturability of Underfill Processing for Low Cost Flip Chip
Authors: Baldwin Daniel F. , Pascarella Nathan W.
Published: March 2022

Advanced electronics assembly based on direct attachment of semiconductor devices to printed circuit boards is a rapidly growing technology. Direct chip attach (DCA) or flip chip on board (FCOB) processing typically requires application of underfill materials in order to achieve adequate reliability for commercial electronic applications. Unfortunately, flip chip on board processing has yet to become a low cost, high throughput process compatible with high volume surface mount processing. In order for FCOB processing to be SMT compatible, innovative techniques for underfill processing are required. This paper analyzes underfill processing in order to assess manufacturablity in terms of productivity and cost. In particular, four techniques for underfill processing are analyzed including capillary flow, vacuum assisted capillary flow, injection flow, and compression flow processing.
Moisture Diffusion in Epoxy Molding Compounds Filled With Silica Particles
Authors: Uschitsky M. , Suhir E.
Published: March 2022

Mechanical reliability of epoxy molding compounds in plastic packages of integrated circuits (IC) devices is affected to a great extent by the materials ability to absorb moisture. Accordingly, the objective of the study is to evaluate the effect of moisture sorption on the mechanical properties of the compounds. The diffusion of water in compounds filled with silica and alumina nitride particles has been studied experimentally for systems with moderate and high concentration of fillers. The analysis of the weight gain profiles has shown that the process of moisture diffusion is non-Fickian and that the moisture weight gain depends on the specimen’s relative humidity and the concentration of fillers. As to the hygro-thermal (swelling) stress, caused by moisture diffusion, we found that this stress is very low (its average value does not exceed 662 psi). We showed also that moisture diffusion leads to an appreciable decrease in the compound’s strength and to a substantial increase in the material’s plasticity. The obtained results can be helpful in the analysis of the mechanical behavior of epoxy molding compounds used in electronic packaging.
Thermoelastic Behavior of Filled Molding Compounds: Composite Mechanics Approach
Authors: Uschitsky M. , Suhir E. , Kammlott G. W.
Published: March 2022

Reliability of epoxy molding compounds used in plastic packages of integrated circuit (IC) devices depends on the level of thermal stresses caused by the thermal expansion (contraction) mismatch of the epoxy and the silicon materials. In this analysis we asses the effect of silica fillers on the thermal stresses. We conclude that thermal stresses in the epoxy molding compound (composite) can be indeed reduced by the application of appropriate fillers. We found, however, that the volume concentration of the fillers, does not have to be larger than 0.3 to keep the thermal stresses at a sufficiently low level. This number is close to the fillers volume concentration (c = 0.336–0.390) in actual commercially available molding compounds. The obtained results and recommendations can be helpful in the analysis of stresses and physical design of plastic packages of IC devices.
Numerical Computation of the Heat Transfer to a Spherical-Tip Anode During an Electronic Flame Off Process
Authors: Sripada Srinivas S. , Ayyaswamy P. S. , Cohen I. M.
Published: March 2022

In the ball-wedge bonding process employed in microelectronic packaging, the first step is the formation of a spherical tip by the melting and roll-up of a segment of a cylindrical wire. The heat transfer for the melting and roll-up to a spherical-tip shape is provided by a plasma are that is struck between the wire tip (anode) and a flat plate cathode (wand). Eventually, the spherical tip becomes part of a ball. The ball so formed is bonded on the bond pad of a chip, and the unmelted segment of the wire is looped to form a second (wedge) bond on the lead frame. This provides the interconnection between the chip and the external world. The plasma arc provides heat energy to the wire causing it to melt. A portion of the energy generated by the arc is lost by conduction up the wire, while another portion is lost to the surroundings by radiation and convection. A portion is also lost to the cathode plate. In order to estimate the various heat transport quantities, a numerical simulation of the plasma arc process is required. Here, we provide results of such a numerical simulation. A set of continuum conservation equations for the charged particle densities and the temperatures in the discharge gap are solved, along with Poisson’s equation for the self-consistent electric potential. The equipotential contours, the electron number density and temperature variation in the discharge gap, and the results for the heat transfer to the spherical tip of the wire are presented. Once the heat transfer is evaluated in this manner, subsequent calculations for melting and the ultimate shape and size of the ball may be made. These calculations in turn may be used to develop optimal characteristics for bonding which consist of near-spherical balls with minimal porosity. These are known to be the best candidates for a secure interconnection between the chip and the lead-frame. Although in the past we have published many results for related situations, this is the first time when the anode geometry is completely taken into account. The numerical calculations involve adaptive grid generation based on a body-fitted coordinate system. Results provided here are of immediate application value to the microelectronic packaging industry.