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Aerospace Thermal structures and materials for a New Era

丛书名： Progress in Astronautics and Aeronautics

1995年

作者： Earl A. Thornton

ISBN: (数字)9781600866364

ISBN: (纸本)9781563471827

Presenting recent advances in technology for high temperature structures and materials, this book will be of great interest to engineers and material scientists working on advanced aeronautics and astronautics projects that involve elevated temperatures. Other topics discussed include high-speed flight in the atmosphere, propulsion systems, and orbiting spacecraft. The latest research is compiled here in 19 papers written by various experts from all over the world. Complete with figures, graphs, and illustrations, this compilation of research is an essential volume for all engineers and scientists involved in aerospace thermal structures and materials. * Includes hundreds of figures, graphs, and illustrations. * Includes papers by leading experts detail the latest research and innovations. * Essential for all scientists and engineers involved in aerospace thermal structures and materials.

关键词： Acoustics Aeroacoustics Aerodynamics Aeronautical Engineering Aeronautics Aerothermodynamics Airbreathing Jet Engine Aircraft Components and Structure Aircraft Design Aircraft Engines Aircraft Operations and Technology Aircraft Wing Design Aircrafts Alloys Aluminium Alloys Annealing Applied mathematics Beam (structures) Buckling Analysis Combustion Chambers Combustors Composite materials Composite structures Compressors Computational Fluid Dynamics Conservation of Momentum Equations Continuum Mechanics Convection Coolant Cooling Technology Cryogenics Cylindrical Shell structures Deformation Deformation Mechanisms Earth Observation Satellite Energy Energy Conversion Energy Economics Energy Forms, Production and Conversion Equations of Fluid Dynamics Failure Analysis Fatigue (materials) Finite Difference Method Finite Element Method Finite Element Software Flexible and Active structures Flow Regimes Fluid Dynamics Fracture Mechanics Gas Turbine General Physics Glass Fiber Heat Conduction Heat Engines Heat Transfer Heat Treatment Jet Engines Material Properties materials materials Synthesis and Processing materials and Structural Mechanics Mathematical Analysis Mechanical Properties Mechanical and Structural Vibrations Mesh Generation Metal Matrix Composites Metallurgy Metalworking Microscopy Numerical Analysis Plasticity Polymer Matrix Composites Propulsion and Power Quenching Radiative Heat Transfer Rocket Engine Rocketry Satellites Shell structures smart structures and materials Solid Mechanics Space Systems Space Systems and Vehicles Spacecraft Design Spacecrafts Stress-Strain Analysis Structural Analysis Structural Design and Development Structural Engineering Structural Kinematics and Dynamics Structural Material Properties Structural Mechanics Structural System structures, Design and Test Thermal control and Protection Thermal Effects Thermal Insulation Thermal Measurement Thermal Modeling and Analysis Thermodynamic Properties Thermodynamics Thermophysical Properties Thermophysics and Heat Transfer Titanium A

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Intelligent control and actuators for structures

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smart materials and structures 1995年第1 A期4卷 A132-A139页

作者： Shoureshi, Rahmat Colorado Sch of Mines Golden United States

Recent advances in the areas of intelligent control, artificial intelligence, microprocessor technology, and smart materials have provided a strong foundation for the development and realization of 'intelligent structures'. This paper presents an integrated approach to the concept of intelligent structures and formulates a framework for the development of such structures. Furthermore, the concept of an adaptive, semi-active actuator for implementation of the proposed intelligent controller is presented.

关键词： Intelligent structures

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Missile flight control using active flexspar actuators

Missile flight control using active flexspar actuators

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smart structures and materials 1995: smart structures and Integrated Systems

作者： Barrett, Ronald M. Gross, R.Steven Brozoski, Fred Auburn Univ. Auburn AL USA

ISBN: (纸本)0819417920

A new type of subsonic missile flight control surface using piezoelectric flexspar actuators is presented. The flexspar design uses an aerodynamic shell which is pivoted at the quarter- chord about a graphite main spar. The shell is pitched up and down by a piezoelectric bender element which is rigidly attached to a base mount and allowed to rotate freely at the tip. The element curvature, shell pitch deflection and torsional stiffness are modeled using laminated plate theory. A one-third scale TOW 2B missile model was used as a demonstration platform. A static wing of the missile was replaced with an active flexspar wing. The 1' × 2.7' active flight control surface was powered by a bi-morph bender with 5-mil PZT-5H sheets. Bench and wind tunnel testing showed good correlation between theory and experiment and static pitch deflections in excess of ±14°. A natural frequency of 78.5 rad/s with a break frequency of 157 rad/s was measured. Wind tunnel tests revealed no flutter or divergence tendencies. Maximum changes in lift coefficient were measured at ΔCL = ±.73 which indicates that terminal and initial missile load factors may be increased by approximately 3.1 and 12.6 g's respectively, leading to a greatly reduced turn radius of only 2,400 ft.

关键词： Missiles

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Nonlinear error signal extraction technique for real-time digital automatic control of optical interferometers

Nonlinear error signal extraction technique for real-time di...

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smart structures and materials 1995: smart Sensing, Processing, and Instrumentation

作者： Barone, Fabrizio Calloni, E. Di Fiore, Luciano Grado, Aniello Milano, L. Russo, G. Istituto Nazionale di Fisica Nucleare and Univ. di Napoli Napoli Italy

ISBN: (纸本)0819417939

In this paper we describe the non linear error signal extraction, which is an efficient and robust technique for the automatic control of optical interferometers. It represents a global solution to the problem of the longitudinal error signal extraction also when the uncontrolled optical system spans hundreds of fringes. This technique basically uses classic modulation techniques (phase modulation, mechanical modulation, etc.), but extends their range of validity using also the information available at the output photodiode. We have digitally implemented such technique following modular hardware and software architectures. In fact, the hardware consists of commercial VME boards for A/D and D/A conversion and processing, housed in standard VME crates, while the software algorithm is written in standard C language for portability and easy integration within digital control architectures.

关键词： Interferometers

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Experimentation in system identification and adaptive controller design using the ASTREX

Experimentation in system identification and adaptive contro...

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Proceedings of the 36th AIAA/ASME/ASCE/AHS/ASC structures, Structural Dynamics, and materials Conference and AIAA/ASME Adaptive structures Forum. Part 1 (of 5)

作者： Narula, Kanika Jakubowski, Amy Helferty, John J. Temple Univ Philadelphia PA United States

A flexible `smart' strut, an Advanced Composite with Embedded Sensors and Actuators (ACESA), located on the Advanced Space structure Technology Research EXperiment (ASTREX) facility was used as a testbed to identify a state space model using the Eigensystem Realization Algorithm (ERA) for the purpose of testing a recently developed adaptive Zero Annihilator Periodic (ZAP) controller for vibration suppression. Unlike most conventional adaptive controllers, the adaptive ZAP can be applied to a nonminimum phase system or a system with poorly damped zeros without violating a stable invertibility condition. Therefore, an identification experiment was specifically designed to retrieve input/output data from the strut that would yield a system with poorly damped zeros. During the identification process, a recently developed error function (Total Truncation Error) was employed for determining the order of the system. Though the ZAP controller is adaptive in nature, the identified model was necessary to provide a `good' initial guess of the control gains.

关键词： Vibration control

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Vibration suppression of fixed-time jib crane maneuvers

Vibration suppression of fixed-time jib crane maneuvers

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smart structures and materials 1995: Industrial and Commercial Applications of smart structures Technologies

作者： Parker, Gordon G. Petterson, Ben Dohrmann, Clark R. Robinett, Rush D. Sandia Natl. Labs. Albuquerque NM USA

ISBN: (纸本)0819417963

A jib crane consists of a pendulum-like end line attached to a rotatable jib. Within this general category of cranes there exist devices with multiple degrees of freedom including variable load-line length and variable jib length. These cranes are commonly used for construction and transportation applications. Point-to-point payload maneuvers using jib cranes are performed so as not to excite the spherical pendulum modes of their cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. The resulting maneuvers are therefore performed slowly, contributing to high construction and transportation costs. The crane considered here consists of a spherical pendulum attached to a rigid jib. The other end of the jib is attached to a direct drive motor of generating rotational motion. A general approach is presented for determining the open-loop trajectories for the jib rotation for accomplishing fixed-time, point-to-point, residual oscillation free, symmetric maneuvers. These residual oscillation free trajectories purposely excite the pendulum modes in such a way that at the end of the maneuver the oscillatory degrees of freedom are quiescent. Simulation results are presented with experimental verification.

关键词： Vibration control

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New adaptable reference model adaptive control for slewing control of a flexible beam with an unknown tip-load

New adaptable reference model adaptive control for slewing c...

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smart structures and materials 1995: smart structures and Integrated Systems

作者： Ho, Ming-Tsang Yang, Jackson C. Chew, Mason Univ. of Maryland/Coll. Park Gaithersburg MD USA

ISBN: (纸本)0819417920

Conventional model reference adaptive control (MRAC) requires perfect model matching condition as a prerequisite check for a successful controller design. Although such condition may be satisfied easily for some mechanical systems, it is extremely difficult for adaptive slewing control of a flexible beam with an unknown tip payload. The reason being, firstly, there must be as many actuators as the number of assumed vibration modes to be placed along the beam to provide bending moment. Secondly, if the first condition is satisfied, it would still result in very high feedback gains even for a very small variation of tip payload mass. Therefore the conventional MRAC scheme is physically unapplicable for such application. This paper addresses this issue and provides a solution to the general problem where the actuation power is limited such that the conventional MRAC scheme would not work. A new scheme called Adaptable Reference Model Adaptive control (ARMAC) differs from the conventional MRAC in that the reference model of the ARMAC is not fixed. The ARMAC inheres infinitely many model gain sets which depend on the estimation of tip payload mass. As the controller/estimator is searching for the true tip payload mass, the working reference model is also trying to fit itself into the best reference model possible. The ARMAC employs the `steepest descent' method which the general MRAC uses to search for the true tip payload mass without any explicit parameter estimation process. This way the ARMAC avoids the stringent perfect model matching requirement while preserving the direct adaptation nature of MRAC successfully.

关键词： Adaptive control systems

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Predicting the vibration characteristics of elements incorporating incompressible and compressible viscoelastic materials

Predicting the vibration characteristics of elements incorpo...

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smart structures and materials 1995: Passive Damping

作者： Chan, Yew Wing Oyadiji, S.Olutunde Tomlinson, Geoffrey R. Wright, J.R. Univ. of Manchester Manchester UK

ISBN: (纸本)0819417947

In order to predict accurately the vibration characteristics of viscoelastic elements and viscoelastically damped structures, the use of frequency-dependent parameters such as complex modulus and Poisson's ratio is important. Several techniques have been developed for measuring the frequency-dependent complex modulus of viscoelastic materials. However, the accurate determination of Poisson's ratio of viscoelastic materials is much less developed. This quantity is important as its commonly quoted value of 0.5 can be very different when a viscoelastic material is in its transition or glassy region or if the material is compressible. In this paper, prismatic viscoelastic samples are employed to predict the value of Poisson's ratio using the finite element method (FEM). The transmissibility characteristics of these prismatic samples are established experimentally and FEM is used in conjunction with measured complex Young's modulus and iterated values of Poisson's ratio such that the predicted FEM results agree as well as possible with the experimental data. It is shown that the method suggested is able to predict accurately the Poisson's ratio of incompressible and compressible viscoelastic materials.

关键词： Vibration control

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OPTIMAL DEFLECTION control OF MULTI-SEGMENT TRAVERSING BEAMS

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smart materials & structures 1995年第2期4卷 75-82页

作者： BAZ, A CATHOLIC UNIV AMER DEPT MECH ENGNWASHINGTONDC 20064

Multi-segment smart traversing beams with built-in sensing and actuation capabilities have been considered in various critical applications where weight and deflection are of utmost importance such as in long support bridges. With such capabilities, lightweight smart segments can be added one at a time to extend the traversing beam over long gaps with minimal deflections and stresses. Each segment of the smart beam has a set of distributed wire sensors embedded in its bottom fibers to sense the beam deflection, and another set of wire actuators embedded in the top fibers to compensate for the deflections encountered. The theory governing the operation of this class of smart beams is developed using the finite element method. Optimum design strategies are then applied to determine the optimal control actions, at each segment, necessary to minimize the deflections over the entire beam span. Numerical examples are given to demonstrate the effectiveness of the strategies developed in controlling the deflection of traversing beams during launching or crossing over operations. The concepts presented in this paper can be applied to a wide range of bridges, material handling structures and large space structures.

关键词： Beams and girders

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Design of an embedded piezoceramic actuator for active control applications

Design of an embedded piezoceramic actuator for active contr...

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smart structures and materials 1995: smart structures and Integrated Systems

作者： Koopmann, Gary H. Lesieutre, George A. Yoshikawa, Shoko Chen, Weicheng Fahnline, John B. Pai, Suresh P. Dershem, Brian R. The Pennsylvania State Univ. University Park PA USA

ISBN: (纸本)0819417920

The design of a piezoceramic actuators which is to be embedded in a composite structure is examined. The actuator device must: (1) include a collocated accelerometer;(2) meet certain actuation authority (force, stroke) requirements;(3) be able to survive the embedding process;and (4) have a minimal effect on structural integrity. The need to accommodate an accelerometer limits the minimum thickness of the device. To ensure that the (brittle) piezoceramic material is not broken during the embedding process, it is encased within a frame which has been designed to protect the piezoceramic from short durations of high temperature and pressure. Additionally, the frame is used to apply a compressive prestress to the piezoceramic, ensuring that the piezoceramic is protected from tensile stresses encountered in the operating environment. The output strain levels of the piezoceramic are maximized by using a co-fired stack (178 layers) oriented such that the piezoceramic is excited in the 3 - 3 direction. Because the layers of the piezoceramic stack are to be driven at high voltages, a special high power amplifier was designed which can source the current required by the actuator. The performance of the actuator alone has been tested by driving it uniaxially into a known impedance and measuring the output force and displacement at low frequency. Results form the tests and associated models are presented, which demonstrate the performance capabilities of the actuator.

关键词： Actuators

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