Aeroelasticity

Aeroelasticity is the study of flexible structures situated in a flowing fluid. Its modern origins are in the field of aerospace engineering, but it has now expanded to include phenomena arising in other fields such as bioengineering, civil engineering, mechanical engineering and nuclear engineering. The present volume is a teaching text for a first, and possibly second, course in aeroelasticity. It will also be useful as a reference source on the fundamentals of the subject for practitioners. In this third edition, several chapters have been revised and three new chapters added. The latter include a brief introduction to `Experimental Aeroelasticity', an overview of a frontier of research `Nonlinear Aeroelasticity', and the first connected, authoritative account of `Aeroelastic Control' in book form. The authors are drawn from a range of fields including aerospace engineering, civil engineering, mechanical engineering, rotorcraft and turbomachinery. Each author is a leading expert in the subject of his chapter and has many years of experience in consulting, research and teaching.

Designed as both a textbook for advanced engineering students and a reference book for practicing engineers, this highly regarded work deals not only with the practical aspects of aeroelasticity, but the aerodynamic and structural tools upon which these rest. Accordingly, the book divides roughly into two halves: the first deals with the tools and the second with applications of the tools to aeroelastic phenomena. Topics include deformation of airplane structures under static and dynamic loads, approximate methods of computing natural mode shapes and frequencies, two-and three-dimensional incompressible flow, compressible flow, wings and bodies in three-dimensional unsteady flow, static aeroelastic phenomena, flutter, dynamic response phenomena, aeroelastic model theory, model design and construction, testing techniques and more. Chapters have been designed to progress from easy to difficult so that instructors using this book as an elementary text in aeroelasticity will find their purposes served by simply using the first parts of selected chapters. Helpful appendixes deal with such mathematical tools as matrices and linear systems (prerequisites include the usual engineering mathematics courses and advanced calculus), while many numerical examples are included throughout the text. Engineering students as well as practicing engineers will find this work an unmatched treatment of the topic and an indispensable reference for their libraries.

Aircraft performance is influenced significantly both by aeroelastic phenomena, arising from the interaction of elastic, inertial and aerodynamic forces, and by load variations resulting from flight and ground manoeuvres and gust / turbulence encounters. There is a strong link between aeroelasticity and loads, and these topics have become increasingly integrated in recent years. Introduction to Aircraft Aeroelasticity and Loads introduces the reader to the main principles involved in a wide range of aeroelasticity and loads topics. Divided into three sections, the book begins by reviewing the underlying disciplines of vibrations, aerodynamics, loads and control. It goes on to describe simplified models to illustrate aeroelastic behaviour and aircraft response before introducing more advanced methodologies. Finally, it explains how industrial certification requirements for aeroelasticity and loads may be met and relates these to the earlier theoretical approaches used. Presents fundamentals of structural dynamics, aerodynamics, static and dynamic aeroelasticity, response and load calculations and testing techniques. Covers performance issues related to aeroelasticity such as flutter, control effectiveness, divergence and redistribution of lift. Includes up-to-date experimental methods and analysis. Accompanied by a website with MatLAB and SIMULINK programs that relate to the models used. Introduction to Aircraft Aeroelasticity and Loads enables the reader to understand the aeroelastic and loads principles and procedures employed in a modern aircraft design office. It will appeal to final year undergraduate and masters students as well as engineers who are new to the aerospace industry.

Introductory Guide on the Design of Aerospace Structures Developed from a course taught at Concordia University for more than 20 years, Principles of Aeroelasticity utilizes the author’s extensive teaching experience to immerse undergraduate and first-year graduate students into this very specialized subject. Ideal for coursework or self-study, this detailed examination introduces the concepts of aeroelasticity, describes how aircraft lift structures behave when subjected to aerodynamic loads, and finds its application in aerospace, civil, and mechanical engineering. The book begins with a discussion on static behavior, and moves on to static instability and divergence, dynamic behavior leading up to flutter, and fluid structure interaction problems. It covers classical approaches based on low-order aerodynamic models and provides a rationale for adopting certain aeroelastic models. The author describes the formulation of discrete models as well as continuous structural models. He also provides approximate methods for solving divergence, flutter, response and stability of structures, and addresses non-aeroelastic problems in other areas that are similar to aeroelastic problems. Topics covered include: The fundamentals of vibration theory Vibration of single degree of freedom and two degrees of freedom systems Elasticity in the form of an idealized spring element Repetitive motion Flutter phenomenon Classical methods, Rayleigh-Ritz techniques, Galerkin’s technique, influential coefficient methods, and finite element methods Unsteady aerodynamics, and more

In this new edition, the fundamental material on classical linear aeroelasticity has been revised. Also new material has been added describing recent results on the research frontiers dealing with nonlinear aeroelasticity as well as major advances in the modelling of unsteady aerodynamic flows using the methods of computational fluid dynamics and reduced order modeling techniques. New chapters on aeroelasticity in turbomachinery and aeroelasticity and the latter chapters for a more advanced course, a graduate seminar or as a reference source for an entrée to the research literature.

Aeroelastic phenomena arising from the interaction of aerodynamic, elastic and inertia forces, and the loads resulting from flight / ground manoeuvres and gust / turbulence encounters, have a significant influence upon aircraft design. The prediction of aircraft aeroelastic stability, response and loads requires application of a range of interrelated engineering disciplines. This new textbook introduces the foundations of aeroelasticity and loads for the flexible aircraft, providing an understanding of the main concepts involved and relating them to aircraft behaviour and industrial practice. This book includes the use of simplified mathematical models to demonstrate key aeroelastic and loads phenomena including flutter, divergence, control effectiveness and the response and loads resulting from flight / ground manoeuvres and gust / turbulence encounters. It provides an introduction to some up-to-date methodologies for aeroelastics and loads modelling. It lays emphasis on the strong link between aeroelasticity and loads. It also includes provision of MATLAB and SIMULINK programs for the simplified analyses. It offers an overview of typical industrial practice in meeting certification requirements.

The author's approach is one of continuum models of the aerodynamic flow interacting with a flexible structure whose behavior is governed by partial differential equations. Both linear and nonlinear models are considered although much of the book is concerned with the former while keeping the latter clearly in view. A complete chapter is also devoted to nonlinear theory. The author has provided new insights into the classical inviscid aerodynamics and raises novel and interesting questions on fundamental issues that have too often been neglected or forgotten in the development of the early history of the subject. The author contrasts his approach with discrete models for the unsteady aerodynamic flow and the finite element model for the structure. Much of the aeroelasticity has been developed with applications formerly in mind because of its enormous consequences for the safety of aircraft. Aeroelastic instabilities such as divergence and flutter and aeroelastic responses to gusts can pose a significant hazard to the aircraft and impact its performance. Yet, it is now recognized that there are many other physical phenomena that have similar characteristics ranging from flows around flexible tall buildings and long span bridges, alternate energy sources such as electric power generation by smart structures to flows internal to the human body. From the foreword: "For the theorist and applied mathematician who wishes an introduction to this fascinating subject as well as for the experienced aeroelastician who is open to new challenges and a fresh viewpoint, this book and its author have much to offer the reader." Earl Dowell, Duke University, USA