bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Turbine Engines: Compressors
Authors: Song Bo , Ng Wing F. 
Published: December 2010

Abstract
This chapter introduces important basics of the aerodynamics and thermodynamics of compressors. It starts with a classification of all types of compressors, showing various configuration features, operating principles, and applications. The two basic categories, positive displacement compressors and dynamic compressors, are described, followed by a breakdown of sub‐categories: reciprocating, rotary, axial, centrifugal, and diagonal compressors. Advantage and specialty of each type of compressor are explained. Following the discussion on the entire class of compressor family, the chapter then focuses on dynamic compressors only, since dynamic compressors are of primary use in gas turbine engines. The remaining sections of this chapter are dedicated to axial and centrifugal compressors. The aero‐thermodynamic process of a compressor stage is illustrated, using the one‐dimensional mean line approach, explaining how the gas state varies and how the work/energy conversion takes place through the compression. The definition of the compressor efficiency is derived and three commonly used definitions are discussed. The important concepts and terms usually encountered when dealing with compressor research and application are illustrated: surge, stall, choke, performance curve, performance map, operating range, and specific speed. The chapter closes with explaining the complexity, foreseeing the development trend, and providing reference sources of the subject.
Solid Propulsion: Ignition Transients and Combustion Instability
Authors: Schlueter Sam S. , Flandro Gary A. 
Published: December 2010

AbstractIgnition transients are a critical and complex period of operation in solid rocket motors. During the ignition interval, many factors combine that must be taken into account in the design of the entire system. There are many methods in use to analyze different aspects of the ignition processes, and the level of analysis complexity varies with need and available resources. These methods vary from empirically based sizing rules to complex physics‐based analyses. There are still many aspects of ignition transient behavior that have not been fully characterized, and research is continuing to fully understand all processes that occur during ignition transients in solid rocket motors. Combustion chamber pressure oscillations, often calledcombustion instability, can lead to dangerous vibration loads (“thrust roughness”) and elevation of motor operating pressure (“DC shift”). Frequencies are often associated with the chamber acoustic modes and cover a wide range from 10 Hz (in large solid rocket booster (SRB) motors) to over 30 kHz (in tactical rockets). Successful avoidance of these problems requires comprehensive understanding of a multitude of unsteady energy gain and loss mechanisms. The principal goals of current research are to predict (i) motor stability (tendency for oscillations to grow) and (ii) peak amplitude of the pressure oscillations throughout the motor burn.This information allows assessment of the threat to system operability and guides selection and application of corrective measures.
Combined‐Cycle Engines
Authors: Kanda Takeshi 
Published: December 2010

AbstractA combined‐cycle engine has two or more operating modes with a single flowpath. The motivation behind a combined‐cycle engine is to extend the engine's operating envelope and attain higher average performance. Several combined‐cycle engines and a combined engine system are presented. The rocket‐based combined‐cycle (RBCC) engine is a combination of a rocket engine and a ramjet engine. RBCC has wide operating range and structural simplicity, since there are no rotating parts. The drawback is a relatively lower specific impulse in the subsonic and transonic range. RBCC is suitable for the single‐stage‐to‐orbit (SSTO) vehicle due to its operability in low ambient pressure conditions and in space. The liquid air cycle engine (LACE) liquefies air using cryogenic propellants to reduce the onboard oxygen requirement. The advantages of LACE are reduced engine weight and wide operating conditions. However, owing to the low liquefaction efficiency of air, LACE suffers from low specific impulse and high fuel consumption. The turbo‐ramjet (TRE) and the air‐turbo‐rocket (ATR) engines employ turbocompressors to compress the airflow like in turbojet engines. Despite the advantage of increased specific impulse, both engines have low thrust to weight ratios. The dual‐mode scramjet engine like the RBCC has no moving parts. The combustion is subsonic in the ramjet mode and supersonic in the scramjet mode. The combination engine system, which mounts several engines on a vehicle, extends the operating range of the vehicle by operating appropriate engines according to the flight conditions.
Magnetoplasmadynamic Thrusters
Authors: Andrenucci Mariano 
Published: December 2010

AbstractA brief account is given initially of the origins of the MPD thruster concept. The nature of the Lorentz force, constituting the basic accelerating process exploited in MPD thrusters, is analyzed. A simple model of ideal self‐field MPD thruster is then considered; to illustrate the basic thrust law and the ensuing scaling trends characterizing this class of device. The behavior of real self‐field MPD thrusters is then described with regard to deviations from the ideal electrical characteristics, highlighting the Hall and the back‐EMF effects and the role of Alfvén's critical ionization velocity. Onset phenomenology and the critical onset parameter are then introduced. The main theories proposed to explain onset phenomena are summarized, with particular regard to mass starvation, and instabilities. Applied field MPD thrusters and lithium propellant self‐field and applied‐field devices are then described. The major R&D efforts so far undertaken in this field worldwide are shortly reviewed. Finally, some concluding remarks are made as to the status and prospects of MPD propulsion.
Torsion of Bars and Bending of Beams
Authors: Sun C.T. 
Published: December 2010

Abstract
Governing equations including derivations for structural members under torsion and bending are presented. The emphasis is placed on thin‐walled structures. The formulation for torsion problems is based on the Saint‐Venant torsion displacement assumption and solutions are obtained using the Prandtl stress function. Bi‐directional bending of beams is considered. Methods for calculating shear flows produced by combined bending and torsion loads are presented. The concept of shear center is discussed.
Dynamic Response Computations
Authors: Mignolet Marc P. 
Published: December 2010

AbstractThis chapter focuses on a detailed presentation of the methods available for the determination of the dynamic response of linear structural dynamic systems. Three particular situations are considered: free response, forced harmonic response, and forced response to an arbitrary loading. Approaches to determine these three different responses are presented for both classically and nonclassically damped systems using modal/eigenvector expansions. They transform multi‐degree‐of‐freedom systems into uncoupled second‐order (for classically damped systems) and first‐order (for nonclassically damped systems) differential equations the solution of which is presented and discussed. The determination of the steady‐state response to a harmonic loading through a frequency dependent impedance matrix is also demonstrated and the pros and cons of this method and the modal expansion strategy are discussed. The numerical evaluation of the response to an arbitrary loading from Duhamel's formula and by using step‐by‐step algorithms is discussed in details and some of the key properties of these methods are highlighted. It is finally demonstrated how to extend the previous discussion when the structure is excited by the motion of its supports. The finite element model of a wing is considered to exemplify the above methods and concepts.
Thermal Analysis
Authors: Rolfes Raimund J. 
Published: December 2010

Abstract
Important application areas for thermal analysis of aerospace structures are listed. The modes of heat transfer are described briefly. Starting from the laws of thermo‐dynamics the general heat conduction equation is derived. Fourier's law as the constitutive law for heat conduction is discussed, the appearance of the conductivity tensor for different material classes is described. Special methods for inhomogeneous and anisotropic materials (composites, sandwiches) as homogenization and thermal lamination theories are mentioned. Some typical temperature‐dependent thermo‐physical properties for aerospace materials are provided. Convective as well as radiative boundary conditions are treated. Radiation exchange between different structural parts is also covered. The general finite element equation system for nonlinear transient heat transfer problems is derived. Solution schemes including explicit and implicit time integration are derived and discussed.
Computational Fracture Mechanics
Authors: Brocks Wolfgang 
Published: December 2010

Abstract

A survey of fracture mechanics as an approach to characterise the safety and technical reliability of structures containing defects is given. The classical concepts based upon analytical asymptotic solutions of stress and strain fields at crack tips or, alternatively, on energy balances for cracked bodies are outlined. Characteristic parameters like stress intensity factor, energy release rate,
J
‐integral, CTOD etc. and the respective fracture criteria are presented. An introduction into the application of finite element methods for fracture problems is given. As fracture mechanics concepts find increasing applications for thin‐walled lightweight structures mainly in transportation industries, adapted new concepts like CTOA‐controlled crack extension and cohesive models have been developed, going parallel with improved capabilities and performance of computer codes.
Models for Delamination
Authors: König Manfred , D'Ottavio Michele 
Published: December 2010

AbstractThe chapter reviews some aspects of the broad and complex problem of delamination in composites. The focus is put on computational models for delamination predictions in the framework of a damage tolerance design. Both delamination initiation and its propagation under quasi‐static and cyclic loading are addressed, and their simulation by means of the Finite Element Method (FEM) is discussed. However, dynamic delamination propagation under impact loads, as well as the prediction of the effect of delamination on the ultimate failure, is not considered in this chapter.Basically, two modelling approaches are reviewed, namely Linear Elastic Fracture Mechanics (LEFM) in the form of the Virtual Crack Closure Technique (VCCT) and Continuum Damage Mechanics (CDM) applied to interface problems, that is, Cohesive Zone Models. Both approaches have recently been implemented in commercially available FE software. A summary of the respective peculiarities and limitations is presented. The significance of 2D laminated plate/shell elements that ensure the capturing of relevant through‐thickness effects is emphasized.
Static Buckling Tests of Aerospace Vehicle Structures
Authors: Hilburger Mark W. 
Published: December 2010

Abstract
Guidelines on the development of a successful test plan for large‐scale, aerospace vehicle shell buckling tests with particular attention given to defining test objectives and requirements are presented. In addition, some of the more challenging aspects of test planning, test operations, test article, and test apparatus design are discussed, and recommendations on instrumentation and control system setup for buckling tests and including state‐of‐the‐art measurement approaches and technologies are provided. In many cases, actual examples are given. This chapter is intended to provide the first time as well as the experienced test engineer or project manager with experiences and lessons learned from recent large‐scale aerospace vehicle development test activities at NASA.
Techniques for Damage Tolerance and Structural Integrity of Composite Structures
Authors: Razi Hamid , Ambur Damodar R. 
Published: December 2010

AbstractThis section discusses the importance of damage tolerance and how different damage conditions are addressed in the structural design process to assure structural integrity and safety of composite aircraft structures. The regulatory requirements from the Federal Aviation Regulations (FAR) and Joint Aviation Regulations (JAR) for damage‐tolerant design of aircraft structures are presented. Analysis and testing methods used for validation and certification are also summarized.
Future Aircraft Structures: From Metal to Composite Structures
Authors: Beukers Adriaan , Bersee Harald E.N. , Bergsma Otto , Koussios Sotiris , van Tooren Michel 
Published: December 2010

Abstract
In the twentieth century mobility became an important part of life. Aircraft and cars have evolved for over 70 years, and the conventional solutions for further improvements are reaching the point of saturation. Since the fifties, aircraft efficiency improvements were mainly based on refinements in aerodynamics (15 %) and propulsion (40 %). Structures on the other hand (concepts, materials, and manufacturing techniques), did not change all that much and relative weight reductions were annulled by comfort, safety and more systems. Even the latest developments in tools for analysis and design did not result in structure weight reduction, which might be an indication that a leap to novel materials and manufacturing techniques, a leap to new technologies, is the only way to achieve the necessary improvements. In this chapter composite materials are presented as a solution to not only reduce structural weight, to a maximum of 12 percent operational empty weight, but also to reduce exploitation costs and emissions for a 30‐year life span. Even though, by today's pricing, fiber reinforced polymers are more expensive per kilogram than most metals, on a life time basis, operational cost can be reduced by a decrease in fuel consumption, maintenance and inspection costs and, last but not least, manufacturing cost, which leads to long term cost savings. Therefore an integral approach for structure development is discussed, from concepts and materials to downstream manufacturing techniques. The emphasis is on structure and material simplicity and, on the reduction of the number of production steps from suppliers to final construction.
Advanced Composites Made by the Layer‐by‐Layer (
LBL
) Assembly of Nanomaterials
Authors: Podsiadlo Paul , Shim Bong Sup , Mamedov Arif A. , Kotov Nicholas A. 
Published: December 2010

Abstract
This chapter focuses on the preparation and applications of layer‐by‐layer (LBL) assembled organic/inorganic films. As model systems we use incorporation of two multifunctional nanomaterials in the LBL: the clay nanosheets and carbon nanotubes. All the aspects of the composite design starting with the structure of the individual nanoscale building blocks and their interactions with polymer matrix, orientation of the inorganic components in the multilayer, origin of record properties, and most likely applications of the resulting materials are given. Special attention is placed on the understanding of the control parameters for key functional properties such as mechanical strength/stiffness/toughness, electrical transport, transparency, and some properties relevant for biological applications.
Titanium Alloys: Processing, Properties, and Applications
Authors: Williams James C. 
Published: December 2010

AbstractThis chapter describes the history of titanium alloy development and production. It also summarizes the current range of applications for aerospace applications. The production of titanium alloys including processing to impart desired, application‐specific properties also is described. The ability to tailor the properties of titanium alloys by processing makes them attractive for a wide range of applications. The matching of properties to requirements is also discussed. Examples of applications are also described including the rationale for selecting titanium alloys even though the initial cost is higher.
Thermal Barrier Coatings
Authors: Paul Shiladitya 
Published: December 2010

Abstract
Modern gas turbine engines, both aircraft and industrial, operate under conditions of high temperature and stresses, and the engine components are also subjected to corrosion, oxidation, and abrasion. The ever‐increasing demand of higher operating temperature for better efficiency has led to researchers being on a constant lookout for new materials. The present operating temperature of gas turbine engines is limited by the onset of melting, creep, or excessive oxidation of the structural parts. Thermal barrier coatings (TBCs), which comprise oxidation‐resistant metallic and insulating ceramic layers, when deposited onto the hot sections of turbine engines improve their durability and efficiency. It is thus recognized that better understanding of TBC materials and their failure mechanisms must be gained to fully exploit the significant performance improvements they can offer.
In this short review, a description is given of the materials' issues involved in the development of TBCs together with a brief overview of the current TBC systems, their anatomy, failure mechanisms, and possible future progress.
Lifing Approaches and Component Classification: Overview of Methods
Authors: Brooks Jeffery W. , Tranter Paul H. 
Published: December 2010

Abstract
The modern gas turbine aeroengine is made up from many parts and these are divided into different categories relating to the safety of the engine and the aircraft to which the engines are fitted. These classifications vary between military and civil applications but the aim of operating an engine “safely” is similar. The drive to lighter and more efficient gas turbines has required advances in many areas, including materials, design methods, and manufacturing processes. These have shown up potential weaknesses in the traditional lifing approach and required new methodologies to be developed, so that the desired safety level is maintained.
Ferroelectric Materials
Authors: Landis Chad M. , Sirohi Jayant 
Published: December 2010

Abstract
Ferroelectrics are a class of materials that possess a spontaneous electrical dipole moment that can be reoriented with the application of a suitable electric field. Perhaps the most significant applications of ferroelectric materials are for sensors and actuators where the electromechanically coupled piezoelectric properties are utilized. However, ferroelectric materials have many other interesting physical behaviors including temperature‐induced phase changes, nonlinear dielectric, and ferroelastic behaviors. This chapter describes the fundamental thermal, electrical, and mechanical behaviors of ferroelectric ceramics. The discussion of these properties attempts to impart some physical intuition of the behaviors by referring to the underlying atomic structure of the material.
Introduction to Aerial Vehicle Flight Mechanics, Stability and Control
Authors: Knowles Kevin 
Published: December 2010

AbstractThis chapter provides an introduction to Volume 5, Part 22. It introduces some basic concepts of flight control, and static and dynamic stability. Some particular features of vertical or short take‐off and landing (V/STOL) aircraft flight control, not covered elsewhere in this part, are discussed briefly. The other chapters in this part are introduced.
Climb and Descent of Fixed‐Wing Aircraft
Authors: Young Trevor M. 
Published: December 2010

AbstractMethods are presented for the analysis of the climb and descent of fixed‐wing airplanes. The airplane has been treated as a rigid body, and classical techniques applicable to the dynamics of bodies in motion used. General equations are developed for an accelerated flight condition, where the associated unbalanced forces would cause the airplane's speed to either increase or decrease. A simplified flight condition, in which the airplane is assumed to be in a steady state (i.e., equilibrium), has been considered by setting the acceleration factor equal to zero. Expressions for the airplane's angle of climb/descent and for the rate of climb/descent are derived. The adopted approach initially considers flight in still air, and thereafter considers the impact of wind on the airplane's trajectory. A generic climb‐speed schedule, typical of that used by airliners, is presented as an illustration of an accelerated climb. The optimum speeds that would maximize the angle of climb or the rate of climb for jet and piston‐propeller airplane types are explored through the derivation of analytical expressions. A brief discussion on a topic related to climb performance, that is, the airplane's ceiling (i.e., maximum altitude), is included in the chapter.
Static Longitudinal Stability
Authors: Filippone Antonio 
Published: December 2010

Abstract
This chapter deals with the static longitudinal stability of fixed‐wing aircraft having a conventional configuration consisting of a wing and a horizontal tailplane with elevator and trim tab. The aircraft is considered as a rigid body. We provide a definition for the mean aerodynamic chord and show its role in the longitudinal stability problem. Then the pitching moment equations are written for the wing alone and the full aircraft. Trim equations are derived for stick‐fixed and stick‐free conditions; the corresponding stability points are calculated. Finally, the pull‐up up maneuver is described under steady‐state conditions; stick‐free and stick‐fixed maneuver points are derived.
Solar Sail Dynamics and Control
Authors: Dachwald Bernd 
Published: December 2010

AbstractSolar sails are large and lightweight reflective structures that are propelled by solar radiation pressure. This chapter covers their orbital and attitude dynamics and control. First, the advantages and limitations of solar sails are discussed and their history and development status is outlined. Because the dynamics of solar sails is governed by the (thermo‐)optical properties of the sail film, the basic solar radiation pressure force models have to be described and compared before parameters to measure solar sail performance can be defined. The next part covers the orbital dynamics of solar sails for heliocentric motion, planetocentric motion, and motion at Lagrangian equilibrium points. Afterwards, some advanced solar radiation pressure force models are described, which allow to quantify the thrust force on solar sails of arbitrary shape, the effects of temperature, of light incidence angle, of surface roughness, and the effects of optical degradation of the sail film in the space environment. The orbital motion of a solar sail is strongly coupled to its rotational motion, so that the attitude control of these soft and flexible structures is very challenging, especially for planetocentric orbits that require fast attitude maneuvers. Finally, some potential attitude control methods are sketched and selection criteria are given.
Satellite in Formation Flight
Authors: Alfriend Kyle T. 
Published: December 2010

AbstractThe fundamental aspects of the dynamics, control, and relative navigation of satellite formations are discussed. Types of relative motion orbits about a circular reference orbit and a spherical Earth are developed first and then expanded to relative motion about an eccentric reference orbit. The effects of gravitational perturbations on the formation dynamics are then presented along with some approaches for minimizing their effects. This is followed by a short discussion of control for the establishment, maintenance and reconfiguration of formations. A discussion of relative navigation for formations is then presented.