bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of Failure Evolution in 3D Cellular Woven Composite Systems
Authors: Baucom Jared N. , Zikry Mohammed A. , Qiu Yiping 
Published: November 2021

Abstract
This investigation examines the role of porosity in the perforation resistance of 3-D woven fiber reinforced epoxy panels under impact by rigid projectiles at velocities of 100 to 200 m/s. Incident and residual velocities are measured to determine the energy absorption by the target. To compare samples of different areal density, the energy is normalized by the target areal density. The sample responses segregate by porosity, and the more highly porous samples absorb a greater amount of specific energy. The reason for this is unclear but may be due to the deflection of matrix cracks by pores or due to the greater flexibility of the fibers to absorb energy through tensile straining. Although porosity is generally an undesirable property in textile composites, the induction of porosity may result in reduced panel weight without degradation of ballistic performance, a clear advantage for weight minimization.
Crack Growth in Metal-Ceramic Composites
Authors: Agrawal Parul , Sun C. T. 
Published: November 2021

Abstract
This research focuses on the fracture mechanisms in various metal-ceramic composites. The objective was to study the effects of volume fractions, residual stresses and other microstructural features like particle size and contiguity of the constituent phases, on fracture. Neutron diffraction tests were performed to measure residual stresses in these composites. In-situ 3-point bend tests were performed inside the ESEM (Environmental scanning electron microscope) chamber to observe crack growth. It was found that residual stresses and contiguity play dominant roles in fracture and defining the crack path. The correlations between residual stresses and other microstructural features with the crack path and failure mechanisms were established based on experimental observations.
Failure of Laminated Composites at Thickness Discontinuities Under Complex Loading and Elevated Temperatures
Authors: Lee S. , Knauss W. G. 
Published: November 2021

Abstract
Failure initiation of laminated composites with discontinuous thickness has been studied in terms of typical structural load description (tension, shear force and bending moment) rather than in terms of micromechanics considerations. Four types of specimens of different stacking sequence were examined to determine failure initiation, analyzed subsequently via a finite element analysis (ABAQUS), divided into two groups that evoke cross-ply failure, on the one hand, and delamination type failure on the other. For unidirectional fiber orientation in the tension direction and across the interface, failure occurs through cracking and delamination. While the initiation strength for this failure mode is significantly higher than for cross-ply configurations, the residual strength after initiation increases only marginally (10%) beyond the initiation point. For cases involving cross-plies on either side of the interface, failure initiation occurs by matrix cracking. In these cases the residual load bearing capability was 20 to 30% higher than the corresponding failure initiation loads. The data are analyzed in terms of the Tsai-Hill criterion and in terms of an energy release criterion that has been discretized in a manner consistent with a non-singular treatment of the step “discontinuity”. Assuming that time dependent aspects of the failure process are not dominant, elevated temperatures did not change the general results of how bending and tension loads interact; however the magnitude at which the failures occur depends on the temperature, with increasing temperature leading to decreasing load tolerance.
Optimal Design of Stiffened Composite Panel for Performance and Manufacturing Considerations
Authors: Yoo J. , Hajela P. 
Published: November 2021

Abstract
This paper describes a design study in which a stiffened composite wing panel is configured for a combination of performance and manufacturing related requirements. The principal focus of the paper resides in demonstrating the adaptation of newly emergent soft-computing methods for a variety of sub-tasks that constitute the design process. These sub-tasks include function approximations, modeling of processes that lack a good analytical description, and design optimization in a space that consists of a mix of integer, discrete, and continuous design variables. Soft computing techniques discussed in this context include function approximations using back-propagation neural networks, modeling of the composite panel fabrication process using evolutionary fuzzy models, and the application of genetic algorithms and immune network modeling to the optimization problem.
Nonlinear Interaction of Ultrasonic Beams in Air
Authors: Weiguo Dong , King Lim Mong , Xiaoyang Huang 
Published: November 2021

Abstract
Parametric arrays are widely used in underwater environment. Recently, efforts have been made to apply parametric radiation to audio sound reproduction in air. However, some presumptions used in underwater acoustic analyses are not applicable in air, especially for sources with small sizes. A possible solution is to numerically solve the KZK equation, which is the well accepted “exact” model equation for directional acoustic beams. In this paper, a small plane circular piston source is considered and a finite difference technique is used to numerically solve the KZK equation. Experiments are also performed. It is shown that numerical results are in good agreement with the experimental measurements.
Boundary Conditions for a Traveling Web Detaching From a Rotating Cylinder
Authors: Reuter Christoph G. 
Published: November 2021

Abstract
High speed traveling webs appear in a number of technical applications such as plastic foil or paper production machinery and printing machines. Almost all mechanical models for the dynamic behaviour used so far, assume simple support boundary conditions. In reality, in the case of two-dimensional webs immersed in a viscous fluid, a low pressure zone will be present under the web near the point where the web detaches from the rotating drum. Other effects such as adhesion forces may also contribute. Thus, as can often also be seen already by naked-eye examination, the web does not detach tangentially from the drum.
In this paper a mechanical model for small amplitude vibrations of a traveling web with small sag is developed, which takes into account the effect of the above described upstream boundary condition. The web is modeled as a one-dimensional heavy string without bending stiffness. The assumption of quasi-static stretching is made, i.e. infinitely high wave speed is assumed for longitudinal waves.
Key Parameters Affecting Solder Joint Life of Chip Resistors and Chip Capacitors Mounted on Insulated Metal Substrate
Authors: Sangalli Nicoletta , Barker Donald B. 
Published: November 2021

Abstract
Aluminum insulated metal substrate (IMS) is often used as an alternative to FR-4 to enhance heat dissipation in high power applications. Although IMS offers better heat dissipation, the solder joint life of leadless chip resistors and chip capacitors under thermal cycling can decrease. This is due to the higher mismatch of the coefficient of thermal expansion between the ceramic based components and the aluminum board.
This paper has two main objectives. One is to investigate the sensitivity of solder joint life of ceramic chip capacitor and chip resistor mounted on IMS to variations in dielectric thickness, board material, and solder thickness on. This sensitivity analysis is conducted with finite element analysis (FEA) simulation. The other objective is to determine the solder joint life for different resistor sizes at different temperature ranges with FEA modeling and experiment data. These results are presented in terms of design guidelines to be used in the selection of component size, board material, and temperature ranges, given an expected solder joint life.
Application of a Novel Flip Chip Solder Joint Inspection System to Chips on an FR-4 Substrate
Authors: Erdahl Dathan S. , Liu Sheng , Ume I. Charles 
Published: November 2021

Abstract
Because the trend in electronic interconnection technology is toward the development of solder bump technologies, that include flip chips, chip scale packages, multi-chip modules (MCMs), and ball grid array (BGA) packages, solder bump inspection methods must be developed to allow rapid, accurate, and high resolution on-line inspection of joint quality. Although traditional methods can detect some manufacturing defects, they do not actually test the mechanical quality of the connection. A novel solder-joint inspection system has been developed based on laser ultrasound and interferometric techniques. A pulsed laser generates ultrasound on the chip’s surface and the whole chip is excited into vibration modes. An interferometer is used to measure the vibration displacement of the chip’s surface. Solder joints with different qualities cause different vibration responses, acting as constraints on the system. The system was used to inspect the quality of solder joints on a group of flip chips mounted on FR-4 substrates, and the results show the ability of the system to detect defects such as missing solder balls, cracked chips, and gross misalignment.
A Review of Electrically Conductive Adhesive Technology for Use in Surface-Mount Microelectronics
Authors: Rafanelli Anthony J. 
Published: November 2021

Abstract
Interest in alternatives to lead solders continues to increase due to several initiatives addressing the reduction of lead usage and subsequent exposure to the environment. Alternative materials can be categorized into two main groups: electrically conductive adhesives (polymers) and non-lead solders. Over the past ten years, many non-leaded solders have been developed and introduced to the electronics industry. Despite some success regarding processability, several issues still exist regarding use of these materials as “drop-in” replacements for traditional leaded solders, e.g. eutectic tin-lead. This paper provides an overview of the second alternate material group, i.e. electrically conductive adhesives. An attempt is made to compare characteristics of these materials to the tin-lead benchmark. A summary of key material properties is also included. Finally, a position is presented regarding the approaches taken in evaluating these materials as suitable substitutes for tin-lead eutectic solder. Focus is on applications in surface mount technology (SMT) interconnection since solder is the primary bonding medium for interconnection. In general, these materials are acceptable for most applications. Applications under harsh service and environmental conditions, however, would require evaluation on a case-by-case basis.
Characterization of the Performance of Flat Heat Pipes for Electronics Cooling
Authors: Vadakkan Unnikrishnan , Garimella Suresh V. , Sobhan Choondal B. 
Published: November 2021

Abstract
A computational model has been developed to analyze the transient and steady-state performance of flat heat pipes and assess their performance under different operating and geometric parameters, in order to arrive at optimal designs. The model assumes two-dimensional fields for flow and heat transfer and solves the governing differential equations using a finite-difference approach. The wick region of the heat pipe is analyzed using transport equations for a porous medium. The influence of axial heat conduction along the wall, as well as the energy transport in the wick, on the velocity and temperature distributions is examined. The overall performance of the heat pipe is quantified by calculating an effective thermal conductance from the heat input and the temperature drop along the heat pipe wall. Parametric studies are conducted using the model to investigate the dependence of the heat pipe performance on the heat input at the evaporator, the containing wall thickness, and the porosity of the wick.
Rice SPENDULAP: A Laboratory Apparatus to Illustrate Key Concepts in Kinematics, Dynamics, and Control
Authors: Dabney James B. , Ghorbel Fathi H. 
Published: November 2021

Abstract
The Rice SPENDULAP is a spherical pendulum apparatus that is useful for illustrating a variety of important topics in kinematics, dynamics, and control. This paper describes how the SPENDULAP can be used to supplement the classroom so as to enhance students’ understanding of three-dimensional kinematics and dynamics. The paper also describes the use of the SPENDULAP to illustrate key topics in nonlinear systems analysis, such as linearization and the state portrait. Finally, the use of the SPENDULAP as an example for simulation and nonlinear control is described. More information on the SPENDULAP is available at http://dacnet.rice.edu/users/ghorbel/index.html.
Aeroelastic Vehicle Sensor Placement for Feedback Control Applications Using Gain Stability
Authors: Al-Shehabi Abdul G. , Newman Brett 
Published: November 2021

Abstract
Optimal positions for aeroelastic vehicle feedback sensors, which meet design constraints and control requirements, are difficult to determine. This paper introduces a systematic and optimal approach for choosing sensor locations based on gain stability criteria. A steepest descent optimization method with constraints is used to minimize such objective criteria, which are based on the dipole magnitudes for each aeroelastic mode appearing in a traditional Evans diagram for a scalar control loop. Each dipole magnitude term is multiplied by a weight parameter. Rigid-body augmentation characteristics are implicitly accounted for in the type of input-output pairs utilized and in predefined loop compensation structure. Constraints enforcing minimum phase zeros in the transfer function are also considered. A flexible aircraft structure is used as an example to demonstrate this procedure. Results indicate flight control and structural mode control characteristics can be effectively balanced.
Fault Diagnosis of an Internal Combustion Engine With Embedded Radial Basis Function Modules
Authors: Gan Chengyu , Danai Kourosh , Rizzoni Giorgio 
Published: November 2021

Abstract
The application of a modeling compensation method is studied in fault diagnosis. This compensation method relies on embedding single-input single-output radial basis function (RBF) modules within the nonlinear model of the plant so as to provide a basis for closed-form representation of the uncertain components. The weights of these RBF modules are then adapted on-line by the extended Kalman filter (EKF), in tandem with state estimation, to provide a representation of these uncertain components within their range of variation. The improved performance of the EKF-based observer in presence of time-variability has motivated exploring its utility in fault diagnosis of an automotive engine, where its performance is studied in detection of a throttle sensor fault.
Electromagnetic Levitator at Space Power Institute, Auburn University
Authors: Ciocirlan Bogdan O. , Marghitu Dan B. , Beale David G. , Overfelt Ruel A. 
Published: November 2021

Abstract
In this paper, the electromagnetic levitation instrument designed by Space Power Institute at Auburn University is analyzed. An analytical model to compute the Lorentz force that supports the specimen against gravity is proposed. The equation of vertical motion of the specimen is developed and linearized. A fuzzy logic control system designed to stabilize the motion of levitated specimens is also presented.
Detection of Lateral Damping Friction in Surface Textures Presented via a Force Feedback Haptic Interface
Authors: Weisenberger Janet M. , Krier Michael J. , Kreidler Sandra M. 
Published: November 2021

Abstract
Previous work with real surfaces has suggested that variations in the coefficient of surface friction do not affect the judgment of surface roughness. Nonetheless, it is likely that subjects are able to detect changes in frictional characteristics even when judgments of roughness are unaffected. The goal of the present study was to determine whether users of a force-feedback haptic interface could discriminate surfaces containing a lateral viscous friction component from surfaces that did not. Three subjects were tested in an adaptive same-different task, in which they were asked to judge whether two simulated surface textures felt the “same” or “different.” On each trial, one surface contained lateral damping forces in addition to vertical point-source forces, and the other did not. Values of the damping constant for the surface containing lateral damping were adjusted to determine the threshold for discriminating a surface with a lateral damping force from a “frictionless” surface. Results suggest that users are quite able to detect a frictional component even at relatively small lateral forces. These results are considered in view of the notion that for some tasks an accurate rendering of frictional forces may improve task realism.
Algebraic Surface Derivatives for Rendering Virtual Contact Force
Authors: Nelson Donald D. , Cohen Elaine 
Published: November 2021

Abstract
Previous augmented reality displays have rendered crisp virtual walls and virtual objects with finger-surface reactions through haptics feedback devices. The widely used stiffness (or impedance) methods penalize a user’s intrusion into a virtual surface with a force response dependent on the amount of penetration along the contact normal at the virtual proxy location. We present an alternative approach for computing the surface impact response that projects Lagrange multipliers associated with a unilateral surface constraint onto a multivariate surface constraint Jacobian for the case where the two objects (finger and model) do not stick together. Advantages of our method are that the surface Jacobian is already being computed from an exact NURBS-NURBS collision update algorithm previously developed by the authors, and that the force response is accurate to numerical precision; no polygonal or numerical approximations are employed.
Force-Enabled Sculpting of CAD Models
Authors: Buttolo Pietro , Stewart Paul , Chen Yifan 
Published: November 2021

Abstract
Transferring geometrical information between Computer-Aided Design models and physical prototypes is a time-intensive task and as such is one of the critical bottlenecks in the automotive design process. Sculpting of free-form surfaces in force enabled CAD applications could bridge the gap between digital models and certain physical prototypes. In this paper a novel force-enabled surface manipulation method called stick-to-surface/stick-to-pen is presented. During sculpting, the haptic device is constrained to follow the virtual surface, and simultaneously the surface is controlled to follow the device. The trade-off between which follows which is managed by partitioning the Cartesian space into a browsing subspace and a manipulation subspace.
Stress Analysis of Adhesively Bonded Lap Joints of Hollow Shafts Subjected to Torsional Moments
Authors: Nakano Yuichi , Takagi Yukihisa , Sawa Toshiyuki 
Published: November 2021

Abstract
The stress and strain distributions in adhesively bonded lap joints of hollow shafts with dissimilar materials subjected to torsional moments are examined using an axisymmetric theory of elasticity. In the analysis, the joint is modelled as an elastic three-body contact problem, and the hollow shafts, and the adhesive are respectively replaced by finite hollow cylinders. In the numerical calculations, the effects of the ratio of Young’s modulus of the adhesive to that of the shaft, the overlap length, and the thickness of the adhesive on the stress distributions at the interfaces in the joint are clarified. It is shown that the shear stress becomes singular at the ends of the interfaces between the shafts, and the adhesive, and increases near the ends of the interfaces with a decrease of Young’s modulus of the shaft, and of the thickness of the adhesive. For verification of the stress analysis, the strain distribution at an outer surface of an adhesively bonded lap joint was measured and a fairly good agreement was shown by comparing the experimental result with the analytical one.
Opportunities for Crashworthiness Improvement Using Tube Hydroforming
Authors: Morphy Gary E. 
Published: November 2021

Abstract
The automotive industry has and continues to make advances toward the sometimes conflicting goals of make our vehicles safer to use, lighter and better able to perform while achieving attractive appearance and downward cost pressure.
Benefits that hydroforming offers that can improve crashworthiness are reviewed. Brief descriptions of 2 hydroforming methods are given followed by a more detailed examination of wall thickness and cross section expansion. Others include the influence of part design on forming pressure, materials that can be used and part surface complexity.
Design Issues in Tissue Engineered Cartilage Replacement
Authors: Andriacchi Thomas P. , Alexander Eugene J. 
Published: November 2021

Abstract
Tissue engineered replacement cartilage for the treatment of an arthritic joint must sustain the mechanical demands of normal function. Historically total joint replacement has been the primary method for the treatment of severely degenerated joints. The design of a tissue engineered cartilage replacement has a number of parallels with the design of a total joint replacement. Therefore, it is useful to examine the design process of a total joint replacement in the context of designing a tissue engineered cartilage replacement. This presentation will examine the design requirements for the replacement of articular cartilage at the knee.
Morphological Age-Depended Development of the Human Carotid Bifurcation
Authors: Seong Jaehoon , Wakhloo Ajay K. , Lieber Baruch B. 
Published: November 2021

Abstract
The development, significance and function of the human carotid sinus are not clearly understood. The arterial wall of carotid sinus is densely enervated and it contains baroreceptive neural terminals. It has been hypothesized that the dilation, which may involve all vessels of the carotid bifurcation, serves to support pressure sensing. Another hypothesis based on phenomenological observations presumes that the function of the sinus is to slow the blood flow and reduce the pulsatility in order to protect the brain (1). Yet another postulate states that the sinus is an ontogenetic or phylogenic residual. More recently, in vitro and computational models have been used to investigate carotid hemodynamics. Complex flow patterns have been found in the carotid sinus. These patterns have been implicated in the carotid bulb heterogeneity and subsequent development of atherosclerosis at this site.
However, long term development of this unique sinus morphology has not been investigated. It is of both fundamental and clinical interest to form an understanding of the hemodynamics and developmental forces that play a role in remodeling of the carotid bifurcation and maturation of the sinus. This understanding can lead to better prognostication and therapy of carotid disease.
Therefore, a study of the morphological development of the human carotid bulb was initiated. Carotid bulbs from various human developmental stages were evaluated to test the hypothesis that morphology of the sinus reflects an acclimated change in response to alterations in cerebral blood supply with aging. This acclimation attempts to diminish hydraulic losses in the carotid bifurcation through reduced flow disturbances. Under basal conditions, a high level of blood supply to the brain is maintained that consumes about 15% of cardiac output. Furthermore, it may protect the brain from highly pulsatile blood flow conditions and/or the sinus wall from high shear stress.
Initially, we analyzed the sinus morphology and the angle of the carotid bifurcation in four human developmental stages, namely newborn, pediatric, adolescent and adult patients (Groups I, II, III, and IV, respectively). The analysis was performed using biplane digital subtraction angiograms to characterize changes that occur as the brain matures.