bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling of the Electro-Mechanical (E/M) Impedance Response of a Damaged Composite Beam
Authors: Giurgiutiu Victor , Rogers Craig A. 
Published: December 2021

Abstract
The electro-mechanical (E/M) impedance method has gained acceptance as an effective technique for structural health monitoring, damage detection, and failure prevention. In spite of extensive experimental validation of this novel method, very little work has been dedicated to its modeling. This paper develops a model of the E/M impedance response of a damaged composite beam interrogated by a PZT wafer active sensor. The electromechanical model for the interaction between the beam and the active sensor is developed from first principles. The effective axial force and bending moments induced by the PZT wafer into the beam are considered. Equations of motion for the flexural vibrations of a composite beam under moment excitation are developed. Solution in terms of normal modes with internal damping is obtained. The resulting response and the applied force are utilized to deduce general expressions for pointwise dynamic stiffness and pointwise dynamic compliance. Effective stiffness of the PZT wafer is also calculated, and the complex stiffness ratio for the PZT-structure interaction is determined. Hence, the complex electro-mechanical impedance and admittance are deduced.
A numerical example is given to illustrate the method and test its effectiveness. It is found that the real part of the effective pointwise dynamic stiffness interacts at par with the PZT stiffness at structural resonance frequencies. The imaginary part of the complex stiffness ratio directly reflects the pointwise structural resonances. Consequently, the real part of the electro-mechanical impedance directly reflects the pointwise structural resonances too. The same behavior is also found in the electro-mechanical admittance. Thus, the real part of the E/M impedance and the real part of the E/M admittance are found to be direct measures of the structural response, reflective of damage presence.
Impact Identification for Metallic Plate Using Distributed Smart Materials
Authors: Peelamedu Saravanan M. , Naganathan Nagi G. 
Published: December 2021

Abstract
In the design of automobiles, occupant safety during a crash is an important factor in consideration. The vehicle should identity impact, handle passenger safety through deployment of various safety restraint systems, and steer away the vehicle from impact. With this background, this work is to find the impact location, magnitude, and identify damage on a metallic structure.
The first phase through the use of experimental and FEA is to demonstrate the piezoceramic sensor effectiveness and its ability to handle different orientations. In the second phase, the dynamic plate equation for impact is developed using Mindlin plate model, Ritz energy approach, and Hamilton principle. In the third phase, different forward model case studies of static and dynamic compared with FEM and theoretical work. The final phase, is to find frequency of undamaged and damaged plate area of 0.1% and 1% for various locations, to help in damage or no damage identification scenario.
Biviscous Damping Behavior in Electrorheological Dampers
Authors: Wereley Norman M. , Lindler Jason 
Published: December 2021

Abstract
Electrorheological (ER) and magnetorheological (MR) flow mode dampers can exhibit biviscous damping behavior. Such behavior is characterized by a high damping preyield region for low velocities, with a transition to a relatively lower postyield damping, once the damper force exceeds the yield force of the damper. The biviscous damping behavior is a result of leakage, defined as a second path of Newtonian flow in addition to the Bingham plastic flow through the ER or MR valve. We experimentally demonstrate such bilinear damping behavior in a monotube ER shock absorber. The ER fluid is typically assumed to behave as a Bingham plastic fluid. Thus, two perspectives are examined to predict damping performance of the ER monotube shock absorber. First, the quasi-steady Bingham plastic analysis is coupled with a mechanical analysis of the leakage effects. Second, a biviscous constitutive perspective is described that allows for the leakage effects to be described as an apparent preyield viscosity of the ER fluid. Both perspectives prove to be useful in describing damping performance of the ER monotube shock absorber.
A Method for Measuring Short Crack R-Curve Behavior of Ferroelectric Ceramic
Authors: Chen Wei , Lynch Christopher S. , Lupascu Doru 
Published: December 2021

Abstract
This work describes a method for measurement of R-curve behavior in ferroelectric ceramics using four point bending specimens with a controlled surface crack. A short surface crack is produced by a Knoop indentation and the damage zone is polished away. The results are compared for two compositions of lead lanthanum zirconate titanate (PLZT), an elastio-plastic ferroelectric composition and a linear elastic electrostrictive composition. R-curves are measured in the crack length regime of 0.1 to 0.8 mm. The ferroelastic composition displays a toughness increase from 0.7 to 1.4 MPam. The linear elastic composition displays a constant toughness of between 0.6 and 0.7 MPa√m. The R-curve behavior of PLZT 8/65/35 is attributed to ferroelastic toughening.
Adaptive Shape Control for an SMA-Actuated Aerofoil Rib Structure
Authors: Webb Glenn V. , Lagoudas Dimitris C. , Kulkarni Mayur 
Published: December 2021

Abstract
This paper presents a methodology for shape control of a cantilevered beam with multiple SMA wire actuators. Previous research by the authors has centered on adaptive control of a single SMA actuator to elicit a desired structural response. The approach for a single SMA actuator is extended for multiple SMA actuators, which increases the complexity of actuator control. The effect of one actuator on the structural deformation is coupled with the effects of the other actuators. The cantilevered beam experiment is provided as a proof of concept for shape control strategies which can be applied to the more complicated aerofoil rib structure.
Modal Voltages of Linear and Nonlinear Structures Using Distributed Artificial Neurons
Authors: Howard R. V. , Chai W. K. , Tzou H. S. 
Published: December 2021

Abstract
Laminated or embedded distributed neurons on structural components serve as in-situ sensors monitoring structure’s dynamic state and health status. Thin film piezoelectric patches are perfect candidates for this purpose. A generic piezoelectric neuron concept is introduced first, followed by definitions of neural signals generated by an arbitrary neuron laminated on a generic nonlinear double-curvature elastic shell. This generic neuron theory can be applied to a large class of linear and nonlinear common geometries, e.g., spheres, cylindrical shells, plates, etc. To demonstrate the neuron concept, an Euler-Bernoulli beam laminated with segmented neurons is studied. Neural signals and modal voltages are presented. Theoretical results are compared with experimental data favorably.
Zero Gravity Validation of Smart Aperture Antennas
Authors: Yoon Hwan-Sik , Washington Gregory 
Published: December 2021

Abstract
In this study, a smart aperture antenna of spherical shape is modeled and experimentally verified. The antenna is modeled as a shallow spherical shell with a small hole at the apex for mounting. Starting from five governing equations of the shallow spherical shell, two governing equations are derived in terms of a stress function and the axial deflection using Reissner’s approach. As actuators, four PZT strip actuators are attached along the meridians separated by 90 degrees respectively. The forces developed by the actuators are considered as distributed pressure loads on the shell surface instead of being applied as boundary conditions like previous studies. This new way of applying the actuation force necessitates solving for the particular solutions in addition to the homogeneous solutions for the governing equations. The amount of deflections is evaluated from the calculated stress function and the axial deflection. In addition to the analytical model, a finite element model is developed to verify the analytical model on the various surface positions of the reflector. Finally, an actual working model of the reflector is built and tested in a zero gravity environment, and the results of the theoretical model are verified by comparing them to the experimental data.
Experimental Investigation of Nonlinear Vibration Absorbers
Authors: Agnes Gregory S. 
Published: December 2021

Abstract
An experimental investigation of the performance of nonlinear vibration absorbers on nonlinear systems was performed. The results verify the previous analytical findings of the authors. Initially, for low excitation, the nonlinear absorber gives better results than the nonlinear case. However as the forcing level is increased, the system response undergoes a series of Hopf bifurcations leading to chaotic behavior and poor absorption of the vibrations.
Viscothermal Damping in Thin Gas or Fluid Layers
Authors: Beltman W. M. , Basten T. G. H. , Tijdeman H. 
Published: December 2021

Abstract
This paper deals with viscothermal wave propagation, including acousto-elastic interaction. For wave propagation in thin gas or fluid layers, the effects of viscosity and thermal conductivity have to be accounted for. These effects can introduce a significant dissipation of energy. A model to describe viscothermal wave propagation was developed. It includes the effect of inertia, viscosity, compressibility and thermal conductivity. It was written in terms of dimensionless parameters. These parameters govern the validity of simplifications and they can be used to put models into perspective. The viscothermal model is validated with specially designed experiments. A numerical finite element model was developed that includes the full acousto-elastic coupling. This model was also validated with experiments. The influence of barriers in a thin layers was investigated experimentally. Finally, the new techniques were applied to a number of practical problems: the damping of double wall panels and the dynamical behaviour of a folded array of solar panels during launch.
Modified Extended Thermodynamic Model for Material Damping
Authors: Lu Xia , Hanagud S. 
Published: December 2021

Abstract
During the process of damping of a structure, the mechanical energy is converted to thermal energy. Yet, the most commonly used model for material damping is the linear viscous damping. There are many attempts to develop thermodynamic models for damping. To adequately describe damping, we need more variables than the classical state variables. A simple thermodynamic model that is based on the framework of extended non-equilibrium thermodynamics is presented. Heat flux, non-equilibrium stress field and the associated non-equilibrium internal energy are used as additional variables. Longitudinal vibrations of a uniform rod are studied to present the flexibility of thermodynamic modeling for material damping.
Mass Transfer Enhancement in an Intravenous Membrane Oxygenator Induced by a Pulsating Balloon
Authors: Guzmán Amador M. , Amon Cristina H. 
Published: December 2021

Abstract
The Intravenous Membrane Oxygentor (IMO) is a device that consists of hundreds of hollow fibers and an elastic, non-permeable, balloon that is positioned within the vena cava. The balloon inflates and deflates rhythmically to a given amplitude and frequency to generate cross flow, promote blood mixing, and enhance the gas exchange. The IMO has been designed to provide temporarily up to 50% of the O2 and CO2 exchange requirements to patients who suffer Acute Respiratory Distress Syndrome (ARDS) [1–4]. This illness affects approximately 150,000 people per year in the U.S. and is characterized by non-cardiogenic pulmonary edemas and a rapid and progressive malfunctioning of the lung [4]. The IMO device is an alternative therapy to conventional treatments such as mechanical ventilation and extracorporeal membrane oxygenation [5–7]. This paper reports the investigation of the flow and oxygen transfer characteristics of the IMO device shown in Fig. 1(a) and describes the numerically obtained flow patterns and the oxygen transfer characteristics for stationary and pulsating balloon regimes.
Analysis of Gender Based Thermal Regulation
Authors: Spieker Michael A. , Hayes Linda J. , Wissler Eugene H. , Colvin David P. 
Published: December 2021

Abstract
Significant qualitative and quantitative data from the literature suggests that men and women differ in their response to extreme thermal environments. It is apparent that women sweat less (Morimoto et al., 1967; Wyndham et al., 1965), and have a thicker subcutaneous fat layer (Wells, 1991) relative to men. Men, on the other hand have higher resting and working metabolic rates relative to women, which tend to increase their core body temperatures at a faster rate. A whole body thermal regulation model (Wissler, 1985) designed by Gene Wissler is used to analyze the gender based thermal responses of men and women subjected to medium-high work levels in several thermal environments. This study has important application in estimating how gender differences affect the potential work performance of men and women in extreme thermal environments.
Motion of Microcarriers in Rotating-Wall Vessels
Authors: Gao Hongxia , Ayyaswamy Portonovo S. , Ducheyne Paul 
Published: December 2021

Abstract
It is now widely acknowledged that the simulated microgravity environment of NASA-designed rotating-wall vessels (RWVs) offers great advantages for three-dimensional growth of mammalian cells. In the rotating-wall vessel, the solid body rotation is accomplished by horizontally rotating a vessel, which consists of a cylinder or two concentric cylinders and is completely filled with culture medium, at a constant rotational speed. Mixing and shear forces in the RWV are due to the microcarriers’ motion in the fluid, and the contact that the microcarriers occasionally make with the wall and each other [1]. Therefore, the motion of microcarriers in the rotating flow is of interest and important in the design of the rotating-wall vessel bioreactors and in the guiding of RWV cell culture experiments under optimal operating conditions.
Predictions of a single microcarrier migration inside the RWV have been described in our previous study [2]. However, the particle-wall and the particle-particle interactions were not considered. In this study, we numerically investigate the motion of microcarriers with the effects of the collisions under consideration.
Mechanical Recovery of Cultured Axons After Dynamic Stretch: Correlation to Cytoskeletal Changes
Authors: Meaney David F. , Ewoterai Inifome , Wolf John A. , Lusardi Theresa G. , Smith Douglas H. 
Published: December 2021

Abstract
In this study, we used a novel device to stretch cultured CNS axons up to 77% of their initial length under mechanical conditions mimicking traumatic injury. The morphological response immediately following stretch was recorded using video microscopy techniques, and the cytoskeletal response to stretch was examined using immunocytochemistry techniques. Below the threshold for primary axotomy, axons maintained their overall position on the substrate but displayed periodic distortions at points along their length. These strain induced changes in axonal morphology were observed at all applied strains used in the current study. Moreover, a large fraction of the cultured axons showed a relatively uniform frequency of distensions along their length; only a small minority of the axons in the field showed a few or single larger distension along their length. Interestingly, all axons showing distensions gradually recovered to a straightened pre-stretch shape over a period of 45 min, with most of the relaxation occurring in the first 20 minutes. Phenomenological models developed for the observed mechanical recovery phenomena suggest a molecular-based recovery process (τave ∼ 24 minutes) that is consistent with previous towed growth experiments on neurites. Unlike previous towed growth experiments, though, permanent changes in the neurofilamentous cytoskeleton were observed at 2 hr. post-stretch. These data suggest there is an endogenous mechanism for axons to regain morphology after stretch despite permanent changes to parts of the cytoskeleton that occur after even a single mechanical stimulus.
Vitrification Fulfills its Promise as an Approach to Reducing Freeze-Induced Injury in a Multicellular Tissue
Authors: Taylor Michael J. , Song Ying C. , Kheirabadi Bijan S. , Lightfoot Fred G. , Brockbank Kelvin G. M. 
Published: December 2021

Abstract
The destructive effect of extracellular ice formation in organized multicellular tissues is known to be a principal reason why conventional techniques of cryopreservation fail to provide effective protection during freezing. Avoidance of ice during cooling can physically be achieved by vitrification, which is the amorphous solidification of a supercooled liquid by adjusting the solute composition and cooling rate such that nucleation and growth of ice crystals is prevented. In principal a biological system can be stabilized in the glassy (vitreous) state without the inherent problems associated with crystallization and so-called solution effects injury that arise from the increased concentration of solutes due to removal of water as ice.
This study was designed to evaluate a vitrification approach to storing a vascular tissue model (rabbit jugular vein) compared with a standard commercial method used clinically and employing slow cooling (l°C/min) with dimethylsulfoxide (DMSO) as the cryoprotective agent (CPA). A baseline vitrification medium (designated VS55) was used to replace at least 50% of the tissue water with a combination of CPAs. and vitrification was achieved using a relatively high cooling rate (&gt; 40°C/min). After rewarming and removal of the CPAs. contractility of the blood vessel segments was evaluated in vitro using standard physiological response tests to a panel of reagents. The maximum contractions achieved in vitrified vessels were all greater than 80% of fresh matched controls with similar drug sensitivities. In contrast, frozen/thawed vessels exhibited maximal contractions below 25% of fresh matched controls with concomitant decreases in drug sensitivity.
This study clearly demonstrates a significant benefit of vitrification compared with conventional freezing and thawing for preserving smooth muscle contractile function of preserved blood vessels. Vitrification may prove to be an effective way to minimize the deleterious effects of freezing and thawing in cryopreserved tissues, or engineered tissue constructs.
Three-Dimensional Microstructure of Muscle Tissues During Freezing and Thawing
Authors: Ishiguro Hiroshi , Horimizu Takashi 
Published: December 2021

Abstract
Three-dimensional behavior of ice crystals and cells during the freezing and thawing of biological tissues was investigated microscopically in real time by using a confocal laser scanning microscope (CLSM) and a fluorescent dye, acridine orange (AO). Fresh tender meat (2nd pectoral muscles) of chicken was stained with the AO in physiological saline, and then frozen and thawed in a uniform temperature under two different thermal protocols: a) slow-cooling and rapid-warming and b) rapid-cooling and rapid-warming. The CLSM noninvasively produced tomograms of the tissues to clarify the pattern of freezing, morphology of ice crystals in the tissues, and the interaction between ice crystals and cells.
Heat Transfer in Laminar Tube Flow of a Suspension Containing Microencapsulated Phase-Change Material
Authors: Mulligan J. C. , Boyer D. K. 
Published: December 2021

Abstract
A numerical formulation of the energy equation is developed for the laminar flow of a MEPCM fluid in a tube at a constant velocity and subjected to a constant and uniform wall heat flux. MEPCM fluids are phase-change fluids that are suspensions comprised of particles of microencapsulated phase-change material (MEPCM) in a carrier fluid. The thermodynamic behavior of MEPCM fluids is modeled for both melting and crystallization and included in an enthalpy formulation of the energy exchanges. A particular phase-change case involving a microPCM fluid is then solved for conditions that produce melting and crystallization of the phase-change material. Heat transfer results are presented which show that the MEPCM phase-change characteristics, along with system parameters, have significant effects on the potential of MEPCM fluids to improve heat transfer and facilitate enhanced temperature control in pumped loops.
Use of MicroPCMs in Agricultural Applications
Authors: Cartwright D. Kelly , Bryant Yvonne G. , Colvin David P. 
Published: December 2021

Abstract
Microencapsulated phase change materials were tested in several agricultural systems, including mycoherbicide development, alleviation of heat stress in agronomic crops and frost prevention. The primary constraint to development of mycoherbicides is the lack of free moisture for weed infection and excessively high temperatures. Using microencapsulated water, the time of free moisture exposure necessary for infection by Colletotrichum capsici (mycoherbicide) on pitted morningglory was reduced by 56%, while use of a customized microPCM to regulate temperature increased effectiveness as much as 70%. A combination of the microencapsulated water and microPCM also improved disease severity significantly. The technology also improved control by C. malvarum on prickly sida. Although variable, microPCMs reduced the severity of frost damage on tomatoes and impatiens with temperature decline inside specific plant parts treated with a variety of microPCMs slowed dramatically. Research on the use of microPCMs to protect plants from heat stress is currently ongoing. The potential for microPCM use in agricultural is high.
Test Geometries for Bondline Cracked Photoelastic Models; Preliminary Results
Authors: Smith C. W. , Gloss K. T. , Liu C. T. 
Published: December 2021

Abstract
By interrogating polyurethane specimens containing bondlines with cracks photoelastically, the authors are conducting a study of the effect of fixed ends upon the stress intensity factor (SIF) for double edge cracked specimens for test specimens of relatively short height. Preliminary results suggest that, while the presence of the bondline increases the SIF with increasing crack length, reducing the specimen height will reduce the SIF level for all crack lengths.
Numerical Study for Global Detection of Cracks Embedded in Beams
Authors: Lipsey S. A. , Kwon Y. W. 
Published: December 2021

Abstract
Damage reduces the flexural stiffness of a structure, thereby altering its dynamic response, specifically the natural frequency, damping values, and the mode shapes associated with each natural frequency. Considerable effort has been put into obtaining a correlation between the changes in these parameters and the location and amount of the damage in beam structures. Most numerical research employed elements with reduced beam dimensions or material properties such as modulus of elasticity to simulate damage in the beam. This approach to damage simulation neglects the non-linear effect that a crack has on the different modes of vibration and their corresponding natural frequencies. In this paper, finite element modeling techniques are utilized to directly represent an embedded crack. The results of the dynamic analysis are then compared to the results of the dynamic analysis of the reduced modulus finite element model. Different modal parameters including both mode shape displacement and mode shape curvature are investigated to determine the most sensitive indicator of damage and its location.