bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micropropulsion
Authors: Ketsdever Andrew D. 
Published: December 2010

AbstractA wide range of micropropulsion systems have been proposed, designed, and developed in an effort to revolutionize space operations. Micropropulsion is generally defined as a propulsion system capable of producing a change in momentum on a microspacecraft (i.e., a spacecraft with a mass less than 100 kg). Allowing a broad definition of micropropulsion includes a wide range of propulsion systems ranging from scaled‐down versions of existing larger‐scale thrusters to specially designed thrusters that utilize advanced micro‐fabrication techniques. This section briefly summarizes design constraints, scaling laws, mission requirements, and application of micropropulsion systems. This section also summarizes the current state‐of‐the‐art in micropropulsion system development including both microchemical and micro‐plasma concepts.
Laser Propulsion
Authors: Komurasaki Kimiya , Wang Bin 
Published: December 2010

Abstract“Beamed Energy Propulsion” is distinguished by its use of a collimated laser or microwave beam that enables long‐distance wireless power supply, no‐fuel airbreathing flight, high heating rates (detonation and ablation) by beam focusing, and other useful features. Remotely powered space propulsion is a potential alternative to chemical and electric propulsion. Compact onboard laser thrusters also provide unique features. This chapter presents a worldwide review of beamed energy propulsion studies, most of which have been reported at the series of International Symposium on Beamed Energy Propulsion (ISBEP).
Magnetic Plasma Sails
Authors: Winglee Robert M. 
Published: December 2010

AbstractMagnetic plasma sails can augment spacecraft propulsion by the deflection of charge particles from an external source, thereby utilizing energy and momentum that is not actually carried on board the spacecraft. The external source could be the solar wind that has speeds of 350–800 km s−1, which is more than an order of magnitude faster than most plasma propulsion system presently being considered. Because of the tenuous nature of the solar wind, a mini‐magnetosphere needs to be created by the injection of low energy plasma that expands the magnetic field out to tens of kilometers. This expansion can be achieved by induced plasma currents stemming from the plasma interaction with a base dipole magnet field. An alternative use of plasma sails is the deflection of beamed plasmas. This latter application opens up a host of new applications, including raising or lowering of orbits of spacecraft around the Earth, as well as fast missions to the planets. New developments in magnetic nozzles opens up the possibility of having collimated plasma beams propagating over large distances to achieve efficient distant beamed plasma applications.
Radio‐Frequency and Microwave Thrusters
Authors: Micci Michael M. 
Published: December 2010

AbstractBoth radio‐frequency (RF) and microwave electromagnetic energy can be used to heat a propellant gas to plasma temperatures followed by a gasdynamic converging{‐‐}diverging nozzle expansion in an electrothermal rocket mode. RF energy can be coupled to a gas either capacitively or inductively. Capacitive coupling operates effectively only at low gas pressures that are not desired in a thruster concept due to frozen flow losses. Inductive coupling has been shown to effectively couple RF energy to gases at atmospheric and higher pressures. However, because inductively coupled plasmas fill the entire absorption chamber, heat losses to the chamber walls are severe. Microwave energy can be used in one of several modes including, resonant microwave cavity, surface wave or propagating plasma modes, to ignite and sustain plasmas that can be localized away from any walls, thus reducing heat losses from the thruster. State‐of‐the‐art microwave thrusters utilize the microwave resonant cavity mode, where a standing wave is created within a cavity with plasma formation only at regions of high electric field intensity. Microwave thrusters have been demonstrated at frequencies ranging from 915 MHz to 14.5 GHz at power levels from 10 to 11 000 W. High specific impulses have been measured for microwave thrusters for both helium and ammonia propellants.
Fusion Propulsion
Authors: Kammash Terry 
Published: December 2010

AbstractNext to antimatter annihilation reactions, fusion nuclear reactions produce more energy per unit mass than other energy sources considered suitable for space propulsion. The mass converted to energy in fusion reactions is almost an order of magnitude larger than that in fission reactions, and several orders of magnitude larger than chemical reactions. The fusion fuel, which can also serve as a propellant, must, however, be heated to very high temperatures, comparable to those inside the sun, in order to achieve ignition, and for the reactions to become self sustaining. At such temperatures the fusion fuel becomes ionized consisting of unbound, freely moving charged particles, namely electrons and ions often referred to as “plasma.” In order to produce energy exceeding that required to heat it to ignition, the plasma must be confined long enough to allow the ions to undergo fusion reactions. Such confinement is generally achieved in one of two ways, “magnetic” or “inertial.” Both of these approaches have been investigated for utilization in space propulsion. In what follows, the underlying principles of the use of fusion energy in space propulsion will be examined, and some representative concepts of both confinement approaches will be addressed.
Space Power Trends
Authors: Spanjers Gregory , Roberts Thomas 
Published: December 2010

AbstractSize and performance characteristic limits are discussed for government and commercial spacecraft classes. Potential future sources of space power are described. These technologies are not intended to be all‐inclusive; however, electrodynamic tethers, nuclear fission reactors, nuclear fusion, and antimatter provide a good range of the various stages of research and development encountered as technologies are matured for space flight. Historical and present‐day spacecraft power levels show an ever‐increasing rise in the maximum available power, although the use of these high power levels is limited to a small few commercial communications spacecraft. Peak power levels today, excluding the International Space Station, are 18‐‐20 kW, although this is expected to rise to the 25‐‐30 kW range in the near future. Early high‐power spacecraft relied on nuclear fission reactors for critical military missions, primarily for the Soviet government. These were retired after the 1980s due to improved photovoltaic power‐generation technology. At present the power levels used for earth‐orbiting spacecraft are spread across the 0‐‐20 kW range, with the distribution dominated by the constellations programs. Interplanetary space continues to be restricted to low power levels afforded by Radioisotope Thermoelectric Generators, until research can mature technologies such as nuclear to provide high‐power capability far from the sun.
Variational Principles in Structural Mechanics
Authors: Shaw John A. , Elliott Ryan S. 
Published: December 2010

Abstract
This chapter introduces the calculus of variations and associated mathematical operators on functionals, which are used to formulate boundary value problems in structural mechanics. Weak forms of equilibrium are derived in terms of the principle of virtual work and the theorem of minimum potential energy. These are used to establish the governing field equations (Euler–Lagrange differential equations) and associated geometric, natural, or mixed boundary conditions. Weak forms of kinematic compatibility are derived in terms of the principle of complementary virtual Work and the theorem of minimum complementary potential energy. Examples are provided for each.
Finite Element Methods of Structural Analysis
Authors: Hulbert Gregory M. 
Published: December 2010

Abstract
This chapter presents an overview of two widely used numerical methods for structural analysis. The Rayleigh–Ritz method employs a global perspective of approximation, while the finite element method (of Galerkin form), employs a local approximation basis. Both methods are introduced via a simple truss example. For the finite element method, the construction of element stiffness matrices and loading vectors are shown starting from the general differential equations for truss response, through developing a weak form of the equations, to the Galerkin approximation method and then to specific choices of assumed solutions. Finite element generation, element assembly and global solution techniques are articulated. The generality of the finite element approach is demonstrated by application to beam bending theory.
Elements of Structural Dynamics
Authors: Kosmatka J. B. 
Published: December 2010

Abstract
Modern aerospace vehicles have become larger, lighter, and more flexible, where the effects of dynamic loading can produce large structural oscillatory responses leading to potential catastrophic failures. It is imperative that practicing aerospace engineers are knowledgeable of the system variables that can be used to control (or limit) these large dynamic oscillations as well as understanding the analytical tools that can be used to model these systems and predict the system response. These tools range from approximate single‐ and multidegree of freedom lumped mass models to large‐scale finite element models, where to keep the problem tractable a limited number of vibration modes are used in the response predictions. In addition, closed‐form solutions provide valuable insight into the trends of this complex behavior, as well as providing benchmark cases for validating approximate solutions. In this chapter, the analytical tools are reviewed for both approximate and closed‐form approaches, where numerous results are presented that highlight techniques for controlling the system response.
Static and Dynamic Aeroelasticity
Authors: Weisshaar Terrence A. 
Published: December 2010

AbstractAeroelasticity is concerned with the consequences created by interactions among aerodynamic forces, structural deformation, and motion of aerodynamic and hydrodynamic surfaces. Aeroelasticity has four primary effects: (i) lift redistribution that changes external loads; (ii) changes in aircraft trim and dynamic response; (iii) control effectiveness, including aileron reversal, which limits maneuverability; and (iv) aircraft structural dynamic response, in particular buffeting and flutter. A simple model is used to explain some of these effects.Aeroelastic effects have plagued aircraft from the beginning of flight, sometimes delaying technology transition. Early designs suffered from tail flutter and aileron‐wing flutter that led to in‐flight aircraft destruction. Flutter is a self‐excited structural dynamic instability that occurs when, at high speeds, wing or tail surface vibration extracts energy from the airstream. Today, aircraft development includes extensive, expensive analysis and testing to provide safe operation and prevent flutter.Solutions to aeroelastic problems nearly always include adding structural weight. Aeroelastic structural stiffness tailoring and active aeroservoelastic control are alternative remediation and exploitation methods. These efforts have led to modern designs such as the X‐29 research aircraft and the FA‐18 Active Aeroelastic Wing. A list of standard textbooks and major references is included.
Transonic Nonlinear Aeroelasticity
Authors: Dowell Earl , Bendiksen Oddvar , Edwards John , Strganac Thomas 
Published: December 2010

AbstractA review of the state of the art of transonic nonlinear aeroelasticity is presented. The discussion begins with a description of the generic nonlinear aeroelastic behavior that may occur followed by a summary of lessons learned from flight experience. Physical sources of nonlinear behavior are identified in both the aerodynamic fluid flow and the structure. Methods for the efficient computation of unsteady aerodynamic forces are summarized and then the chapter concludes with a discussion of correlation of theory and experiment for flutter boundaries in transonic flow and limit cycle oscillations (LCOs) arising from a variety of physical sources for several distinct aeroelastic configurations.
Panel Flutter
Authors: Dowell Earl H. , Bendiksen Oddvar 
Published: December 2010

AbstractPanel flutter or the flutter of plates and shells differs in some important respects from the classical flutter of airfoils and wings. These include (i) streamwise bending deformations which are more important than spanwise deformations, (ii) the effects of nonlinear structural forces which typically become significant when the plate deformations are on the order of the plate thickness, and (iii) the impact of viscous boundary layer effects in the transonic flow regime.It is also sometimes said that panel flutter only occurs at supersonic Mach numbers. And that is true if the leading and trailing edges of the panel are fixed, but not if the trailing edge is free. In the latter case the phenomenon is more analogous to the flutter of a flag and can occur in all speed regimes including subsonic flow. This recent work on transonic and subsonic panel flutter is considered here as well.In the present chapter, the essential elements of panel flutter are described, the essence of the extant mathematical models reviewed and representative comparisons between theory and experiment cited.
Aeroservoelasticity
Authors: Mukhopadhyay Vivek , Livne Eli 
Published: December 2010

AbstractThe engineering field of aeroservoelasticity in flexible flight vehicles involves mathematical modeling, analysis, and control of the interaction between aerodynamics, structural, and flight dynamic systems along with wind tunnel and flight testing of the advanced active control technology. Adverse aerodynamic‐structure‐control interactions of flexible aircrafts have been a major problem throughout the history of aeronautics. If the flexible vehicle structure is not properly designed, aerodynamic‐structure interactions at high speeds may cause excessive dynamic responses leading to an instability or catastrophic structural failure. In this chapter, fundamentals of these aerodynamic‐structure interactions and optimal feedback control of the resulting flight dynamic instabilities are presented. First, a brief historical review of the evolution of aeroservoelasticity and active control of aeroelastic responses is presented. Then, basic mathematical formulation and analytical modeling techniques for a general aeroservoelastic system along with fundamentals of optimal robust feedback control law design processes are outlined. Techniques for large flexible aircraft structural deformation modal control, bending torsion flutter suppression, and gust load alleviation systems are explained. Two examples of research projects are presented that have demonstrated flutter suppression and gust load alleviation of aeroservoelastic models in wind tunnel tests. Finally, possible future directions of this exciting field of applied aerospace engineering technology and their applications to advanced aircrafts are discussed.
Aeroelastic Testing and Certification
Authors: Cooper Jonathan , Lind Rick , Wright Jan 
Published: December 2010

Abstract
All aircraft must be certified under airworthiness regulations in order to ensure that they are safe from any aeroelastic instability and do not exceed design loads throughout the entire desired flight envelope. The certification process is a combination of numerical simulations validated by a range of different experimental tests. This chapter describes the main analyses and tests that must be performed in order to satisfy the airworthiness regulations relating to aeroelasticity.
Fundamentals of Discretization Methods
Authors: de Borst René 
Published: December 2010

AbstractThis chapter gives a concise introduction into modern discretization concepts that are used for the stress analysis of structures and in fluid–structure interaction problems.Departing from a by now classical concept, namely the finite element method, mesh‐free methods and partition‐of‐unity‐based discretization methods are introduced. Since the majority of the structural applications in aerospace engineering concern thin‐walled structures, some attention is given to shell elements. In view of the rapidly increasing use of laminated composites, interface elements are also briefly treated.Furthermore, the growing importance of multiscale analysis as a new paradigm is discussed.
Finite Element Analysis of Composite Plates and Shells
Authors: Reddy J.N. , Arciniega Roman A. , Moleiro Filipa 
Published: December 2010

Abstract
In this chapter, an overview of recent developments on finite element analysis of composite plates and shells are presented. Two major developments in the last decade by the author and his colleagues have been in the formulation of (1) least–squares finite element models of plates and (2) the weak‐form Galerkin finite element formulations of first‐order and third‐order shell theories. The least–squares formulations are based on the first‐order shear deformation theory, while the weak‐form Galerkin is based on the first‐order as well as the third‐order shear deformation theories. Results using the weak‐form Galerkin finite element model based on improved 7‐parameter first‐order theory are also included for geometrically nonlinear cases. The least–squares finite element models of plates are based on mixed formulations in which displacements as well as stress resultants are treated as the unknown field variables. The weak‐form Galerkin finite element models are displacement‐based. In the latter, a family of high‐order Lagrange interpolation functions (with equally spaced nodes and Gauss–Lobatto–Legendre nodes) is used to prevent shear locking. Numerical results are presented for a number of benchmark problems involving isotropic, laminated composite, as well as functionally graded plates and shells.
Meshfree Discretization Methods for Solid Mechanics
Authors: Rabczuk Timon , Bordas Stéphane P.A. , Askes Harm 
Published: December 2010

AbstractMeshfree methods are used for the spatial discretization of partial differential equations, but in contrast to finite element methods, they do not employ elements in the construction of the interpolants. Instead, a set of nodes is accompanied by a domain of influence for each node, whereby the overlap of domains of influence accounts for the interconnectivity between nodes. In this chapter, we will treat the formulation, implementation, and application to solid mechanics of meshfree methods. The focus will be on the element‐free Galerkin method but we will also provide an overview of other meshfree methods. As regards the applications, we will treat two major classes: firstly, incorporating discontinuities in meshless interpolations and secondly, exploiting the hypercontinuity of meshfree shape functions. Finally, we will discuss some urban myths surrounding meshfree methods, the relation with the new generation of node‐based finite element methods, and the future of meshfree methods.
Extended Finite Element Methods
Authors: Wells Garth N. 
Published: December 2010

Abstract
The extended finite element method is a powerful approach for simulating propagating cracks. It relies on the partition of unity property of finite element shape functions to introduce special functions locally, such as the singularity terms from linear elastic fracture mechanics or discontinuous functions to represent an evolving crack surface. The method is described here in the context of linear elastic fracture mechanics and cohesive crack propagation.
Adaptive Mesh Generation and Visualization
Authors: Remacle Jean‐Francois , Geuzaine C. , Compère Gaëtan , Helenbrook B. T. 
Published: December 2010

AbstractThis chapter discusses some of the main components of mesh adaptation and solution visualization. Theoretical results on the specification of optimal meshes are reviewed and then demonstrated for several 2D and 3D example problems. Some of the more challenging aspects of mesh adaptation are discussed including mesh adaptation for problems with a time evolving solution, for problems where the geometry is specified by an external geometrical model (a CAD model), mesh adaptation for high‐order finite element methods, and anisotropic mesh adaptation. The discussion of solution visualization shows how many of the same techniques used for mesh adaptation can be used for fast and accurate visualizations of high‐order finite element data.
Computational Dynamics
Authors: Bottasso Carlo L. 
Published: December 2010

AbstractThe simulation of aerospace systems leads to multidisciplinary problems dealing with the modeling of complex flexible mechanisms interacting with various other coupled fields. Structural models of the elastic bodies are connected together by mechanical joints and coupled to aerodynamic models, to hydraulic and electromechanical subsystems, engine, sensors, and other elements. Modern multibody dynamics technology, based on a combination of linear and nonlinear finite element methods, techniques for enforcing constraints, coupled simulation methods, and accessory algorithmic tools, is capable of delivering models of high sophistication for a wide range of highly demanding industrial applications in aerospace engineering.
Fundamentals of Fluid–Structure Interaction
Authors: van Brummelen E. Harald , Geuzaine Philippe 
Published: December 2010

Abstract
Fluid–structure interaction is of fundamental importance in many aerospace‐engineering applications on account of its manifestation in aeroelasticity, aerothermoelasticity, and heat transfer.
This chapter is concerned with the fundamentals of fluid–structure interaction and of computational methods for this class of problems. Both kinematic/dynamic and thermal/thermodynamic interactions are considered.
We review the conventional Arbitrary–Lagrangian–Eulerian and three‐field formulations to accommodate the motion of the fluid domain. In addition, we focus on the precise interpretation and proper enforcement of interface conditions. Finally, we examine the strength of the kinematic/dynamic and thermal/thermodynamic coupling in fluid–structure‐interaction problems and its relation to stability and convergence of numerical solution techniques.
Historical Perspective on Experimental Methods
Authors: Ravi‐Chandar Krishnaswamy 
Published: December 2010

AbstractAerospace structures are high‐performance structures with stringent requirement on size, weight, load‐carrying capacity, reliability and durability. Over the past century, significant advances have been made in furthering aerospace structures technology. Today's aerospace structures have benefited from significant experimental investigations that have revealed modes of failure – from buckling to fatigue to plastic deformation to fracture that occur in these structures. Experimental characterization, using prototypes and failure investigations, have enabled the generation of a physical understanding of the root causes of degradation of structural performance and the development of procedures for enhancing the reliability and durability. A brief review of some major advances triggered by failures is provided in this chapter to highlight the role of experiments in this process.