The Rotating Beam Problem in Helicopter Dynamics


Book Description

The book addresses computational methods for solving the problem of vibration, response, loads and stability of a helicopter rotor blade modeled as a rotating beam with flap or out-of-plane bending. The focus is on explaining the implementation of the finite element method in the space and time domain for the free vibration, aeroelastic response and stability problems. The use of Floquet analysis for the aeroelastic stability analysis of rotor blades is also shown. The contents of the book will be useful to researchers in aerodynamics and applied mechanics, and will also serve well professionals working in the aerospace industry.




Smart Helicopter Rotors


Book Description

Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibration caused by dynamic stall. The exposition of ideas, materials and algorithms in this monograph is supported by extensive reporting of results from numerical simulations of smart helicopter rotors. This monograph will be a valuable source of reference for researchers and engineers with backgrounds in aerospace, mechanical and electrical engineering interested in smart materials and vibration control. Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control.




Proceedings of the 14th International Conference on Vibration Problems


Book Description

This book presents the select proceedings of the 14th International Conference on Vibration Problems (ICOVP 2019) held in Crete, Greece. The volume brings together contributions from researchers working on vibration related problems in a wide variety of engineering disciplines such as mechanical engineering, wind and earthquake engineering, nuclear engineering, aeronautics, robotics, and transport systems. The focus is on latest developments and cutting-edge methods in wave mechanics and vibrations, and includes theoretical, experimental, as well as applied studies. The range of topics and the up-to-date results covered in this volume make this interesting for students, researchers, and professionals alike.




Dynamics of Rotating Machines


Book Description

Enables engineers to understand the dynamics of rotating machines, from basic explanations to detailed numerical models and analysis.




Human Missions to Mars


Book Description

A mission to send humans to explore the surface of Mars has been the ultimate goal of planetary exploration since the 1950s, when von Braun conjectured a flotilla of 10 interplanetary vessels carrying a crew of at least 70 humans. Since then, more than 1,000 studies were carried out on human missions to Mars, but after 60 years of study, we remain in the early planning stages. The second edition of this book now includes an annotated history of Mars mission studies, with quantitative data wherever possible. Retained from the first edition, Donald Rapp looks at human missions to Mars from an engineering perspective. He divides the mission into a number of stages: Earth’s surface to low-Earth orbit (LEO); departing from LEO toward Mars; Mars orbit insertion and entry, descent and landing; ascent from Mars; trans-Earth injection from Mars orbit and Earth return. For each segment, he analyzes requirements for candidate technologies. In this connection, he discusses the status and potential of a wide range of elements critical to a human Mars mission, including life support consumables, radiation effects and shielding, microgravity effects, abort options and mission safety, possible habitats on the Martian surface and aero-assisted orbit entry decent and landing. For any human mission to the Red Planet the possible utilization of any resources indigenous to Mars would be of great value and such possibilities, the use of indigenous resources is discussed at length. He also discusses the relationship of lunar exploratio n to Mars exploration. Detailed appendices describe the availability of solar energy on the Moon and Mars, and the potential for utilizing indigenous water on Mars. The second edition provides extensive updating and additions to the first edition, including many new figures and tables, and more than 70 new references, as of 2015.




Nonlinear Analysis of Structures (1997)


Book Description

Nonlinear Analysis of Structures presents a complete evaluation of the nonlinear static and dynamic behavior of beams, rods, plates, trusses, frames, mechanisms, stiffened structures, sandwich plates, and shells. These elements are important components in a wide variety of structures and vehicles such as spacecraft and missiles, underwater vessels and structures, and modern housing. Today's engineers and designers must understand these elements and their behavior when they are subjected to various types of loads. Coverage includes the various types of nonlinearities, stress-strain relations and the development of nonlinear governing equations derived from nonlinear elastic theory. This complete guide includes both mathematical treatment and real-world applications, with a wealth of problems and examples to support the text. Special topics include a useful and informative chapter on nonlinear analysis of composite structures, and another on recent developments in symbolic computation. Designed for both self-study and classroom instruction, Nonlinear Analysis of Structures is also an authoritative reference for practicing engineers and scientists. One of the world's leaders in the study of nonlinear structural analysis, Professor Sathyamoorthy has made significant research contributions to the field of nonlinear mechanics for twenty-seven years. His foremost contribution to date has been the development of a unique transverse shear deformation theory for plates undergoing large amplitude vibrations and the examination of multiple mode solutions for plates. In addition to his notable research, Professor Sathyamoorthy has also developed and taught courses in the field at universities in India, Canada, and the United States.




Aerodynamics of the Helicopter


Book Description







Flexible Multibody Dynamics


Book Description

Arun K. Banerjee is one of the foremost experts in the world on the subject of flexible multibody dynamics. This book describes how to build mathermatical models of multibody systems with elastic components. Examples of such systems include the human body itself, construction cranes, cares with trailers, helicopers, spacecraft deploying antennas, tethered satellites, and underwater maneuvering vehicles. This book provides methods of analysis of complex mechanical systems that can be simulated in less computer time than other methods. It equips the reader with knowledge of algorithms that provide accurate results in reduced simulation time.