bluuebunny/crossref_metadata_2025_split huggingface dataset:
Axisymmetrical Thermal Stress Analysis of Laminated Composite Finite Hollow Cylinders Restricted at Both Ends in Steady State
Authors: Katsuo Masahide , Sawa Toshiyuki , Kawaguchi Koji , Kawamura Hiroshi 
Published: July 2023

Abstract
The thermal stress distributions of laminated composite finite hollow cylinders restricted at both ends and at one end of the cylinders are analyzed using the thermoelastic displacement potential and Michell’s stress functions based on the axisymmetrical theory of elasticity. In the numerical calculations, the thermal stress distributions in the laminated composite finite hollow cylinders are examined. The effects of restrictions at the end of the cylinders on the thermal stress distributions are clarified. The analytical results are compared with the results obtained from the plain strain the ory. It can be seen that the differences in the stresses between the inner cylinder and the outer cylinder increase near the restricted end. The hoop and the axial stresses distribute discontinuously at the interface of the cylinders. The difference in the hoop stress at the interface is minimal in the case of the plain strain theory. For verification, the strains were measured and the analytical results were in fairly good agreement with the experimental results.
Systems Engineering: A New Framework for Engineering Design
Authors: Hazelrigg George A. 
Published: July 2023

Abstract
There is a widespread tendency to frame engineering design as a problem-solving activity. In this framework, the goal of a design is to satisfy functional requirements, subject to constraints, at minimum cost. It is shown below that this approach can lead to seriously non-optimal designs, and it further denies the use of a broad spectrum of fruitful tools that open up to the design engineer if only design is viewed instead as a decision-making process. In this context, a definition is given for systems engineering. Then, this definition is built upon to create a new framework for engineering design that has at its base the assertion that design is a process of decision making that is amenable to treatment using classical decision theory.
A Thermal Fatigue Model for Surface Mount Leadless Chip Resistor (LCR) Solder Joints
Authors: Pao Y.-H. , Jih E. , Siddapureddy V. , Song X. , Liu R. , McMillan R. , Hu J. M. 
Published: July 2023

Abstract
The reliability of surface mount leadless solder joints, e.g., LCCC (leadless ceramic chip carrier), LCR (leadless chip resistor), and LCC (leadless chip capacitor), has been a long-term research topic due to the concern of thermal fatigue failure resulting from significant stresses and strains induced in the joint. Numerous studies of failure analysis of leadless solder joints exist in the literature, and a number of life prediction models based on different failure characterizing parameters, e.g., total strain, plastic strain, strain energy density, etc., have been developed for particular loading conditions, such as isothermal or thermal cyclic fatigue tests. To name a few, e.g., one can refer to Engelmaier (1984), Cltterbaugh and Charles (1985), Hall and Sherry (1986), Clech and Augis (1987), Wong et al. (1988), Bae et al. (1989), Solomon (1990), Frear et al. (1991), Satoh et al. (1991), Lee and Stone 91991), Lau (1991), Govila et al. (1994), Schroeder and Mitchell (1994), JPL (1994), Syed (1995), Wen and Ross (1995), Jih and Pao (1995), Zhang et al. (1996), Kawai et al. (1996), Hu (1996), Guo and Conrad (1996), Lin et al. (1996), and Lau and Pao (1996).
Flow Modeling of Wire Sweep in Transfer Molding
Authors: Chen Xiao Hong , Lee K. S. , Yuen M. M. F. , Tong Pin 
Published: July 2023

Abstract
Transfer molding is one of the most widely used process for encapsulating integrated circuits. Wire sweep is becoming a critical process defect in the era of miniaturization of electronic products. This is because wire sweep can cause electrical short as integrated circuit lead count increases which leads to reducing wire pitches. Common practices in predicting wire sweeps in encapsulation calculate first the flow in the cavity without wires. The drag force on the wires is then calculated based on the local velocity using the flow drag relationship of flow in an infinite medium. Recent experimental result has shown that wire density had a strong influence on wire sweep. This paper describes both an empirical prediction and a stokes flow analysis of flow wire interaction on wire sweep. The analysis determined the flow induced loads on the wires for different wire shapes, spacing, and locations from the wall.
Computer Modeling of Steady and Transient Flows Within a Gasoline Fuel Injector
Authors: Ren Wei-Min , Nally John F. 
Published: July 2023

Abstract
The steady and transient internal flows within an automotive fuel injector are studied by solving ensemble-averaged, three-dimensional mass and momentum conservation equations. In the analysis, the effects of operating pressure, orifice size, and needle lift on the static flow rate, and the effect of opening rate on the dynamic flow rate have been parametricly investigated. Pressure drop was varied from 100 kPa to 500 kPa; the orifice diameter and needle lift ranged between 400 μm to 700 μm and 60 μm to 120 μm, respectively. A multiblock moving mesh method was used to simulate the needle motion.
Predicted static flow rates provide good agreements with the experimental measurements. Static flow increases as the orifice diameter increases. For a constant orifice diameter, static flow rate is found sensitive to the changes of the needle lift for a large nozzle while relatively insensitive for the smaller one. Dynamic flows under various needle opening rates are calculated and results are presented.
The LVEL Turbulence Model for Conjugate Heat Transfer at Low Reynolds Numbers
Authors: Agonafer Dereje , Gan-Li Liao , Spalding D. Brian 
Published: July 2023

Abstract
A simple method is described for calculating distances from walls in circumstances of complex geometry. This is then used as the basis of a comparative study of conjugate heat transfer, involving two previously published and one new low-Reynolds-number turbulence models. It is argued that the new model, called LVEL, performs as well as the older Lam-Bremhorst-Yap and Two-Layer-κ-ε models. Since it is computationally less expensive, and easily applied to three-dimensional problems, it is recommended for practical use, especially for electronics-cooling applications.
The Determination and Utilization of AuSn Solder Creep Properties to Bond GaAs Dice to Diamond Substrates
Authors: Chandran B. , Schmidt W. F. , Gordon M. H. , Djkaria R. 
Published: July 2023

Abstract
The stress in gallium arsenide dice larger than 2mm × 2mm conventionally bonded to diamond substrates using eutectic gold-tin solder is larger than the dice’s fracture strength leading to fracture during bonding. This paper discusses a novel bonding technique to reliably bond large gallium arsenide devices to diamond substrates using eutectic gold tin solder. In this technique, the cooling process after bonding is controlled to induce creep in the solder layer. Creep deformation in the solder layer relieves part of the stress in the die and thereby prevents die cracking. An analytical model describing the stress relaxation in the die due to solder creep deformation was developed. Due to the lack of published creep properties of AuSn solder, they were experimentally determined. Optimal cooling curves were generated using the relaxation model to reliably bond different sizes and thicknesses of GaAs dice to diamond substrates. Bonding experiments indicate that all the bonded dice cooled using conventional techniques cracked after bonding and that those cooled using the generated cooling schemes survived. Previously, these creep properties were boot-strapped from the published values for other solders. The experimentally obtained properties deviate substantially from those previously boot-strapped. However, it is interesting to note that the implied cooling schemes were similar.
Design of Experiment Based Evaluation of the Thermal Performance of a Flipchip Electronic Assembly
Authors: Mithal Pankaj 
Published: July 2023

Abstract
A finite element method based design of experiment (DOE) study was conducted to evaluate the thermal performance of an automotive electronic assembly. The assembly design consists of a flipchip IC mounted on a thin FR-4 PCB bonded to an aluminum backplate. The study captures the influence of the number of thermal vias present in the substrate, the thermal conductivity and thickness of the epoxy layer between the substrate and the backplate, the IC active area, thermal conductivity of the underfill marterial and the power dissipation of the IC, on the thermal performance of the assembly. Single factor analysis of various design parameters indicates that the thermal conductivity and thickness of the epoxy layer are the most critical parameters of the design from a thermal performance viewpoint.
DYNA3D Simulations of Pendulum Impact Tests on Steel Guardrails
Authors: Bank Lawrence C. , Gentry T. Russell , Yin Jiansheng , Lamtenzan J. Daniel 
Published: July 2023

Abstract
The response of a G4(1S) strong post steel w-beam guardrail system to dynamic impact has been investigated in a series of full-size physical tests and in simulated experiments using LLNL-DYNA3D. The physical tests were conducted at the Federal Outdoor Impact Laboratory (FOIL) at the Turner Fairbank Highway Research Center of the Federal Highway Administration (FHWA) in McLean, Virginia using a pendulum. In the pendulum tests, an 880 kg mass was used to strike the rail perpendicular to its face. The rail section was attached to steel posts and blockouts and supported in a specially designed fixture. Initial velocities of the pendulum at impact were 9.25, 20, 30 and 35 km/h. From acceleration data taken during the testing, acceleration, force, velocity and displacement histories of the impact event were calculated. Data from the LLNL-DYNA3D simulations of the impact tests compared well with the data obtained from the full-scale testing. Animations of the deformed shapes of the rails at 25 msec intervals compared favorably with high speed film images. Force versus displacement histories showed good agreement with those obtained from quasi-static experiments.
Study of CVD Coated and Uncoated INCO 718 Exposed to Particulate Flow
Authors: Shanov Vesselin , Tabakoff Widen , Gunaraj J. A. 
Published: July 2023

Abstract
The major problem confronting developers of coal burning boilers, fluidized beds, and gas and steam turbines, is the serious erosion of the systems’ components by the suspension of fly ash or other solid particles in the flow. A permanent loss of performance is associated with surface erosion, which is caused by particle surface impacts. To improve the resistance of hot erosion and corrosion, new alloys and coatings are investigated. The objective of this research work is to investigate the basic erosion process and fluid mechanics associated with material degradation in coated and uncoated INCO 718. This nickel-based superalloy is frequently used for manufacturing of jet engine and rocket components. Chemical vapor deposition (CVD) technique is used to apply a ceramic coating (TiC) to the INCO 718 superalloy. The erosive wear of the samples is investigated experimentally by exposing them to chromite particle laden flow at velocities from 180 to 305 m/s and temperatures from ambient to 538°C in a specially designed erosion wind tunnel. In addition, the eroded surface is examined by scanning electron microscopy (SEM). The obtained results show the effect of the impingement angle, temperature and velocity on the erosion rate. The cumulative effects of the impacting particles mass on the weight loss and the erosion rate of the coating are also investigated. This study demonstrates that the tested CVD titanium carbide is a perfect high temperature erosion resistant coating for INCO 718.
Dynamic Response and Fatigue Characterization of Aluminum Boron Carbide Ceramic Composite Materials for Disk Drive Actuator Applications
Authors: Perettie D. J. , Fox R. T. , Pyzik A. J. , Han C. , Macioce P. , Nashif A. 
Published: July 2023

Abstract
Use of alternate materials has been suggested as a means of achieving improvements in disk drive performance, with actuator support components representing one area where such a change could prove beneficial. Increases in specific stiffness along the head support structure/assembly serve to increase the frequencies at which resonance is observed, ultimately translating to a potential reduction in off-track error due to the onset of uncontrolled vibration observed at the head-disk interface. Additional benefits projected to be attributable to these structural stiffness influences include improvement of both access times and usable areal density. Aluminum-Boron Carbide ceramic composites possess favorable material property combinations which readily lend themselves to this application. Components fabricated to designs developed for this purpose were tested for dynamic response when subjected to both cyclic temperature exposure (−40°C to 100°C) and controlled humidity (85% at 85°C) conditions. These results, combined with cyclic fatigue characterization suggest that Aluminum-Boron Carbide can function as a feasible, higher performance alternative to the conventional stainless steel, aluminum, and magnesium metals currently used for this purpose.
Suture-Induced Intramural Stresses and Intimal Hyperplasia
Authors: Ballyk Peter D. , Ojha Matadial , Walsh Colin , Butany Jagdish 
Published: July 2023

Abstract
Intimal hyperplasia is a major cause of outflow stenosis and thrombosis of prosthetic bypass grafts. In an end-to-side graft-artery anastomosis, the thickness of the early cellular lesion is greatest at the suture-line, where the distribution is roughly uniform around the junction (Bassiouny et al., 1992; Trubel et al., 1994). This distribution is difficult to explain on the basis of either hemodynamic or compliance mismatch factors alone since these effects are not uniformly distributed (Ojha, 1994; Ballyk et al., 1995).
Computational Simulation of Magnetic Resonance Angiograms in Stenotic Vessels: Effect of Stenosis Severity
Authors: Bergman Harris L. , Siegel John M. , Oshinski John N. , Pettigrew Roderic I. , Ku David N. 
Published: July 2023

Abstract
Post stenotic signal loss limits the widespread use of magnetic resonance (MR) angiography. The signal loss causes ambiguity when determining the degree of stenosis and when assessing patency. Thus it is important to devise strategies for reducing signal loss associated with stenoses.
Modeling Contact in Biological Joints Using Penalty and Augmented Lagrangian Methods
Authors: Weiss Jeffrey A. , Schauer Dale A. , Gardiner John C. 
Published: July 2023

Abstract
Contact is inherent in biological joints. Examples include contact between articulating surfaces of joints and between soft tissues and bone. To accurately simulate the mechanics of joints using the finite element method, a robust treatment of contact is essential. The objective of this study was to compare the performance of standard penalty methods to the augmented Lagrangian (AL) method for enforcing contact in a model of joint mechanics, using both computational cost and accuracy for the comparisons. Comparisons were carried out using a representative problem from finite element simulations of joint mechanics.
The Effect of Strain Rate on the Axial Stress-Strain Response of the Human Annulus Fibrosus in Tension and Compression: Experiment and Poroelastic Finite Element Predictions
Authors: Duncan Neil A. , Ashford Frank A. , Lotz Jeffrey C. 
Published: July 2023

Abstract
We investigated the effect of strain rate on the axial tension and compression response of the annulus fibrosus. In compression, the stress-strain response of the annulus stiffened by 800% when loaded at physiologic loading rates compared to quasi-static rates, whereas in tension the annulus stiffened by only 100%. We also developed a nonlinear poroelastic FEM to predict the axial tension and compression response of the annulus. The model was unable to predict the significant effect of strain rate on the axial stress-strain response we observed experimentally, though excellant agreemant was found at quasi-static strain rates.
Wall Shear Stress Gradient Measurements Within the Distal Anastomosis of Vascular Bypass Grafts: An In Vivo Model Study
Authors: Keynton Robert S. , Evancho Mary M. , Sims Rick L. , Rodway Nancy V. , Li Qun , Mallugari Nagesh , Rittgers Stanley E. 
Published: July 2023

Abstract
There has long been a debate in the bioengineering community as to the role of hemodynamics in the development of cardiovascular diseases. Several researchers [1,2] have hypothesized that the Wall Shear Stress Gradient (WSSG) is directly related to the development of intimal hyperplasia [IH] within vascular bypass grafts. Unfortunately, this hypothesis is based on results from numerical [1,2] studies and not direct in vivo measurements. Therefore, it is the purpose of this paper to determine the relationship between the wall shear stress gradient and the development of IH at the distal anastomosis of vascular bypass grafts in an in vivo model.
Infrared Photodetection in the Picowatt Range Using Uncooled Micromechanical Sensors
Authors: Lai J. , Perazzo T. , Shi Z. , Majumdar A. 
Published: July 2023

Abstract
Bi-material microcantilever beams have been used to photothermally detect infrared and visible radiation with 10 pW resolution for power and 3 fJ for energy, while operating at room temperature. The resolution was improved by an order of magnitude by optimizing the thickness ratio of the two beam materials, as well as by modulating the input radiation at sufficiently high frequency to be in the thermal white-noise limit of the cantilever. Noise-equivalent radiative power was detected with a noise-spectral density of 100 pW/Hz and a detectivity, D*, higher than 108cmHz/W.
Optimal Design of a Microfabricated Diffusion-Based Extraction Device
Authors: Holl Mark R. , Galambos Paul , Forster Fred K. , Brody James P. , Yager Paul 
Published: July 2023

Abstract
The miniaturization of micro-fluidic chemical assays of fluid mixtures containing particles such as biological molecules and cells is a technically and commercially significant objective. Successful automation of chemical analysis of small samples requires seamless integration of several subsystems that perform tasks routinely carried out by a skilled technician. In this paper is presented a methodology for the optimal design of a novel micro-flow diffusion-based constituent extraction device based on parallel fluid flow through a microchannel. The streamwise distance required for the constituent being extracted to achieve an average concentration across the micro-channel that is a fixed percentage of the equilibrium concentration is defined as the equilibration length. The constituent concentration within the micro-channel is calculated using a 1-D analytical diffusion model. The equilibration length is used to construct a family of process space design curves specific to the extracted constituent. An optimization objective function is specified to identify the design that maximizes the volume flow rate of product stream.
The methodology is applied to the design of a device for the extraction of albumin (a protein present in blood) from a carrier sample stream with viscosity approximately that of water. The device is specified for a length sufficient for the mean albumin concentration in the product stream to reach a value that is 99% of the equilibrium concentration of albumin for an infinite length device. This process sensitivity information provides design requirements for upstream and downstream fluidic components, and is essential for integration of the device into a “lab on a chip” chemical analysis system.
A Bimetallic Thermally Actuated Micropump
Authors: Yang Yue , Zhou Zhaoying , Ye Xiongying , Jiang Xiaoning 
Published: July 2023

Abstract
In this paper a bimetallic thermally-actuated membrane micropump is presented. The micropump have been fabricated using silicon micromachining technique. The pump consists of two chips and comprises a pump chamber, two bimetallic actuators and two check valves integrated on the same structure. The size of the pump chamber is about 3mm × 3mm × 0.7mm, and that of microvalve outlet is 100 μm × 100 μm. Flow characteristics of the pump and its main components are tested and discussed. The maximum flow rate of the pump is approximately 43 μl/min, under the driving voltage of 16V and frequency of 0.9 Hz.
Dynamic Fracture via Molecular Dynamics and Cohesive Finite Element Method
Authors: Xu X.-P. 
Published: July 2023

Abstract
Dynamic fracture is investigated using molecular dynamics and cohesive finite element approaches. The molecular dynamics technique is based on the motion of a given number of atoms governed by their mutual interatomic interactions that are described by interatomic potentials. Using million atom systems, many recent laboratory findings occur in our simulation experiments. With every atomistic degree of freedom being accounted for, microscopic processes are identified. The continuum formulation involves specifying a set of cohesive surfaces. Each cohesive surface is described by a traction-displacement relation that allows for the creation of new free surface. The solid under consideration has inhomogeneities randomly distributed. Results for crack growth and branching are in accord with experimental observations. Some discussion on coupling continuum finite element and molecular dynamics is also presented.