bluuebunny/crossref_metadata_2025 huggingface dataset:
Textile Composite Materials: Polymer Matrix Composites
Authors: Lomov Stepan V. , Verpoest Ignaas
Published: December 2010

The chapter presents an overview of composites reinforced with woven, braided, non‐crimp fabrics (NCFs). Starting with classification of the reinforcements, it discusses their behavior during composite manufacturing (formability and permeability) and internal architecture of the reinforcement. The latter determines mechanical behavior of textile composites. Formulae for calculation of composite stiffness are presented, followed by discussion of strength and damage development in textile composites. Finally, the modeling tools for textile composites are reviewed.
Textile Composite Materials: Ceramic Matrix Composites
Authors: Marshall David , Cox Brian
Published: December 2010

The last decade has seen the maturation of textile methods for making ceramic matrix composites with three‐dimensional (3D) fiber‐reinforcement. Such composites are much less vulnerable than traditional two‐dimensional (2D) ceramic composites to premature brittle failure, especially via delamination. Innovative textile methods also enable the creation of complex features that are formed integrally in a component as local rearrangements of the reinforcement. They also allow design of optimal fiber architectures for individual components to match the thermal and mechanical loads expected in use. This chapter begins with an introduction to conventional 2D laminate ceramic composites, including discussion of approaches that have been taken to achieve damage tolerance, the materials available for fibers, matrices, and coatings, and the rationale for selection of different materials for specific aerospace components. Several examples are then discussed of textile‐based composite components with 3D reinforcement architectures that have been developed for turbine, rocket, and scramjet applications. Some of the complexities of dealing with modeling/life prediction in these materials are discussed, along with some of the approaches for dealing with them.
3D Translaminar and Textile Reinforcements for Composites
Authors: Bogdanovich Alexander E.
Published: December 2010

The group of translaminar‐reinforced composites, which includes stitched and Z‐pinned materials, requires additional manufacturing step (insertion of a stitch thread or Z‐pin) after the in‐plane fiber architecture has been already formed. This is why this group suffers from in‐plane fiber damage, distortions of the fiber architecture and the formation of resin‐rich zones in the vicinity of each stitch or Z‐pin. These negative effects may considerably reduce in‐plane elastic moduli but most significantly reduce in‐plane tension and compression strengths and fatigue resistance. The group of unitary (single‐ply) 3D textile reinforcements includes 3D weaves, 3D braids and 3D warp knits. The principal common feature of all preforms from this group is, that each of them is produced in a single manufacturing step, using either traditional or specialty textile machines. Owed to this feature, unitary 3D textile preforms can be used in a composite fabrication process as‐manufactured, thus greatly simplifying preform handling and resin infusion steps. Comparative analysis of various methods of 3D reinforcement for composites shows that the differences in the processes and machines strongly influence the differences in the reinforcement architectures and, consequently, strongly reflect on mechanical properties of the resulting composites. This is illustrated by experimental data on the in‐plane and out‐of‐plane mechanical properties of 2D weave laminates and composites reinforced with a single‐ply of 3D interlock weave or 3D orthogonal non‐crimp weave.
Lasers in Aerospace Industry Manufacturing
Authors: Mazumder Jyoti
Published: December 2010

The Aerospace Industry has adopted laser technology from its early days and several laser‐aided manufacturing processes have become routine. Lasers can deliver energy from zero to a trillion watts in a small spot in an instant. That generated a wide portfolio. For example, laser peening needs more than 10
9
W cm
−2
, whereas laser welding can be accomplished with 10
6
W cm
−2
; laser drilling requires 10
8
W cm
−2
compared to 10
5
W cm
−2
or more for laser cladding and solid free form formation. The mechanism for different processes is different although the energy source is common. Interaction time for each process is different, too. Laser shock peening utilizes nanosecond pulses compared to millisecond pulses for drilling. Welding and cladding are generally carried out with continuous wave. The role they play is also varied. Drilling generates cooling holes for turbine blades to enhance the operating temperature whereas shot peening produces residual compressive stress on the blades to improve fatigue properties and reduce crack propagation. Welding is mostly used to join structural components whereas cladding repair of reconfigured aerospace components is used to increase their service life. This chapter will discuss the four most common uses of lasers in Aerospace Industry Manufacturing.
Near Net Shape Forming of Aeroengine Components
Authors: Wu Xinhua
Published: December 2010

This chapter is aimed at providing a brief overview of near net shape forming of aeroengine components. Among many near net shape‐forming processes, this chapter will focus on direct laser deposition (DLD) and net shape HIPping (NSHIPping). DLD has applications in the area of building small components or for precision repair, and NSHIPping is mainly used for manufacturing large components, especially from Ti or Ni alloys. The chapter will cover an introduction to these technologies, their pros and cons, the mechanical properties of the components manufactured using these processes, and the issues for their application in the aerospace industry.
Piezoceramic Actuators and Sensors
Authors: Sirohi Jayant , Chopra Inderjit
Published: December 2010

Piezoceramic actuators and sensors have found wide application in a variety of fields such as aerospace, automotive and biomedical. The coupled electro‐mechanical behavior exhibited by these materials enables them to be used either as actuators or as sensors. The material has a high bandwidth, can be manufactured in a number of different shapes, and can be easily integrated into structures. This chapter focuses on the behavior of piezoceramic actuators and sensors. The electro‐mechanical constitutive equations are discussed, and the static as well as dynamic response of the material to applied electric fields is described. Nonlinear phenomena are also described, and the power consumption of piezoceramic actuators is explained. The use of the material as a strain sensor is also described in detail, along with the required signal conditioning electronics and calibration factors. This information is intended to serve as a reference for the design of a structure incorporating piezoceramic materials.
Polymers in Space
Authors: Skurat Vladimir E.
Published: December 2010

Polymeric materials are widely used in space engineering because of the beneficial combination of their working properties. Being in harsh space environment conditions, mainly in the form of thin films, they are subjected to the action of numerous destructive factors that are absent during their exploitation on Earth. Most serious problems are connected with changes of thermo optical properties, deterioration of mechanical properties, production of components of the intrinsic outer atmosphere of spacecraft that respond to contamination of its surface, and last but not least, mass losses. Here, the main focus is on polymers of two types that are generally used in multilayer insulation (MLI) of spacecraft as thin films – polyimide Kapton H and perfluorocarbon polymers – polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP). Both types of polymers show mass losses, but they are caused by different factors. For Kapton H, it is fast atomic oxygen (FAO) on low Earth orbits (LEO) (altitudes 200–1000 km). For PTFE and FEP, it is mainly the vacuum ultraviolet (VUV) component of solar radiation (wavelengths 1–200 nm) (all altitudes for space flights). Possible mechanisms of mass losses are considered.
Micrometeoroid and Orbital Debris Impact Damage on Materials and Structures in Space
Authors: Tennyson Roderick C.
Published: December 2010

The effect of hypervelocity impacts from micrometeoroids and orbital debris (MOD) on spacecraft materials and structures is discussed in terms of observed flight damage and laboratory simulation tests. Methods of estimating the probability of impact as a function of particle size are presented based on particle distributions and orbital altitude. Two types of damage mechanisms are described: initial impact cratering, and debris plumes emanating from the impact site. Shielding systems currently employed are also described. With the return of human exploration of the moon, the effect of meteoroid impacts on lunar structures and equipment is also examined.
Materials Spaceflight Experiments
Authors: de Groh Kim K.
Published: December 2010

Space environmental effects on spacecraft materials can be severe due to individual and synergistic interactions of orbital environments such as solar ultraviolet radiation, charged particle radiation, temperature extremes and thermal cycling, impacts from micrometeoroids and orbital debris, environment induced contamination, and low Earth orbital atomic oxygen. Space environmental threats vary greatly based on spacecraft materials, thicknesses and stress levels, and the mission environment and duration. Materials spaceflight experiments have been conducted since the early 1970s to help understand the effects of the space environment on spacecraft materials, components and devices. Materials experiments have been flown on Skylab, Salyut and Mir, the space shuttle, and the International Space Station. In addition, there have been free‐flyer experiments such as the Long Duration Exposure Facility. In addition to being critical for understanding the engineering performance of materials exposed to specific space environments, data from spaceflight experiments can be used to determine correlations between exposures in ground‐test facilities and space, thus allowing more accurate in‐space materials performance predictions to be made based on ground‐facility testing. This chapter reviews most major materials spaceflight experiments along with some of the lessons learned from the experiments, and how the results have influenced materials use and selection.
Maneuver Performance of Fixed‐Wing Transport Aircraft
Authors: Young Trevor M.
Published: December 2010

Maneuver performance of fixed‐wing transport airplanes is discussed and methods for the analysis of the airplane during turning and pitching maneuvers is presented. General equations are developed for the analysis of the airplane in a level turn, and the factors that can limit the airplane's turn rate are discussed (e.g., available thrust, structural limits and maximum lift coefficient). The angle of attack limit for an airplane is associated with the stall condition, which depends on several factors, such as airplane configuration, weight, load factor and thrust setting. Several safety‐critical operational speeds are defined as a fixed multiple of the stall speed. For this purpose, a 1‐greference stall speed is defined. Whereas the stall condition sets a lower speed limit for the airplane, high speed buffet, which is a function of altitude, sets an upper speed limit. TheV–ndiagram, which depicts the airplane's limit load factor as a function of equivalent airspeed, provides engineers with the basis for determining the structural design loads, and it provides the limits within which the airplane can be safely operated. An outline of the methods used to construct aV–ndiagram, as described in the airworthiness regulations, is presented.
Maneuver of Fixed‐Wing Combat Aircraft
Authors: Render Peter M.
Published: December 2010

The importance of energy and specific excess power in assessing the maneuverability of combat aircraft is discussed. This is followed by a discussion on climb and turn performance, which extends the methods presented in other sections. In particular, high angle climbs and the climbing turn are considered. The use of performance metrics to assess aircraft performance is described, and both traditional (e.g., specific excess power plots) and new metrics (e.g., combat cycle time) are described. The article concludes by considering features which have been adopted on the latest combat aircraft, namely relaxed stability, the canard configuration and thrust vectoring.
Rotary‐Wing Static Stability
Authors: Lee David A.
Published: December 2010

The static stability of a rotary‐wing aircraft is established by observing its immediate response following a disturbance from a trimmed flight condition. For a helicopter, this can include rearwards, sideways, forwards, and hovering trimmed flight at constant altitude or in a climb or descent. The disturbance response of the main rotor dominates the helicopter response. Modeling this response is crucial in the development of stability and control derivative data to predict static and maneuver stabilities, the latter term describing a form of static stability where response to variations in angle of attack is assessed. Notwithstanding the complexities of the rotor system modeling, the flight‐testing techniques for static and maneuver stabilities from the pilot's perspective of the cockpit inceptor positions and applied forces are straightforward. The results from these flight tests for static stability contribute significantly to the overall assessment of an aircraft's stability, control, and response characteristics. However, the final assessment must include results from other dynamic stability and control response evaluations and from assigned handling quality ratings (HQRs) awarded by test pilots on completion of carefully planned handling tasks.
Aircraft Navigation
Authors: Hagström Martin , Lennartsson Anders
Published: December 2010

Navigation is an essential part of flying where crew keep track of the position of a moving aircraft relative to the Earth. Early in aviation history the tools for this were maps, compass, airspeed, indicator, clock, and astronavigation. Modern systems in the craft, on the ground and in space, have to a large degree automated this task and provides high accuracy and availability. There are now ground based navigation systems with area coverage, specialized systems for landing procedures, radio beacons, distance measuring equipment, radar and transponders, inertial navigation systems, and satellite navigation receivers. Equally important as these technical aids are air traffic control, maps, and procedures. Today the art of air navigation involves a working knowledge of all these systems.
Guided Weapon andUAVNavigation and Path‐Planning
Authors: Faruqi Farhan A.
Published: December 2010

In this chapter, techniques and technologies used for weapon, unmanned air vehicles (UAV), and aircraft navigation and guidance are described and the basic principles of analysis and synthesis of the techniques are established. Problems associated with inertial navigation system (INS), global positioning system (GPS) for missiles and UAV are discussed including methods for deriving navigation information from GPS, INS, and integrated GPS/INS. The application and principles of terrain reference navigation (TRN) systems such as terrain profile matching (TERPROM), terrain contour matching (TERCOM), and terrain scene matching (TERSMAC) are described and methods for combining these techniques with other navigation systems using the Kalman filter are discussed. Aircraft and UAV path planning is considered and a method for generating an optimum path to achieve a stealthy mission through an enemy territory is described. Guided weapon autonomous guidance strategies commonly used today such as the command to line of sight (CLOS) and proportional navigation (PN) guidance are described. Methods for analysis and synthesis of these guidance techniques are established and their performance discussed. Different guidance phases of weapons during target engagements are discussed and the various guidance modes (active, semi‐active, and passive) are described.
Adaptive and Robust Flight Control
Authors: Wise Kevin A.
Published: December 2010

This chapter presents the theory and application of model reference adaptive control (MRAC) to augment a baseline control to improve performance and robustness to model uncertainties. The adaptive control is derived using a Lyapunov‐type argument and is shown to extend performance and robustness of a baseline linear quadratic regulator control law. A flight control application is used to demonstrate the approach and evaluate the design using nonlinear simulation.
Cooperative Control for Multiple Air Vehicles
Authors: Schumacher Corey J.
Published: December 2010

This chapter provides an overview of topics, technical challenges, and methods involved in cooperative control for multiple air vehicles. This is a broad area, with many subtopics and technical disciplines potentially involved. Subtopics of cooperative control include: cooperative motion and formation control, cooperative search and area coverage, task assignment and scheduling, and cooperative task execution. The particular technical challenges involved can vary depending on the exact type of cooperative control problem discussed, but certain difficulties are ubiquitous, particularly uncertainty, limited communication, and task coupling. This discussion focuses on technical challenges and solution methods related to assignment and scheduling problems for cooperative teams.
Integrated Health Monitoring for Multiple Air Vehicles
Authors: Léchevin Nicolas , Rabbath Camille A. , Su Chun‐Yi
Published: December 2010

This chapter proposes an integrated health monitoring system whose objective is to maintain the integrity of a fleet of small unmanned aerial vehicles, or UAVs, despite the occurrence of actuator faults and body damage. The monitoring system relies on distributed, team‐level abrupt and nonabrupt fault detectors (NaFDs) and enables UAV teams to compensate for an ineffective individual vehicle fault detection and recovery system, if any. The abrupt and nonabrupt fault detectors utilize relative positions and speeds of vehicles within sensor range, in addition to exploiting information available through the communication network. A special attention is given to the selection of the detector thresholds, at the design phase, to minimize the average time of detection and the probability of missed detections, while constraining the probability of false alarms to an acceptable limit. For such purpose, an automated procedure based on stochastic search is proposed. Integrated health monitoring and control is demonstrated numerically by means of high‐fidelity, nonlinear 6‐degree‐of‐freedom (6‐DOF) simulations of teaming small‐scale UAVs. The chapter shows that concurrent nonabrupt and abrupt faults can be detected and effectively compensated for, thus preserving the integrity of a formation.
Radar Waveforms and Signal Processing
Authors: Levanon Nadav
Published: December 2010

The waveform determines the delay‐Doppler response of a radar system, hence the radar's range and velocity resolution and ambiguities. This chapter shows how narrow‐band signals are described and presents the major signal processing and analysis tools – the matched filter (MF) and the ambiguity function (AF). Basic signals that are discussed are unmodulated rectangular pulse, linear frequency modulated (FM) pulse compression, binary and polyphase‐coded signals, and a coherent pulse train. Additional topics are sidelobe reduction and periodic continuous waveforms.
Automatic target recognition
Authors: Mishra Amit K. , Mulgrew Bernard
Published: December 2010

One of the important forms of military intelligence consists of recognizing the type of target in the battle field. If good‐quality optical image of the battle scene is available, target recognition is done mostly by human experts. However, for sensors like infrared sensors and radars, target recognition solely by human experts is difficult. Hence, application of pattern recognition techniques, mainly in systems based on sensors like these, is prevalent and is known as automatic target recognition (ATR). This chapter will start with a short description of ATR and the challenges involved. Radar‐based ATR, especially synthetic aperture radar (SAR)‐based ATR, is one of the most popular ATR schemes, and hence the rest of the chapter will be devoted to SAR ATR. We will first describe the different stages of a generic ATR system and then elaborate some of the major challenges of radar‐based ATR. This will be followed by a description about the major figures of merit for a SAR ATR algorithm. The chapter will discuss some of the important algorithms from the open literature dealing with radar‐based ATR. We will also discuss some of the recent developments in the field of ATR, for example, bistatic radar‐based ATR, polarimetric radar‐based ATR, and multi‐look radar‐based ATR. The chapter will close with a note on the futuristic radar‐based ATR systems.
Electro‐Optic Imaging and Tracking Systems
Authors: Richardson Mark A. , James David B.
Published: December 2010

In Electro‐optic Sensor Principles the origins of a targets electro‐magnetic signature and the nature of lasers and their operation are presented and discussed. In this chapter the nature of electro‐optic (EO) imaging and tracking systems will be presented and the common applications of laser systems. The evolution and functioning of missile seekers will also be discussed. Since its development in the 1960s the laser has fulfilled many novel roles within both civil and military environments. This chapter will also present the principles of the most common laser applications, such as laser rangefinding and LIDAR, as well as laser target designation. In addition the role of the laser as a potential weapon to cause dazzle and damage to EO sensors will be discussed. Finally, the role of lasers in retro‐reflection detection for counter surveillance will be presented.
Interplanetary Navigation
Authors: Wood Lincoln J.
Published: December 2010

The navigation of interplanetary spacecraft is a complex, multi‐faceted process, with measurement acquisition, flight path estimation, and flight path control as its major constituents. Radio metric data, derived from the spacecraft‐to‐ground communication link, yield information about spacecraft position and velocity and other parameters of interest. Optical data, derived from on‐board imaging systems, yield target‐relative navigational information. Sophisticated computational techniques are used to accurately estimate spacecraft position and velocity and other quantities of interest that affect the spacecraft's motion and the measurement values.
Satellite Orbit Determination
Authors: Born George H. , Jones Brandon A.
Published: December 2010

Modern orbit determination methodology dates back to the beginning of the nineteenth century, when Legendre attempted to determine the orbits of the planets. Both he and Gauss recognized the importance of observational errors and proposed the least‐squares solution as a method for minimizing the effect of such errors. Over the past four decades the accuracy of determining Earth orbiter positions has evolved from hundreds of meters to a few centimeters. This chapter provides an overview of the history of satellite orbit determination and a review of the numerical algorithms needed for a basic orbit determination software system.
Libration Point Orbits and the Three‐Body Problem
Authors: Davis Kathryn , Anderson Rodney L.
Published: December 2010

Libration point orbits in the three‐body problem play an important role in mission design. Their size, shape, location, and dynamical features are attractive for many different science and exploration missions, with objectives ranging from the collection of solar observations and measurements, to a search for the first massive black holes, to the direct imaging of planets within the habitable zone of stars beyond our solar system. The gravitational forces of two massive bodies govern the dynamics in the vicinity of the libration points and the motion in this regime is vastly different from traditional Keplerian motion. This chapter presents a historical overview of the three‐body problem, its formulation and assumptions, and the corresponding equations of motion. Methods of analytically and numerically computing libration point orbits are presented, along with a discussion on orbit stability. Invariant manifolds, trajectories that asymptotically approach or depart a nominal orbit, are described, as is their application for constructing transfers between orbits. Additionally, a brief survey of past, future, and proposed libration point orbit missions is presented.
Fault Detection, Isolation, and Recovery of Guidance, Navigation and Control
Authors: Chen George , Burt J. Brad
Published: December 2010

The subject of spacecraft fault detection, isolation, and recovery, also known as fault protection, is introduced along with standard terminology. A general description of a typical fault protection system is presented with a specific emphasis on the application to guidance, navigation, and control (GN&C) subsystems. The functions of a fault protection system for a notional three‐axis controlled GN&C subsystem are presented as examples. Finally, the role of various types of redundancy and the desire for graceful degradation in the presence of failures in fault protection systems are discussed.
Close Proximity Rendezvous and Docking (RVD)
Authors: Fehse Wigbert
Published: December 2010

Rendezvous and docking (RVD) techniques are required in most of the space operations, which involve more than one spacecraft. This chapter describes the basic tasks, the scenarios, and the phases of a rendezvous mission. Since the first phases are not much different from other space missions, the chapter concentrates on the rendezvous phases with relative navigation. Typical rendezvous trajectories and strategies are shown. Onboard control systems and relative navigation sensors for automatic RVD in low earth orbit (LEO) are described. The principle of docking and berthing is addressed also and types of docking mechanism are discussed. The chapter addresses the differences between LEO of rendezvous operations in other orbits and the role of human operators in various rendezvous scenarios.
Atmospheric Composition
Authors: Schlatter Thomas W.
Published: December 2010

This chapter considers the gases constituting Earth's atmosphere and how the mixture of atmospheric gases varies with altitude up to roughly 1000 km. Turbulent mixing keeps the relative concentrations of gases nearly constant in the lowest 100 km. At higher altitudes, molecular diffusion controls the concentrations, with the lighter gases becoming relatively more abundant with increasing altitude. Atmospheric gases are electrically neutral up to about 60‐km altitude. At higher altitudes, energetic solar radiation from the sun ionizes neutral molecules, creating charged particles (ions and free electrons), which mix with the neutral particles.
The Earth's Magnetic Field
Authors: Macmillan Susan , Rycroft Michael J.
Published: December 2010

The Earth's magnetic field is generated in the fluid region deep inside the Earth. Heat convection, buoyancy forces, and planetary rotation cause the iron‐rich fluid in the outer core to flow in a complex way and the movement of this electrical conductor through existing magnetic field generates electrical current. This produces more magnetic field in an advective process. Some of it diffuses away resulting in a reasonably stable magnetic field, which is broadly dipolar outside the planet and which occasionally reverses its polarity. Parameters of the Earth's magnetic field observed near the surface of the planet vary in space and time over wide ranges. As well as processes acting in the deep interior of Earth, the crust, the ionosphere, the magnetosphere, and the Sun all contribute to the observed magnetic field. Indeed, the magnetosphere is formed by the interaction of the solar wind, moving radially outwards from the Sun at supersonic speeds, with the Earth's magnetic field (see also The Plasma and Radiation Environment in Earth Orbit). Geomagnetic observations are made at fixed sites at observatories, and extensive surveys are carried out on land, at sea, and from aircraft and satellites; the magnetic properties of rocks provide further information. The Earth's magnetic field is important for many aerospace applications today, and these areas are especially considered.
Micrometeoroids
Authors: Srama Ralf
Published: December 2010

Micrometeoroids are natural dust particles with masses between 10
−21
and 10
−9
kg (0.01–100 μm). In contrast to space debris, their sources are bodies in the solar system like comets, asteroids or planetary environments.

Although comets are the most obvious source of interplanetary dust in the inner solar system, there exist a variety of dusty phenomena and dust sources.

An recent summary about interplanetary dust was given by gruen 2001. Our current knowledge is based on remote sensing observations (light scattering, thermal emissions),
in‐situ
dust experiments, (Pioneer, Giotto, Helios, Heos, Nozomi, Gorid, Galileo, Cassini, Ulysses, Stardust, New Horizon), crater studies of moon rocks or of planetary moon surfaces, meteor radar studies and laboratory sample analysis. (dust extracted from polar ices, dust collected in the stratosphere, dust returned by Stardust, dust and space debris impact residues of returned satellite parts).

The following sections describe the measurement techniques of micrometeoroids, the properties of interplanetary dust (mass flux, dynamics, or composition) and the dust sources like comets, asteroids, or planetary environments. Two later sections give examples of laboratory simulation facilities. Finally, hazards related to hyper‐velocity micrometeoroid impacts are discussed.
Propulsion System Noise: Turbomachinery
Authors: Astley R. Jeremy
Published: December 2010

Turbomachinery sources are important contributors to whole aircraft noise both at takeoff and approach. The turbomachinery contribution contains both tone and broadband components and is generated by a variety of mechanisms that occur in the fan, turbine, compressor, and combustor. These different sources are reviewed along with technologies that have been developed to mitigate their effect, either by reducing noise at source or by applying sound‐absorbing treatments within the engine. Discussion is limited here to the exterior impact of turbofan noise on communities near airports. The effect on passengers and crew within the aircraft is dealt with separately elsewhere. Attempts to mitigate the environmental impact of aircraft noise are dominated by the metrics that are used to certify and regulate aircraft noise. These are introduced and their implications are discussed.
Interior Noise and Sound Transmission
Authors: Neple Pascale
Published: December 2010

Aircraft interior noise control as a major factor of cabin and cockpit comfort is considered as an essential design requirement by transport airplane manufacturers. External sources such as the turbulent boundary layer excitation and acoustic radiation from engines being the main interior noise contributors over a large frequency range, this section focuses mainly on sound transmission through fuselage structure and noise control treatments. After describing the existing noise sources and the main characteristics of a fuselage structure including classical noise control treatments, the emphasis will be put on the methodology to assess interior noise, based on typical testing and existing modeling methods. The complexity of the fluid‐structure coupled issue and the main weak and strong points of each modeling method, both at aircraft and fuselage element level, will be addressed. Then, understanding and modeling the vibroacoustic behavior of stiffened structures being necessary to assess overall interior noise level, a dedicated section will describe the main phenomena governing sound transmission through these elements. Finally, the excitation field effect on sound transmission mechanisms and particularly on noise control treatments efficiency will be discussed. Turbulent boundary layer, diffuse sound field, and structure‐borne excitation will be considered.
Sonic Boom
Authors: Sparrow Victor W.
Published: December 2010

Supersonic flight is always accompanied by shock waves that may be heard as a sonic boom. This chapter provides a brief overview of sonic booms, including their generation, propagation, and resultant noise at ground level. For current and past supersonic aircraft the loudness of the sonic boom has led to stringent restrictions on civil overland supersonic flight. Recent research in aerospace engineering and related areas has opened the possibility for supersonic flight with sonic booms of a reduced loudness that may be acceptable to the public. This chapter will also provide a summary of the existing challenges for developing acceptable low‐boom aircraft designs and recent successful attempts toward boom minimization.
Chemistry of the Atmosphere and Impacts from Global Aviation
Authors: Köhler Marcus O.
Published: December 2010

A variety of chemical processes take place between the chemical trace constituents contained in air. These processes form an important part of the natural global biogeochemical cycles. Anthropogenic emissions of chemically active pollutants can interfere in the natural chemical processes and result in impacts on the climate system or lead to the accumulation of substances hazardous to ecosystems. This chapter outlines the most important chemical processes taking place in the atmosphere with a view to the global scale and to an extent as they are of relevance to chemical interference caused by aircraft engine emissions. The effects caused by emissions of nitrogen oxides, sulfur compounds, and water vapor from subsonic aviation are discussed and placed in context with global atmospheric chemistry.
Aviation Emissions
Authors: Owen Bethan , Lee David S.
Published: December 2010

Aviation exerts effects on climate change through CO
2
emissions and its non‐CO
2
emissions and effects. The most up to date aviation kerosene sales from International Energy Agency data were 241.3 Tg in 2007, that is, 761 Tg of CO
2
. The latest global CO
2
emissions data from the US Carbon Dioxide Information Center for all sources (fossil fuel, cement manufacturing, and gas flaring) indicate emissions of 30 177 Tg CO
2
in 2006, such that aviation represented 2.5% of these emissions in 2006. Long‐term average global air traffic in revenue passenger kilometres (RPK) and its CO
2
emissions have steadily increased since 1970 to 2007 at 6.25% and 2.74% per year. The current global economic crises affected aviation in the second half of 2008 such that traffic only increased by 1.3% from 2007 to 2008 (contrasting with 7.3% RPK from 2006 to 2007). Recently developed aviation emissions scenarios to 2050 imply increase over 2000 emission rates by factors ranging between 2 and 3.6.
Space Debris Impact Protection
Authors: Stokes Hedley
Published: December 2010

Protection against impacts from space debris and meteoroids is now routine in the design of manned spacecraft, and is becoming increasingly so for unmanned spacecraft. Commonly considered solutions for improving protection include: the addition of multibumper shields; the modification of sandwich panels; the enhancement of multilayer insulation; and the use of toughened/laminated glass. A brief summary of each of these concepts is provided. Layers of high‐strength, lightweight materials, such as Nextel™ and Kevlar™, are observed to be particularly effective forms of shielding. The ability of a spacecraft wall or shield to prevent debris penetration is usually characterized by a ballistic limit equation. A parametric form of the equation is given for both a single wall and a multiple wall. Such equations are an important element of an impact risk analysis, providing a means to determine the probability of no failure of a spacecraft. This measure of risk enables a designer to quantify the adequacy of a given protection strategy for a spacecraft. The risk analysis computation is explained and a risk assessment procedure is given. Finally, some general guidelines for enhancing spacecraft debris protection are listed.
Composite Aerospace Manufacturing Processes
Authors: Bersee Harald E.N.
Published: December 2010

The development of glass fibers, in the beginning of the 1950s, and boron fibers, in the beginning of the 1960s, and new resins like epoxy and polyester gave a lot of impulses to the research of composite materials in aircraft structures. The development of high modulus carbon fibers has ultimately resulted in the increased composite usage of up to 50% in the new wide bodies of Airbus and Boeing. The driving force in using composite materials in aircraft structures is the potential of considerable weight savings. These weight savings are possible because of the high specific strength and stiffness of composite materials. The major drawback of composites is their higher manufacturing and material costs compared with metallic structures. Consequently, much of the research on composites is focused on the development of affordable composite materials and manufacturing techniques, which don't require an expensive autoclave. Another focus is on the development of manufacturing techniques, which can be automated as much as possible, for example, automatic tape laying, robotic fiber placement, resin transfer molding and rubber forming. An overview is given of the different types of fibers, resins, fiber arrangements, and manufacturing techniques as being used in the aerospace Industry.
Automated Aerospace Manufacture and Assembly
Authors: Webb Phil
Published: December 2010

The application of significant levels of automation within aerospace manufacturing is a hot topic and is likely to have a significant impact on the industry in the future. However there are still significant risks and unique problems associated with its implementation and there have been many previous applications which have not lived up to expectations. This chapter looks at some of the drivers and barriers involved in the application of automation as well as looking at the principle types of system and the applications in which they have been used. Whilst there is much excellent research in progress the chapter is biased towards actual production systems as these are more representative of the proven state of the art.
Lean Supply Chain Management in Aerospace
Authors: Beelaerts van Blokland Wouter W.A. , Santema S.C. , Curran R.
Published: December 2010

A recent trend in aerospace is that aircraft original equipment manufacturers (OEMs) such as Boeing, Airbus, Embraer, Eurocopter and for instance Dassault, are developing from a “production” orientated company towards “integrators of value.” Suppliers were already involved mainly with “built to print” activities, leaving most of the risk with the OEM. Today, the suppliers are involved with the co‐development of entire functions of the aircraft such as wings, fuselage, and stabilizers, which causes the production value to shift from the aerospace OEM towards the supply chain (SC) and network. The co‐development includes the investment in development for the specific aircraft function(s) by the suppliers. The aerospace OEM is in fact leveraging value on suppliers; this is what we call “value‐leverage.” The rational behind this value‐leverage approach is the reduction of supply complexity, which destines from lean manufacturing theories adopted from the automotive industry.

Examples of Boeing B787 and Eurocopter show the approach of value‐leverage on the suppliers. The 3C value‐leverage model is found as an applicable method to measure value‐leverage effects in a network, from which suppliers are most important value drivers. Aerospace OEM companies are challenged to leverage value smart on the supply chain and network to make value to flow.
Lean Product Introduction
Authors: Roy Rajat , James‐Moore Mike
Published: December 2010

This chapter discusses the challenges faced by the aerospace industry and the feasibility of applying lean principles, complexity management, and design for manufacture in the sector. It draws on work carried out as part of the UK Lean Aerospace Initiative Research Program, which ran in parallel to a similar US program based at MIT, and research at Warwick Manufacturing Group (WMG) for the premium automotive industry. It considers the new product introduction process, lean engineering metrics, and design for manufacture across an enterprise and suggests some approaches which can help in meeting the challenges. The chapter also considers the role of manufacturing in the aerospace industry and whether it is given sufficient importance. It concludes that the application of lean principles in business areas outside the traditional production processes, as well as design for manufacture and complexity management, can have very significant benefits but that much still need to be learnt regarding their effective application. It also concludes that a more dominant role for manufacturing should be considered at the design stage, and that the process of transfer from design to manufacture is immature in the sector.
Civil Transport Aircraft
Authors: Torenbeek Egbert , La Rocca Gianfranco
Published: December 2010

The chapter presents an overview of jet airliner evolution after the Second World War. It illustrates that modern airliner general arrangement is based on early concepts, namely the Boeing B‐47 bomber and the B‐707 airliner of the 1950s. The most significant economical and environmental improvements were achieved in gas turbine engine technology, culminating in the modern very efficient and reliable high‐bypass ratio turbofan. A concise geometrical description of the aircraft's main components is followed by a brief description of major technological breakthroughs over the past decades. Subjects treated are flight control, avionics, structural design, and materials. The continuously improving energy efficiency is illustrated by a data collection showing that the seat‐km per liter of gas turbine fuel produced by modern jet airliners exceeds the performance of mid‐sized cars, even though their cruising speed is an order of magnitude higher.
Military Airplanes
Authors: Tsach Shlomo , Tatievsky Alex , Kleiman Dan , London Lior
Published: December 2010

This chapter presents an overview and historical review of military aircraft. A military aircraft is defined as an aircraft that executes military missions. This is a wide definition and includes various airborne platforms. The main three platforms are fighters, bombers, and transports aircraft.

The potential of aircraft for military use was understood even prior to the first flight of a heavier‐than‐air airborne vehicle. In its development history throughout the last century, major military aviation developments were spurred by wars. World War I presented to the world the first massive use of military aviation as a combat and reconnaissance military branch. The Second World War already presented a developed concept of military aviation, including heavy use of fighter, bomber, and transport aircraft in military campaigns. As a result of these developments, major progress in the aeronautical fields has occurred. New jet propulsion, new avionics, and new materials have appeared and thousands of flight hours contributed to further understanding and development of military and civil aviation.

During the second half of the twentieth century, leading countries invested in developing new designs.

The most impressive progress was the jet fighter – new aeronautical innovations, achieved by technological advances in aerodynamics, propulsion, and avionics.
Rotary Wing Vehicles
Authors: Pavel Marilena D. , van Holten Theo
Published: December 2010

Rotary wing vehicles or rotorcraft may be defined as flying vehicles, which derive their lift from rotating wings. Within this class, helicopters are probably the most representatives for their characteristics. The present chapter gives a survey mainly on helicopter characteristics presenting their components and the principles of controlling. The chapter underlines the difficulties of vertical flight and the solutions developed to successfully achieve missions otherwise impossible to perform with fixed wing aircraft.
Conceptual Airplane Design Systems
Authors: Anemaat Willem A. J.
Published: December 2010

A historic overview is given of commercial and academic airplane design systems. The most common airplane design systems used nowadays are DARcorporation Advanced Aircraft Analysis, DaVinci Technologies AirplanePDQ, OAD aircraft design software (ADS), Raymer RDS, and Pacelab APD.

Aircraft conceptual and preliminary design systems are developed for the following benefits:

reduced design time, as computer‐aided design methods can reduce design and development time, and replace tedious hand calculations;

better product through improved design: more alternative designs can be evaluated in the same time span, which can lead to improved quality;

reduced design cost: less training and less calculation errors leads to substantial savings in design time and related cost; and

improved efficiency: the design engineer can avoid technically correct but irrelevant calculations on incomplete or out‐of‐sync information, particularly if the process enables robust geometry earlier.

A description of knowledge‐based design systems is given. Although numerous advancements in knowledge‐based design have been achieved, development of such integrated knowledge‐based conceptual and preliminary airplane design systems is still in its infancy.
Integrated Design Optimization
Authors: Soban Danielle , Price Mark
Published: December 2010

In the creation of engineering products and systems there is always a desire to make the finished article as good as it can be. The optimum solution is the goal. Moreover, it is the nature of innovation to seek continual improvement in everything. Engineers in particular attempt to optimize using mathematical tools to ensure that systems meet the many conflicting demands of their users. The complexity of modern engineering systems, such as aircraft, means that such optimization is a challenging task. Aircraft are designed to meet many competing requirements and the final vehicle design is always a compromise between the physics and economics of many disciplines. The design process itself is also complex, being hierarchical and iterative, as it attempts to facilitate so many disciplines. Aircraft design is a prime example of a multi‐objective, multi‐disciplinary problem which needs the most advanced tools and capabilities to achieve any solution. This chapter introduces some of the latest design approaches for aircraft which use optimization methods. These are necessarily adaptations of the mathematical methods and multi‐disciplinary design optimization (MDO) approaches (see Formulating Design Problems as Optimization Problems) but used in a manner suited to the integrated design environment appropriate for aircraft. These methods permit good solutions to be found, and even better can provide guidance for the designer on robust solutions, which not only achieve good performance at the target design point, but remains good when the environment and parameters change to less favorable values. Such robust designs can reduce risk and result in stable reliable products.