bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of Nonlinear Aeroelastic Systems
Authors: Namachchivaya N. Sri , Lee A. 
Published: March 2022

Abstract
This paper investigates the effects of nonlinearities on the dynamics of flat panels in supersonic flow and presents new bifurcation results for a fairly general nonlinear aeroelastic system. In order to obtain these results we use the method of normal forms, global bifurcation techniques, and various other dynamical systems tools. The first part of this paper deals with modeling unsteady aerodynamic forces and moments acting on flat panels undergoing arbitrary motion in supersonic flow. This modeling also considers the structural nonlinearities inherent in panels. While deriving the equations of motion, many in the past have neglected some nonlinear aerodynamic terms as insignificant from the modeling point of view. However, inclusion of these terms in the analysis may completely change the bifurcation behavior. In aeroelastic systems it is the nonlinear dissipative terms that can change the behavior, and it is essential to carefully model these terms in the physical problems. In the absence of dissipative terms the nonlinear system is reversible, which provides the governing equations with near integrable structure. Thus certain analytical methods are used to study the bifurcation behavior of the system near critical points. For general nonlinear fiat panels in supersonic flow, we present these effects as various bifurcation results due to symmetry-breaking imperfections. For aeroelastic systems, the reversible symmetry is broken by the addition of unsteady aerodynamic terms.
Two- and Three-Dimensional Analyses of Flow Around Airfoils Subjected to Forced Oscillation
Authors: Yokono Yasuyuki 
Published: March 2022

Abstract
This paper describes extensive computer-based analytical studies on the details of unsteady flow behavior around oscillating airfoils in turbomachinery. To consider the time-dependent motions of airfoils, a complete Navier-Stokes solver incorporating a moving mesh was applied, and the drag and lift coefficients for the cases of stationary airfoils and airfoils subjected to forced oscillation were examined. In order to clarify the interaction between the airfoil structure and the flow induced force, the exact fluctuation of the drag and lift coefficients with time needed to be determined. Although two-dimensional analyses have been performed for two-dimensional airfoils, it has suggested to be difficult to obtain the true separation vortex in such analyses because the vortex structure is essentially three-dimensional. Therefore, in the present study, a comparison was made between the two- and three-dimensional analyses for NACA0012 airfoils, and the separation vortex structure was examined in detail.
From the numerical results, it was found that the separation vortex consisted of large-scale rolls with axes in the span direction, and rib substructures with axes in the stream direction. The three-dimensional analysis could simulate these rolls and ribs, but the two-dimensional analysis was inadequate to realize this vortex structure. This is the main difference between the two- and three-dimensional analyses. In addition, the formation of ribs was found to be affected by the forced oscillation, and the transformation of rolls increased and the vortex structure became more fine as the oscillation frequency increased.
Design and Analysis of a Precision Multi-DOF Placement Device
Authors: Bahrami Hassan , Tzou H. S. 
Published: March 2022

Abstract
Piezoelectrics are increasingly being used in a large number of research explorations and engineering applications. In industry, piezoelectrics are widely being accepted as sensors, giving engineers more leverage to add new features to their products. In recent years, for example, distributed piezoelectric sensors and actuators are widely used in active vibration control of structures or precision mechatronic and structronic systems. In this paper, a piezoelectric quad-morph based multiple degrees of freedom (DOF) end-effector is designed and its multi-DOF precision placement operation is analyzed. This new multi-DOF cantilever beam design consists of multiple piezoelectric rectangular rods glued together, which provides a way to accurately position the end in space. Detailed analysis of this advanced composite structure is carried out by the finite element method incorporating the piezoelectric actuations.
Formulation and Solution of Equations of Motion of Structures With Elastic and Viscoelastic Components
Authors: Escobedo-Torres Javier , Ricles James M. 
Published: March 2022

Abstract
The equations of motion of structures with elastic and viscoelastic materials in the time domain are derived. The development is consistent with finite element formulations and leads to systems of equations where the matrices are symmetric, real, and composed of constant coefficients. Four-parameter fractional derivative models are used to model the frequency dependence of the linear viscoelastic materials since experimental data can be fitted successfully over wide frequency ranges. The resulting equations of motion are known as the elastic-viscoelastic equations of motion. Numerical procedures for solving the elastic-viscoelastic equations of motion in the time domain are developed. The closed-form, steady state solution of a single degree of freedom system is obtained in the frequency domain and is used to validate the results obtained by using the numerical procedures. The dynamic response of a multi-degree of freedom structure is obtained by using the numerical procedures.
Maximizing the Power Output of Air-Acoustic Actuator Arrays
Authors: Leo Donald J. , Paine Jeffrey S. N. 
Published: March 2022

Abstract
Maximizing the acoustic power output of air-acoustic actuator arrays is studied. The problem is shown to reduce to a generalized eigenvalue problem for the case of a planar structure radiating in an infinite baffle. The matrices of the eigenvalue problem are a function of the material and geometric properties of the plate, the location of the actuators in the array, and a nondimensional wavenumber. A simply-supported plate driven by an array of point force actuators is used as a representative example. The numerical study illustrates that the maximum sound power output of the array increases as the number of actuators increases, but the mass-normalized power efficiency of the array is not always maximized when the number of actuators in the array is increased.
Dynamics for Large Deflections of Laminated Composite Plates Including Piezoelectric Effect
Authors: Yu Y. Y. 
Published: March 2022

Abstract
Laminated composite plates have been treated systematically in our recent book (Yu 1996). In one of the chapters, classical and refined modelings for large deflections of laminates are formulated on the basis of nonlinear elasticity. In a separate chapter, similar modelings for large deflections of piezoelectric plates are dealt with on the basis of both nonlinear elasticity and piezoelectricity. In this paper we carry out a combined treatment of large deflections of laminated composite plates including the piezoelectric effect, through the use of constitutive relations.
Control of Distributed Actuators Without Electrodes
Authors: Main John A. 
Published: March 2022

Abstract
Presented in this paper is a new method for application of control signals to piezoelectric material patches that eliminates the need for both distributed electrodes and wire leads. The aim of this new method is to provide a design solution for smart structural applications that require a very high spatial resolution over a relatively large area. In such applications smart material patches with distributed electrodes are often an impractical choice because the number of separate electrodes and wire leads is driven extremely high.
This paper presents a smart material control concept that eliminates the need for separate electrodes and leads by using an electron gun to deposit control charges directly on the surface of the piezoelectric material. Since piezoelectric materials are dielectrics a surface charge accumulates due to the incident electron beam. Both positive and negative electric displacements can be applied by controlling the energy of the incident electrons. Also, charge can be applied over an area a few microns wide or centimeters wide by controlling the divergence of the electron beam with electron optics. The impact of these characteristics of electron gun control on the design of smart structural systems is discussed.
The general concept of the electron beam controlled adaptive plate is presented in this paper along with an engineering analysis that focuses on the materials, system, and control aspects of this new smart structures paradigm.
Simultaneous Optimum Design of Structure and H∞ Control System
Authors: Kawamura Shozo , Yasutake Toshio , Iwatsubo Takuzo 
Published: March 2022

Abstract
In this paper, some approaches for simultaneous optimum design of the structure and H∞ control system have been proposed. It was first shown that the selection of the frequency weighting functions influences on the control performance and the robust performance. Next, an approach for simultaneous optimum design has been proposed. In the approach, the frequency weighting function is optimized in the simultaneous optimum design. The results show that the values of the objective functions of individual and simultaneous optimum design are same. A new selection method of the objective function was then proposed. In the new method, every objective function is normalized in order to make the available range for all objective functions uniform. Numerical results show that using the proposed objective functions the simultaneous optimum design can be attained with a better design than the individual optimum design.
Advances in Adaptive System Applications at Daimler-Benz Research Labs
Authors: Martin Willi , Jänker Peter , Siegling Hans-Friedrich , Voggenreiter Heinz , Wang Ping , Trutzel Michael , Ahrendt Heinz , Klöppel Valentin 
Published: March 2022

Abstract
Within the past years the Daimler-Benz Research & Technology Department has initiated work to explore the benefits of adaptive materials and structures technologies for use in a broad range of modern transportation systems in the aerospace, automotive and railway industries.
This paper presents recent research activities focusing on two aerospace guidance concepts where the application of adaptive systems will play a major role: the “Adaptive Wing” and the “Adaptive Rotor Systems”.
The “Adaptive Wing” will incorporate “smart” technologies to control wing geometry to adapt to actual lift and load requirements. Various concepts for airfoil shape adaptivity are currently under investigation. The “Adaptive Rotor Systems” include an innovative type of individual blade control (IBC) with piezo-driven servo flaps built into the outer trailing edge of the rotor blades.
The presented research activities cover the field of multifunctional sensor and actuator systems based on adaptive materials and include basic material research, e.g. new approaches to fast reacting, high strain actuator materials, as well as innovative concepts for deformable “adaptive” structures up to proof-of-concept demonstrators at laboratory level.
Vibration Control via Active-Passive Hybrid Piezoelectric Network With Variable Resistance
Authors: Morgan Ronald A. , Wang K. W. 
Published: March 2022

Abstract
Active-passive hybrid piezoelectric networks (APPN) have been shown to be effective devices for vibration suppression. It has also been recognized that the resistor element in these devices, which is necessary to provide passive damping, can reduce the authority of the active control action. One possible method to improve upon this situation is to use a variable resistor in the RL shunt and on-line adjust the resistance based on feedback. However, the concurrent design method previously synthesized for APPN systems becomes difficult to implement when such a state-dependent and time-varying resistor is used. In this research, an effective and simple control law is developed for an APPN system with variable resistor. It is shown that by proper on-line adjustment of the variable resistor, the efficiency of the APPN system can be significantly increased.
Optimal Static Control of Statically Determinate Discrete Parameter Adaptive Truss Structures With t Linear Functions of Observed Response Components
Authors: Baltimore Craig V. , Utku Senol 
Published: March 2022

Abstract
Given a statically determinate truss adaptive system with q number of strain inducing actuators (one actuator per truss element) and t attributes (expressed in the form of linear functions of p observed nodal displacement components), such that t ≤ p ≤ q, this paper describes the optimal placement and selection of actuators. The placement and selection optimization is based on a minimization of a norm of the actuator induced strains, Δu. The minimization is performed using the largest magnitude of the tth order minor of the Jacobean of the attributes with respect to bar elongations. The relationship for determining the actuation, Δu, is also examined.
Experimental Validation of a Four Components Mixture Theory for Swelling Porous Media
Authors: Frijns Arjan J. H. , Huyghe Jacques M. , Janssen Jan D. 
Published: March 2022

Abstract
Biological tissues exhibit swelling or shrinking behaviour. This behaviour is caused by water binding. Biological tissues are able to bind water because of the fixed charges of the solid skeleton. These electrical charges are responsible for a variety of physical phenomena such as streaming potentials, diffusion potentials, electro-osmosis, electrophoresis and swelling.
Biological Gradient Regulated Predictive Model of Long Bone Growth
Authors: Taboas Juan M. , Lerner Amy L. 
Published: March 2022

Abstract
Morphogenesis is regulated by a complex interaction of factors that are intrinsic and extrinsic to the cells composing the organism (e.g. genetic programming, cytokine gradients, and applied mechanical/electrical forces). Mechanical stimulation has been shown to affect bone growth, but the interaction of mechanical forces with biological factors during the development of a cartilage anlage into adult form is not clear. During skeletal development, chondrocytes produce cartilage through differential cell growth, cell volume changes, and extracellular matrix secretion. Cartilage cells at the growth front undergo significant hypertrophy and later their surrounding matrix becomes mineralized. In turn, the mineral is resorbed by osteoclasts and new bone tissue is deposited by osteoblasts. During later stages of prenatal development, contraction of developing muscles applies significant loads to the skeleton which in turn affects the bone growth. This research attempts to elucidate how these processes are controlled by biologic factors in the absence of mechanical factors using a finite element (FE) model of the proximal tibia from a paralyzed chick embryo.
A High Accuracy Three-Dimensional Coordinate Digitizing System for Reconstructing the Geometry of Diarthrodial Joints
Authors: Haut Tammy L. , Hull Maury L. , Howell Stephen M. 
Published: March 2022

Abstract
Finite element modeling (FEM) in orthopaedic biomechanics requires a measurement technique to obtain accurate, three-dimensional (3-D) representations of diarthrodial joints [5], Accurate representations of joints, including soft tissue, articular cartilage, and bone are needed for FEM to be useful in the study of joint behavior and orthopaedic implants. Based on measuring the thickness of articular cartilage, the accuracy requirement for the measurement technique is 20 μm for a relative error of 1 percent.
Strain Environment Effects on Bone Regeneration and Tissue Differentiation During Distraction
Authors: Richards Mark , Goulet James A. , Goldstein Steven A. 
Published: March 2022

Abstract
Numerous clinical conditions continue to drive the need to understand, both quantitatively and mechanistically, the relationship between physical forces and bone formation and adaptation. The global objective of this research was to investigate the influence of strain environment on patterns of tissue differentiation. To test hypotheses related to this overall objective, experimental animal models which take advantage of the large volume of bone formed during distraction osteogenesis (DO) were used to show how physical forces and strains influence bone regeneration at different stages of the repair process. The approach taken was: 1) to manipulate the mechanical environment within the mesenchymal gap tissue in vivo in a known fashion; 2) to predict the resulting changes in stresses and strains by computational and analytic means; and 3) to assess the effects of these changes on patterns of tissue differentiation. Correlations between strain environment and tissue response were then sought to gain insight into the relationship between these two entities. This abstract summarizes work done to accomplish these objectives in two different areas. First, both the time-dependent and large-deformation behavior of the mesenchymal distraction gap tissue were evaluated. Second, the strain environment was manipulated in three specific ways, and the effects of these changes on patterns of new bone formation and precursor tissue differentiation were assessed.
On the Features and Assumptions of Bone Remodelling Theories: Part II — Density-Property Correlation and Influence of Remodelling Rate Function
Authors: Ben Souda Karima , Breton Pierre , Misra Aran K. , Ahmed Abdul M. 
Published: March 2022

Abstract
Application of theories simulating the bone remodelling process (BRP) requires a knowledge of the correlation between the density of bone and its mechanical properties. The correlations that have been used so far are based on the pooled results of measurements using both human and bovine specimens [1]. It has been shown, however, that pooling of such results from different species is inappropriate [2]. In view of this, the first objective of Part II of this study, is to establish the density-property correlations based exclusively on the experimental results from human bone specimens and to investigate the influence of the nature of the correlations on the stability of the simulated BRP.
Numerical Analysis of Oscillatory Flow and Gas Transport Through a Bifurcating Airway Model
Authors: Fujioka Hideki , Oka Kotaro , Tanishita Kazuo 
Published: March 2022

Abstract
The axial dispersion in the High-frequency oscillatory Ventilation (HFO) occurs due to the interaction between radial mixing and radially-nonuniform axial velocity profile. Since an aspect of the geometry of pulmonary airway is characterized by the curved portion in the pulmonary branch, the secondary flow in the airway plays the important role. Pedley and Kamm (1988) identified the significant effect of curvature on the gas dispersion, and discovered the convective resonance phenomena which gives a highly-peaked local maximum of axial gas transport when the calculating circulation time of secondary flow becomes identical to the cycle period. Subsequently Sharp et.al. (1991) experimentally confirmed the presence of convective resonance in a fully developed oscillatory flow in a curved tube. However, the curved portion of pulmonary branch is not long enough to generate the fully developed flow. This leads to the necessity of study about gas dispersion through a single bifurcating airway model. In the present study, oscillatory flow and gas transport of an incompressible, Newtonian fluid through a bifurcating airway model was numerically analyzed by solving the 3-dimensional Navier-Stokes equations. The employed model was based on Pedley’s report (1977), which comprises the curvature ratio to be 1/8 and the angel formed between the two daughter tubes to be 70 degree, whose radius is taken to be 0.78 times of the parent tube. The purpose of this study is to get the basic knowledge of the secondary flow generation for various Reynolds number, the velocity field and the axial gas transport in sinusoidal oscillatory flow through the bifurcation.
In Vitro-In Vivo Comparison of Prosthetic Heart Valve Performance
Authors: Hirt Felix , Botnar René , Baldwin Tim , Zhang Zhengji , Kepner Jeff , Boesiger Peter 
Published: March 2022

Abstract
The present investigation is focused on the significance of pulsatile in vitro flow measurements in the vicinity of prosthetic bileaflet heart valves at the aortic position. With the help of a pulse duplicator system and of optical LDA-technique, mean flow data were collected first. Then the blood flow patterns downstream of the same valve type was visualized in vivo by using a novel MRI-procedure. The application of both techniques under pulsatile flow conditions made the in vitro - in vivo comparison possible for the first time.
Measurement of Micro Flow Field Over Model Endothelial Cells
Authors: Fukushima Shuichiro , Inagi Kenichiro , Oka Kotaro , Tanishita Kazuo 
Published: March 2022

Abstract
Shear stress induced by blood flow on the arterial wall affect morphology and physiology of endothelial cells. The specific mechanisms alternating shapes and functions have not been identified in endothelial cells, because of the lack of a detailed description of the flow near the cell surface. Although the velocity profiles were numerically calculated (Barbee et al., 1995, Satcher et al., 1992, Yamamoto et al., 1996), experimental verification has not been accomplished.
Effect of Shear Stress on Mitochondrial Membrane Potential of Cultured Endothelial Cells
Authors: Kudo Susumu , Morigaki Ryoma , Ikeda Mariko , Oka Kotaro , Tanishita Kazuo 
Published: March 2022

Abstract
Endothelial cells line on the inner surface of the vascular is continuously exposed to shear stress by a blood flow in vivo. It is known that shear stress influences energy-dependent physical (Dewey et al., 1981, Levesque et al., 1985) and biochemical characteristics of endothelial cells (Arisaka et al., 1995). We, therefore, evaluated mitochondrial ATP synthesis activity by a confocal laser scanning microscope (CLSM) and a mitochondrial membrane potential probe, 5.5’, 6.6’-tetrachloro-1.1’,3,3’-tetrathylbenzimidazolocarbocyananine iodide (JC-1), when shear stress was loaded over cultured endothelial cells.
Intra-Uterine Fluid Motion Due to Myometrial Contractions: A Mechanism for Embryo Transport
Authors: Eytan Osnat , Elad David , Hartoov Joseph , Jaffa Ariel J. 
Published: March 2022

Abstract
The initial phase of a successful pregnancy is composed of a set of transport phenomena. The detached ovum is transported to the ampulla of the fallopian tube, where fertilization may occurs. If fertilization occurred, the embryo enters the uterine cavity within three to four days of ovulation after it has grown to a ball of cells of about 100 μm in diameter. In the uterus, the embryo is conveyed with the uterine fluid for another three to four days to a successful implantation site at the fundus, which is at the upper part of the uterus. The embryo does not have a self propelling mechanism, and thus, it is passively transported with the intra-uterine fluid, which is a highly viscous liquid. Fluid movements within the uterine cavity may be induced by myometrial contractions, which have been observed in non-pregnant uteri via in vivo measurements of intra-uterine pressures and high-speed replaying ultrasound images.