bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic (Vibration) Testing: Design Certification of Aerospace System
Authors: Aggarwal Pravin K. 
Published: December 2010

Abstract
Certification of the design is part of the overall qualification process for a space system and its components. The purpose of the design certification testing is to ensure that verification/validation demonstrates design compliance with functional and performance requirements. It helps establish the proof that a product will accomplish the intended purposes. Various types of dynamic testing of structures for certification purposes are described in this section, including vibration, shock and acoustic testing. Modal testing is discussed as it frequently complements dynamic testing and is part of the structural verification/validation process leading up to design certification. Examples of dynamic and modal testing are presented as well as the common practices, procedures and standards employed.
Fatigue Properties Characterization of Structural Metals, Composites and Sandwich Structures
Authors: Pelegri Assimina A. , Pan Yi 
Published: December 2010

AbstractThe fatigue properties of materials are necessary for life prediction of material or structure to ensure structural integrity and safety in cases where the structures are subjected to fatigue stress cycles. Several fatigue testing techniques for structural metals, composites, and sandwich structures at coupon level are discussed in this chapter. General considerations such as instrumentation and specimen design are introduced, followed by brief descriptions of the techniques applied to determine stress‐life, strain‐life, and fatigue crack‐growth rate for structural metals and composite materials and the corresponding phenomenological models. Fatigue testing technique applicable to sandwich core materials due to core shear failure is covered too. Procedures for testing the effects of environmental factors such as temperature and moisture on fatigue properties are briefly discussed.
Delamination Toughness Characterization of Laminated Composites
Authors: Davidson Barry D. 
Published: December 2010

AbstractThe state‐of‐the‐art in delamination toughness characterization is reviewed. Widely used methods for determining mode I, II, and mixed‐mode I‐II delamination toughness of laminated composites are first presented. This is followed by a description of the evolving methods for characterizing the mode III and the mixed‐mode toughness under conditions where mode III is present. The effects of mode ratio, temperature, moisture, and interfacial ply orientation on toughness are discussed, as is the representation of static delamination toughness data via failure loci and failure surfaces. Methods are presented to evaluate threshold toughnesses for the onset of fatigue delamination growth and to determine growth rates for stable delamination advance under fatigue loading. The relative advantages of characterizing fatigue delamination growth using energy release rate versus stress intensity factor are also addressed.
Modal Vibration Methods in Structural Health Monitoring
Authors: Worden Keith , Inman Daniel J. 
Published: December 2010

AbstractThis chapter addresses vibration‐based structural health monitoring (SHM) and issues related to using modal data to detect damage in structures using an SHM philosophy. The basic premise is that changes in modal information obtained through providing a known vibration signal in and measuring the vibration response will indicate a change in the structures' mass, damping, or stiffness properties. Furthermore, these changes are thought to correspond to damage in the system. The following text discusses several such methods and examples of SHM through modal methods.
Impedance‐Based Structural Health Monitoring for Aerospace Applications
Authors: Park Gyuhae , Farrar Charles R. , Inman Daniel J. 
Published: December 2010

Abstract
Various experimental studies have demonstrated that an impedance‐based approach to structural health monitoring (SHM) can be an effective means of structural damage detection. Using the self‐sensing and active‐sensing capabilities of piezoelectric materials, the electromechanical impedance response can be monitored to provide a qualitative indication of the local health of a structure. The impedance method also has applications in the field of sensor self‐diagnostics and validation for determining the operational status of piezoelectric active sensors used in SHM. This chapter presents an overview and recent applications of the impedance‐based structural health‐monitoring technique.
Damage Prognosis for Metal and Composite Aerospace Structures
Authors: Adams Douglas E. , Jata Kumar V. 
Published: December 2010

AbstractIt is envisioned that aerospace systems will someday be designed with automated damage prognosis technologies that are used to sense and predict the remaining life of structural components. The goal of implementing damage prognosis in an automated manner is to manage the uncertainties and high costs that are associated with current structural integrity management programs especially as new materials are adopted. This chapter reviews challenges and methods associated with estimating loads, diagnosing the damage state, and predicting the life of structural systems across multiple time and length scales. It is determined that multi‐multi methods that incorporate probabilistic modeling are needed to quantify and manage statistical uncertainties in structural damage prognosis. Applications involving rotary wing and fixed wing aircraft, rocket motors, and wind turbines are highlighted.
Design Principles for Aerospace Structures Utilizing
SHM
Authors: Haugse Eric D. , Young Gerould K. , Derriso Mark M. , Davis Christopher L. 
Published: December 2010

Abstract
Structural health management (SHM) and its related technologies offer the combined benefits of reducing maintenance costs while preserving or improving structural design performance. Advanced SHM technology implementation for in‐service aerospace platforms requires a disciplined approach to quantify how each application can provide benefit in the context of design practices and design and maintenance criteria. The focus of this chapter will be to describe SHM from a broader integrated design perspective and vision for the future. This will be accomplished by first providing a brief historical illustration of how design practices have evolved along with the ability to collect in‐service knowledge. An overview of SHM from a design and integration perspective will then be provided, followed by some examples that demonstrate SHM implementation in the context of a broader design and maintenance perspective.
Structural Materials: Aluminum and its Alloys – Fabrication Technologies
Authors: Schneider Judy A. 
Published: December 2010

AbstractAluminum alloys have a wide range of applications in the aerospace industry due in part to a high strength to weight ratio and resistance to corrosion. The relatively low melting temperature of these materials makes them amenable to variety of fabrication methods. Critical to the usage of these materials for aerospace structures is the ability to produce light‐weight structures, complex geometries, and joints of high integrity. The objective of this chapter is to compare the use of different fabrication processes commonly used in the aeronautical industry for aluminum alloys.
Titanium and Its Alloys: Metallurgy, Heat Treatment and Alloy Characteristics
Authors: Boyer Rodney R. 
Published: December 2010

AbstractTitanium is a very attractive material for aerospace applications due to its high strength:weight ratio, corrosion resistance and temperature capabilities; titanium is used in cryogenic applications as well as for elevated temperature applications up to ∼600°C. Another consideration, becoming more important with increased use of polymer matrix composites usage, is titanium is more compatible with composite materials than the other structural alloys when taking into account both corrosion and coefficient of thermal expansion compatibility with the graphite fibers in the composites. The rationale for using titanium will be discussed in detail and a brief description of the alloy types and their advantages and disadvantages will be presented in (see Titanium and its Alloys: Processing, Fabrication and Mechanical Performance). A wide range of heat treatments can be used for Ti alloys, which can have a significant effect on their properties combinations, which will be explained. A unique aspect of titanium is that even the modulus can be modified by heat treatment and/or processing. Relatively new, emerging alloys are also covered.
Fiber‐Reinforced Polymer Composites: Manufacturing and Certification Issues
Authors: Engelstad Stephen P. , Koon Robert W. 
Published: December 2010

AbstractThis chapter is targeted as a high‐level primer for the basic requirements and issues regarding the certification and manufacturing of composite aircraft structure. It begins with a review of the general certification requirements. This includes discussion on material and process development, manufacturing and quality assessment, building block testing, analysis, structural testing, and supportability. Different manufacturing options are then reviewed, which cover material selections, material placement, resin infusion, curing, and joining options. A final discussion provides guidance on key issues in bonded versus mechanically fastened joints.
Load‐Bearing Laminated Composite Structures
Authors: Chan Wen S. 
Published: December 2010

Abstract

This chapter covers the description of the basic terminologies and load‐deformation relationships of fiber reinforced laminated composites. The terminologies include laminate coding, lamina and laminate coordinate systems, symmetric and unsymmetrical laminates, balanced and unbalanced laminates, antisymmetric laminate‐and quasi‐isotropic laminate. The elastic stress/strain relationship of lamina and the laminate constitutive relationship (classical laminated plate theory) are described. Illustrations of computational procedures of lamina stresses and lamina failure prediction in laminated structures are also included. The out‐of‐plane laminate failure criterion is briefly depicted. The extensional [

A

], coupling [

B

] and bending [

D

] stiffness matrices of laminate are explicitly expressed. The structural response of a laminate due to the components of the

A

,

B

and

D

matrices is also depicted in this article. The characteristics of laminates used in the primary structures for aerospace applications are described. Edge delamination, a unique behavior of load‐bearing laminate structures is also explained. Design approaches for laminate strength improvement are also addressed.
Fiber‐Reinforced Polymer Matrix Composites: Pressure Vessels for Aerospace Applications
Authors: Chang James , Newhouse Norman 
Published: December 2010

Abstract
A composite overwrapped pressure vessel (COPV) is a thin liner overwrapped by fiber reinforced polymer matrix composite material (FRPMC) through either wet filament winding process or layup with prepegs. Because of the weight benefit, space shuttle and International Space Station used COPVs for the storage of various fluids including gaseous oxygen, gaseous nitrogen, and gaseous helium. Other space systems such as launch vehicles and satellites also use COPVs in their propulsion or control subsystems. This chapter describes briefly the manufacturing process for producing a COPV and some key design and test requirements that are being imposed on space flight COPVs.
Lightweight Sandwich Structures
Authors: Vizzini Anthony J. 
Published: December 2010

AbstractLigh‐weight sandwich structures are utilized for their relatively high specific bending rigidity and strength. In addition, the core material can be selected to optimize the performance of the structure with respect to various transport phenomena such as fire retardation, thermal conduction, and sound transmission/absorption. Although sandwich structures can be seen as simple structural elements, their manufacture requires a series of steps necessitating the design of the manufacturing process often in tandem with the mechanical design.
Metal‐to‐Metal and Metal‐to‐Composite Bonded and Bolted Structural Joints
Authors: Ahn Junghyun , Duffala Nicole 
Published: December 2010

AbstractTo provide basic understanding of joints in aerospace composite structures, engineering approaches in designing composite bonded and mechanically fastened joints are described in this chapter. For each joint configurations, design and application aspect in aerospace structures were explained. Fundamental methods behind theoretical derivation of each joint configuration are explained. As an example for a real‐life design implementation of hybrid joints, integrated analysis approach using finite element analysis is presented at the end of chapter.
Mechanical Behavior of Nanomaterials
Authors: Chasiotis Ioannis 
Published: December 2010

Abstract
Nanomaterials for aerospace applications are dominated by nanostructured polymer matrix composites that are designed to improve on the mechanical, electrical, and thermal properties of polymers and polymeric matrices in laminate and woven composites. The design, manufacturing, and evaluation of nanocomposites are currently in progress, and this chapter provides a discussion on the state‐of‐the‐art mechanical improvements provided by this class of nanostructured materials. The effects of nanoparticle aspect ratio, size, and weight fraction on the elastic stiffness, mechanical strength, and fracture toughness are discussed in the perspective of existing knowledge on the mechanics of microscale particle reinforced polymers.
TiAl Intermetallics
Authors: Appel Fritz 
Published: December 2010

Abstract
Intermetallic titanium aluminides offer an attractive combination of low density and good oxidation and ignition resistance with unique mechanical properties. Thus, they are one of the few classes of emerging materials that have the potential to be used in demanding high‐temperature structural applications whenever specific strength and stiffness are of major concern. Advanced TiAl alloys have very complex microstructures with important features at the nanometer scale. There is an intimate correlation between the alloy chemistry, constitution, microstructure, and mechanical properties, which has to be considered in order to meet the desired properties. These concerns are addressed in this chapter through a global commentary on the physical metallurgy of TiAl‐based alloys. Particular emphasis is paid on recent developments of TiAl alloys with enhanced high‐temperature capability for application in aeroengines. Since TiAl alloys are now at the point of application, this chapter serves the materials' engineers as guidance in the huge body of literature concerning gamma titanium aluminide alloys going back nearly 20 years.
Metal‐Based Composite Materials for High‐Temperature Application
Authors: Withers Philip J. 
Published: December 2010

AbstractMetal matrix composites offer the potential for improved specific properties as well as increased elevated temperature performance relative to their unreinforced alloys. These are critical attributes for many aeroengine applications, making composites attractive despite their higher cost. For brittle matrix systems such as intermetallics, reinforcement can also be used as a means of improving toughness. In this chapter, a wide range of long fiber and discontinuously reinforced composite systems are considered from an aeroengine perspective based on aluminum, titanium, and intermetallic matrices moving from moderate‐temperature systems towards hot ones. Processing methods appropriate to each type are described. Properties such as specific stiffness, strength, creep, and fatigue performance are considered. Another important aspect is the propensity to generate residual stresses as a function of the mismatch in thermal expansion between the phases. In the final section a range of potential aeroengine applications is examined.
Polycrystalline Nickel‐Based Superalloys: Processing, Performance, and Application
Authors: Mitchell Robert J. 
Published: December 2010

AbstractThis chapter provides an introduction to polycrystalline nickel‐based superalloys and their application in aero gas turbines as critical rotating components. The chapter outlines the severe operating conditions in which these alloys operate and how they and the environment have evolved over time. The basics of superalloy metallurgy are presented with reference to the role of solid solution strengthening, precipitation hardening, minor phases, and trace elements. The role of microstructure on mechanical properties is discussed with specific reference to grain size, precipitate size, morphology and distribution, and grain boundary character. Heat treatment technology and the role of heat treatments in determining both microstructure and mechanical properties are also discussed. Processing routes are presented, outlining the multiple complex steps that are used in production of these components. The chapter concludes by presenting a brief synopsis of some of the latest advances in the field of polycrystalline nickel‐based superalloys. The chapter contains useful figures and tables and a detailed reference list, proving an excellent starting point for further study in this field.
Beyond Nickel Based Superalloys
Authors: Tsakiropoulos Panos 
Published: December 2010

Abstract
In the most advanced gas turbine engines, the gas temperature exceeds the melting temperature of Ni based superalloys. Further improvements in the performance of gas turbines require operation of metallic materials at higher temperatures. Research programs on Nb and Mo silicide based alloys have demonstrated that these materials can offer attractive mechanical properties that justify their consideration as suitable candidate materials to replace Ni based superalloys in specific structural applications in gas turbine engines. The research has also demonstrated that oxidation behavior of developmental alloys can be significantly improved via selection of specific alloy elements. The ongoing research to develop new alloys is outlined with the emphasis on new metallic materials based on the refractory metals Nb and Mo. For the Nb based alloys, alloy development research based on the Nb–Si–Ti system with transition/refractory and free electron metal additions is reviewed. For the Mo based alloys, the review concentrates on alloys based on the Mo–Si–B and Mo–Si–Al systems.
Solid State Welding of Aeroengine Materials
Authors: Preuss Michael , Threadgill Philip 
Published: December 2010

Abstract
The development of advanced aeroengine materials with improved high temperature capability has led to the requirement of solid state welding, with friction welding being the most viable technique. Particularly common in the aeroengine industry are inertia and linear friction welding, which will be considered in this chapter. First, a brief historical overview of the development of these solid state joining techniques will be provided. This is followed by a description of the basics of the process and the fundamental aspects of inertia and linear friction welding. Central to friction welding is the heating of two metal interfaces by friction resulting in severe deformation and often very steep temperature gradients across the weld line. Consequently, a central aspect to understanding inertia and linear friction welding is the detailed description of microstructural changes within the thermomechanically and heat affected zone, which ultimately impact on the mechanical properties of the weld and the residual stress development. Critical in the development of appropriate post weld heat treatments is to mitigate residual stresses without compromising the microstructure and mechanical properties. This is particularly difficult when working with dissimilar welds.
Superplastic Forming and Diffusion Bonding of Titanium Alloys
Authors: Ridley Norman 
Published: December 2010

AbstractFollowing a brief history of superplasticity leading to work that demonstrated the feasibility of combining superplastic forming (SPF) and diffusion bonding (DB) of α/β Ti alloys, the characteristics and the requirements for SP behavior are outlined. The importance of a high‐strain‐rate sensitivity, ormvalue, in inhibiting neck propagation in SP‐tensile specimens and differential thinning during SPF is explained. Factors affecting superplasticity in α/β Ti alloys are identified, important α/β alloys are listed, and the processing of material for SPF is described. The principles and practice of SPF and DB are explained, problems associated with the high temperatures involved are discussed, and procedures for testing the quality of diffusion bonds are considered. Typical aerospace applications of the products of DB and/or SPF are given.
Shape Memory Alloys
Authors: Shaw John A. , Churchill Christopher B. , Lagoudas Dimitris C. , Kumar Parikshith 
Published: December 2010

Abstract
An overview of shape memory alloys (SMAs) is presented, identifying some of the known alloy systems, their distinctive thermo‐mechanical properties, and the atomic‐level and microstructural mechanisms responsible for their remarkable behaviors. Some less known and unusual phenomena in their thermo‐mechanical response are highlighted that have created pitfalls for the casual user. A few interesting applications of SMAs, especially in the aerospace field, are briefly described that have enabled novel manufacturing techniques, deployable mechanisms, and adaptive structures.
Electroactive Polymers (EAP) as Actuators for Aerospace Engineering
Authors: Bar‐Cohen Yoseph 
Published: December 2010

AbstractMost biological systems that are larger than a bacteria use muscles as their actuators. Muscles are capable of lifting large loads with short time response in the range of milliseconds but they are driven by a complex mechanism that is very difficult to mimic. Electroactive polymers (EAP) are human made actuators that most closely emulate biological muscles earning them the moniker “artificial muscles”. Initially, EAP received relatively little attention due to their limited actuation capability. In the last twenty years a series of EAP materials have emerged that respond to electrical stimulation with a significant shape change. Using these materials as actuators, various novel mechanisms and devices were already demonstrated including robot fish, miniature gripper, loudspeaker, active diaphragm, catheter steering element,, and dust‐wiper. The impressive advances in improving their actuation strain capability are attracting the attention of engineers and scientists from many different disciplines. These materials are particularly attractive to biomimetic applications allowing for producing biologically inspired intelligent inventions. Increasingly, engineers are able to develop EAP actuated mechanisms that were previously considered science fiction. This chapter reviews the state of the art, challenges, and potential applications of EAP materials to aerospace engineering.
Materials in Space: An Introduction and Overview
Authors: Chambers Alan R. 
Published: December 2010

Abstract
The components of the space environment which affect the performance of materials in space are described. These include the gaseous atmosphere of low Earth orbit (LEO), atomic oxygen, radiation including vacuum ultraviolet, soft X‐rays and cosmic rays and debris both natural and man‐made. The effect of the environment on the performance of common spacecraft materials and components are identified and the developments in materials and design to combat degradation are considered. The paper serves as introduction to the more detailed contributions in this chapter.