bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constitutive Modeling of 3-D Stress Induced Phase Transformation in Polycrystalline NiTi SMA
Authors: Lagoudas Dimitris C. , Qidwai Muhammad A. 
Published: December 2021

Abstract
A thermomechanical description of the martenstitic phase transformation and the associated shape memory effect in polycrystalline NiTi shape memory alloys (SMAs) is presented. The Kuhn-Tucker optimality conditions, constraints on the evolution equations for transformation strain find the form of transformation function are obtained naturally through the principle of maximum transformation dissipation. Various transformation functions are investigated and a generalized Drucker-Prager type transformation function is proposed. Numerical results of the model based on different transformation functions are compared with experimental results to determine their accuracy to predict SMA characteristics like tension-compression asymmetry, negative volumetric transformation strain and pressure dependence.
Optimal H∞ Control of Structural Vibrations Using Shape Memory Alloy Actuators
Authors: Sun Jian , Shahin Ali R. 
Published: December 2021

Abstract
This paper investigates robust control problem of structural vibrations using shape memory alloy (SMA) wires as actuators. The mathematical model for these SMA actuators is derived with emphasis in model uncertainty. The linearization of the relation between stress and temperature dynamics of SMA actuators is analyzed for active control. To handle the uncertainties caused by the linearization and the neglected high frequency dynamics, optimal H∞ control was employed to design a controller. An example is used to demonstrate the design procedures and the control system is tested in a nonlinear environment.
New Controller and Observer Design Methods Tailored to Smart, Flexible Structure Control Applications
Authors: Yedavalli Rama K. 
Published: December 2021

Abstract
In this paper, we summarize the research being carried out by the author and his group of graduate students on new control and observer design methods specifically tailored towards to control of smart and flexible structure applications. The new approaches are tailored to this specific application in the sense that they take into account the various types of available measurements and provide controllers and observers in terms of the various combinations of measurement variables. This approach of tailoring the controller and observer structure around the available measurement models has significant advantages over traditional approaches. Specifically these approaches introduce two new frameworks for controller and observer design, namely “Reciprocal State Space Framework” and “Matrix Second Order Framework”. Currently State Space Framework is a popular framework for control systems design in the sense that designers always transform the dynamic model of their application into state space form and then carry out the standard design techniques of this framework. However, we argue that there are many applications in which the dynamics, measurement models and performance constraints are such that it is unnecessary and cumbersome to force this transformation and instead the design can be carried out more easily in these newly introduced frameworks that are compatible with the plant dynamics, measurement models and performance constraints. Using these frameworks, simple control and observer designs are carried out with application to the problem of control of smart, flexible structures.
Modeling and Study of the Quasi-Static Behavior of Piezoceramic Telescopic Actuation Architectures
Authors: Berner Neal T. , Brei Diann E. 
Published: December 2021

Abstract
Piezoelectric stacks are often used in smart structures applications that demand high forces. However, there are numerous applications that require slightly more displacement than is available from stacks and the requirements allow room for some force to be sacrificed to obtain the displacement. A new type of piezoelectric actuation architecture, referred to as telescopic, was designed to meet the need for moderate displacement amplification (one to 20 times) while still producing large forces. This architecture internally leverages the piezoelectric strain by a series of cascading cylinders uniquely connected by end caps such that they “telescope” out when activated. This paper presents an analytical model to predict the force-deflection behavior of this actuator with compliant end caps. The compliance in the end caps governs the quality of the performance and is one of the main design drivers. To aid in evaluating this new architecture, the effect of other architectural losses, such as gap size and number of cylinders, is presented along with a comparison to the current state of the art.
A Composite Sandwich Structure With Embedded MEMS-Based Vibration Sensing
Authors: Pochiraju Kishore 
Published: December 2021

Abstract
This paper presents a sandwich composite architecture suitable for embedding MEMS-based accelerometers for long-term vibration monitoring or to act as sensors in adaptive structures. The presented architecture is designed around multi-axis accelerometers and temperature sensors that are commercially available. These devices also integrate sophisticated sensor compensation and data acquisition hardware into a single integrated circuit chip package. The paper presents the stiffness modeling of a sandwich composite with embedded accelerometers based on classical lamination theory. The first order shear deformation theory is used to compute the free vibration response of the sandwich composite. Solutions are presented for the free-vibration response of the sandwich beam under fixed-free boundary conditions. Results presented also include the response obtained from the MEMS-accelerometer when coupled to a thick cross-ply laminate under fixed-free boundary conditions.
Experimental Flutter and Buffeting Suppression Using Piezoelectric Actuators and Sensors
Authors: Suleman Afzal , Moniz Paulo A. , Costa António P. 
Published: December 2021

Abstract
Experimental buffeting and gust alleviation response results are presented for a sweptback flat wing model using piezoelectric actuators to control bending and wing tip camber shape. Model response was sensed by a small piezoceramic wafer mounted at the root. Two actuation strategies were implemented: the traditional actuators mounted at the root were used to provide structural damping, and a shape control mechanism using a pair of actuators near the wing tip were used to change the airfoil camber shape. Results obtained from wind-tunnel tests of the wing model are presented for the open- and closed-loop systems. The results of this experimental study show that piezoelectric actuation is effective in attenuating vibration and the wake-induced buffet response over the range of parameters investigated. Also, the airfoil camber shape control increases remarkably the efficiency of the system, by using a controlled change of lift in order to produce the required bending moments.
Vibration Control of Beams Using Electro-Magnetic Damping Treatment
Authors: Oh J. , Poh S. , Ruzzene M. , Baz A. 
Published: December 2021

Abstract
A new class of structural damping treatments is introduced. This class is the Electro-Magnetic Damping Treatment (EMDT) which relies in its operation on a viscoelastic damping layer sandwiched between two magnetic layers. Interaction between the magnets generates magnetic forces that enhance the compressional damping mechanism of the viscoelastic layer. With proper tuning of the magnetic forces, in response to the structural vibration, undesirable resonances and catastrophic failures can be avoided. The fundamentals and the underlying phenomena associated with the EMDT are investigated theoretically and experimentally.
A finite element model is developed to describe the interaction between the dynamics of flexible beams, the viscoelastic damping layer and the magnetic layers. The validity of the developed finite element model is checked experimentally using aluminum beams treated with EMDT patches. The beam/EMDT system is subjected to sinusoidal excitations and its multi-mode response is monitored when the magnetic layers are activated or not. Several control strategies are considered to activate the magnetic layers including simple PD controllers. The performance of the uncontrolled and controlled system is determined at various operating conditions. Comparisons with conventional Passive Constrained Layer Damping (PCLD) treatments emphasize the potential of the EMDT treatment as an effective means for controlling structural vibrations.
Control of Wave Propagation in Periodic Composite Rods Using Shape Memory Inserts
Authors: Ruzzene M. , Baz A. 
Published: December 2021

Abstract
Longitudinal wave propagation is controlled using shape memory inserts placed periodically along rods. The inserts act as sources of impedance mismatch with tunable characteristics. Such characteristics are attributed to the unique behavior of the shape memory alloy whereby the elastic modulus of the inserts can be varied up to three times as the alloy undergoes a phase transformation from martensite to austenite. With such controllable capability, the inserts can introduce the proper impedance mismatch necessary to impede the wave propagation along the rods.
An analytical model is presented to study the attenuation capabilities of the composite rods and to determine the influence of the various design parameters of the inserts that can control the width of the pass and stop-bands. The numerical results demonstrate the potential of shape memory alloys in controlling the dynamics of wave propagation in rods. Furthermore, the obtained results provide a guideline for designing inserts that are capable of filtering out selected excitation frequencies through proper adjustment of the geometry of the inserts as well as their activation strategies.
Active Damping by Acceleration Feedback Control and Redistribution of Stresses in the Structure
Authors: Bayon de Noyer Maxime P. , Roberts Patrick J. , Hanagud Sathya V. 
Published: December 2021

Abstract
In most structures, fatigue critical areas are associated with regions of high stresses. Passive stiffening of structures usually displaces these high stress regions. Thus, for most applications, active vibration control is preferred. However, the question of whether an active vibration control scheme involving a set of actuators will reduce stresses in the whole structure or create high stress areas in the vicinity of the actuators arises. In this paper, the stresses induced by an active vibration control system based on the use of an offset piezoceramic stack actuator with acceleration feedback control are investigated. Using a modal analysis of the actuator acting on a cantilever beam, a low frequency approximation of the actuator is developed in the form of a spring and two driving forces. Based on this approximation, a 3-D finite element simulation of the closed loop active vibration control system is developed and the closed loop stresses are studied.
Re-Evaluation of Arteriovenous Cooling of the Blood Supply to Human Brains
Authors: Zhu Liang 
Published: December 2021

Abstract
The purpose of this work is to evaluate the capacity of the heat loss from the carotid artery in human brain and thus, to provide indirect evidence of the existence of selective brain cooling (SBC) in humans during hyperthermia. A theoretical model is developed to describe the effects of local blood perfusion and vascular geometry on the thermal equilibration in the carotid artery based on the blood flow measurements and the anatomical vascular geometry in the human neck. A theoretical approach is used to estimate the potential for cooling of blood in the carotid artery on its way to the brain by heat exchange with its countercurrent jugular vein and by the radial heat conduction loss to the cool neck surface. It is shown that the cooling of the arterial blood can be as much as 1.3 °C lower than the body core temperature, which is in agreement with previous experimental measurements of the temperature difference between the tympanic and body core temperatures. The model also evaluates the relative contributions of countercurrent heat exchange and radial heat conduction to selective brain cooling. It is found that these mechanisms are comparable with each other. Results of the present study will help provide a better understanding of the thermoregulation during hyperthermia. They can be used to guide the design of future experimental investigations of the mechanism of SBC.
Freezing Response of Mammary Tissue: A Mathematical Study
Authors: Elliott Gloria D. , McGrath John J. 
Published: December 2021

Abstract
Cryosurgery, the use of low temperatures to devitalize neoplastic tissue, has become an accepted treatment modality for many cancers such as those of the liver and prostate. Recently, the application of cryosurgery to human breast malignancies has been explored (Staren et. al, 1997, Pham and Rubinsky, 1998). Breast cancer will affect 1 in 9 women over the course of their lifetime (American Cancer Society, 1997). Although there are a wide variety of therapies available to treat this disease, the broad pathological spectrum of patients with breast cancer necessitates newer and better treatments before these numbers will decline.
The composition of human mammary tissue is highly varied (age, body mass, and hormone dependent) making the application of cryosurgery to this tissue complex. Although the preponderance of breast cancer lesions occur in post-menopausal patients, women of all ages are affected by this disease. More importantly, lesions persist in all types of breast tissue. If cryosurgery is to become a viable therapy for breast cancer, it is important to understand the range of responses expected from the different tissue compositions, and, if relevant, identify the tissue types most suited to cryo-based therapies. To this end, an understanding of the response of these various classes of breast tissue to freezing can be accomplished using accurate heat and mass transfer models.
Based on a review of basic human breast histology during all stages of mammary gland development, several different categories of human breast tissue were chosen for constitutional analysis. The volumetric dominance of each of the different tissue constituents was determined and then using this information, the volume-averaged thermal properties for each category calculated. A preliminary analysis, utilizing basic heat conduction equations and effective heat transfer properties, was performed to understand if, in a pure conduction sense, the various categories of breast tissue would respond differently to the same applied freezing protocol, and if so, which components were thermally most relevant. This analysis, although not completely descriptive of the physical situation occurring during an actual cryosurgery protocol, represents the first steps in determining the morphological features of mammary tissue which must be taken into consideration in future modeling efforts.
Cryopreservation of an Engineered Skin Equivalent: The Apoptosis Paradigm
Authors: Baust John M. , Van Buskirk Robert G. , Baust John G. 
Published: December 2021

Abstract
The emergence of the tissue engineering sciences has led to an immediate need for cryopreservation protocols compatible with cell survival, cell-matrix binding and “scaffold” integrity. While numerous problems exist related to directional restrictions in cryoprotectant transport in tissue models, recent findings have demonstrated that the induction of specific molecular events, especially gene regulated cell death (apoptosis) is of significance. Accordingly, we report on a new strategy for the successful cryopreservation of a human skin equivalent.
The integration of an intracellular-type cryopreservation solution containing dimethyl sulfoxide with and without apoptotic inhibitors provides a successful model for tissue preservation. With optimized formulations, post-thaw improvement of viability upwards of three-fold has been demonstrated when compared with traditional preservation methodologies. We conclude that 1) the use of an intracellular-type cryopreservation medium, Hypothermosol®, can improve post-thaw tissue construct integrity and cell viability, and 2) the inclusion of apoptotic inhibitors significantly improves cryopreservation outcome.
Practical Considerations for Large-Scale Cryopreservation of a Tissue Engineered Human Dermal Replacement
Authors: Applegate Dawn R. , Liu Kang , Mansbridge Jonathan 
Published: December 2021

Abstract
Tissue engineering is redefining the field of transplantation by providing a readily available, off-the-shelf supply of consistent, easy to use, safe and effective products. Successful design and scale-up of both tissue growth and preservation processes have enabled maintenance of tissue integrity, functionality and viability from product manufacture to end-use and afforded clinical efficacy, feasibility of large-volume distribution and cost-effectiveness.
Advances in tissue preservation are being realized through extension of mathematical models and biological principles for isolated cells to bench-scale tissue systems. Hence, implementation problems inherent to large-scale systems are not often considered. Furthermore, the effects of preservation on tissues are not always tested in vivo. This paper addresses the practical obstacles to the design and implementation of a large-scale cryopreservation process. The effects of cryopreservation on in vivo tissue functionality including alteration of cell signal transduction pathways and expression of stress proteins in response to cryopreservation are also reviewed.
Thermal Stress Modeling of the Freezing of Biological Tissue
Authors: Rabin Yoed , Steif Paul S. 
Published: December 2021

Abstract
The extent of injury of biological tissues by freezing is influenced by many factors such as the cooling rate, the thawing rate, the minimal temperature achieved, the number of repeated freezing thawing cycles, and the presence of cryoprotectants. The mechanisms of cryo-destruction may generally be separated into two groups; the first is related to the freezing process within the phase transition temperature range (typically between 0 and −22°C), while the second group is related to further destruction after phase transition has completed. Destruction mechanisms of the first group are related to heat transfer, mass transfer, and chemical equilibrium in the intracellular and extracellular solutions. Destruction mechanisms after the phase transition has been completed are related to mechanical stresses in the frozen state. Mechanical stresses develop when changes in density occur nonuniformly in the tissue, a consequence of the presence of temperature gradients. The current presentation gives an up-to-date report on ongoing research to model the freezing of biological tissues and to measure their physical properties. The mechanical boundary condition at the freezing front is emphasized in this presentation, and examples for typical cases of cryosurgery and cryopreservation are discussed.
Interface Shape Control in a Cylindrical Directional Solidification Stage
Authors: Neils Christopher M. , Hayes Linda J. , Diller Kenneth R. 
Published: December 2021

Abstract
A numerical model of 1-D heat transfer and freezing in water has been used to support the development of thermal controls for an optical-axis directional solidification stage. By placing the observer’s point of view on the ice growth axis, this new cryostage improves the microsopic resolution with which cross-sections of growing ice dendrites can be observed. This arrangement also permits a large phase interface (1-cm diameter) so that the dendrite dimensions are not constrained by contact with the container surfaces. The numerical model simulated directional solidification with a constant chilling rate on one boundary. When the initial temperature was equal to the melting point, the interface speed was constant. An initial temperature above the melting point led to an accelerating interface when the second boundary was insulated and a decelerating interface when the second boundary temperature was fixed at the initial temperature.
An Experimental Investigation of the Effects of Microencapsulated Phase Change Material in Grinding Fluid Performance
Authors: Lee Jae M. , Shen Chi-Hung 
Published: December 2021

Abstract
This report documents an experimental study in the evaluation of the grinding performance of three metalworking fluids containing Microencapsulated Phase Change Material (MPCM) slurry. The results showed that wheel wear and surface finish were improved substantially in two cases while the performance became worse for the third fluid. There was significant deterioration of the microparticles because of the high shearing action of the circulating pump.
On Environmental Vibration Power Spectra and Accelerated Testing for Medical Devices
Authors: Wu Jingshu , Zhang Ruichong , Stevens Karl K. 
Published: December 2021

Abstract
This paper proposes field-testing-based power spectra of vibration in such environments as helicopters and ground vehicles. The spectra could then be used as important input data to guide accelerated testing, quality analysis and design for medical devices (or products) used in the aforementioned transportation means. Specifically, a broad spectrum of environmental vibration is first measured in a series of field vibration tests at various locations inside the transportation means and at different operational conditions (e.g., take-off, cruise, and landing conditions if medical devices are used in helicopters). Consequently, comprehensive field-testing-based power spectra are constructed, in an attempt to catch the inherent nature of random vibration environment in each and every type of the transportation means, which is not adequately specified in standard codes. As one of the applications of the proposed spectra, accelerated random vibration testing for medical devices used in either helicopters or ground vehicles is proposed, which could be used not only for product field life prediction but also for its consequent reliability analysis and design.
Smooth Asymmetric Indentation of a Finite Elastic Layer
Authors: Zhou Minggang , Schonberg William P. 
Published: December 2021

Abstract
Standard methods of indentation analysis use a beam theory solution to obtain an overall load-displacement relationship and then a Hertzian contact solution to calculate local stresses under the indenter. However, these techniques are only applicable in a fairly limited class of problems: previous modeling efforts have shown that the stress distribution in the region of contact will differ significantly from a Hertzian one when the contact length exceeds the thickness of the beam. In such cases, point contact can no longer be assumed and Hertzian relations are not valid. The indentation model developed herein is an improvement over current GLOBAL/LOCAL approaches in that it uses an elasticity solution to establish the load-displacement relationship at the contact site. The solution technique is applied to two end conditions: (1) simple supports, and (2) fixed ends. Superposition of appropriate elasticity expressions results in systems of Fredholm integral equations of the second kind that are solved numerically. Maximum contact stresses are obtained and compared with the predictions of the previous GLOBAL/LOCAL model. The validity of the solutions presented is assessed by comparing the results obtained to the predictions of modified beam theory solutions.