Flutter is a self-excited vibration under the interaction of the inertial force, aerodynamic force, and elastic force of the structure. After the flutter occurs, the aircraft structures will exhibit limit cycle oscillation, which will cause catastrophic accidents or fatigue damage to the structures. Therefore, it is of great theoretical and practical significance to study the aeroelastic characteristics and flutter control for improving the aeroelastic stability of aircraft structures. This paper reviews the recent advances in aeroelastic analysis and flutter control of wings and panel structures. The mechanism of aeroelastic flutter of wings and panels is presented. The research methods of aeroelastic flutter for different structures developed in recent years are briefly summarized. Various control strategies including the linear and nonlinear control algorithms as well as the active flutter control results of wings and panels are presented. Finally, the paper ends with conclusions, which highlight challenges of the development in aeroelastic analysis and flutter control, and provide a brief outlook on the future investigations. This study aims to present a comprehensive understanding of aeroelastic analysis and flutter control. It can also provide guidance on the design of new wings and panel structures for improving their aeroelastic stability.
In this paper, the two-dimensional (2-D) ultrasonic wave propagation problem in an elastic half-space with a localized damaged zone is numerically simulated by a mapped Chebyshev pseudo-spectral collocation method [1]. The considered damaged zone, which is embedded in an undamaged host medium, is modelled by a nonlinear elastic and viscoelastic constitutive law. Classical nonlinear elastic and nonclassical hysteretic material behaviors are separately considered and evaluated. In particular, the classical nonlinear elasticity theory of Murnaghan [2] is implemented, while the hysteretic material behavior is modelled by the Duhem-model. To transfer the constitutive relations from the one-dimensional (1-D) to the 2-D case the Kelvin decomposition method is used. Furthermore, Convolutional Perfectly Matched Layers (CPML's) are used to simulate the semi-infinite elastic half-space. The computed time-domain signals are transformed to the frequency-domain and subsequently analyzed for different degrees of the wave attenuation and nonlinearity in the damage zone. The applications of the nonlinear ultrasonic technique are discussed based on the numerical results.
The control and manipulation of acoustic and elastic waves is an important research topic in engineering sciences. In acoustics, an adequate combination of different materials can contribute to an efficient and broadband sound isolation. The realization of a vibration‐free environment for high‐precision mechanical systems in laboratories and measuring environments is also desirable in many practical cases. Therefore, advanced materials and structures with outstanding acoustic and elastodynamic properties are of great importance in engineering applications. In this paper, a numerical tool based on the finite element method (FEM) is developed for computing the dispersion relations or band structures of two‐dimensional (2D) phononic crystals (PCs) composed of an elastic matrix and periodically distributed cylindrical inclusions.
In this paper the 3-D wave propagation in an infinite elastic solid with a spherical damage is numerically simulated by a mapped staggered Chebyshev pseudo-spectral collocation method. In the numerical simulation process, the so-called Convolutional-Perfectly-Matched-Layers (CPML) are used to model the absorbing boundaries and the wave excitations are specified inside the corresponding physical domain. Furthermore, to consider different damage models the classical nonlinear elastic and non-classical hysteretic material laws are used. The main objective of this study is to evaluate the influences of the particular wave modes and the mixing of the incident waves on the generated nonlinear scattered wave field. To analyze the specific scattered wave fields around the spherical damage region the computed time-domain signals are transformed to the frequency-domain.
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