Linear Material Coupling Effect on Structural Damping of Composite Beams and Blades

Author(s):  
Dimitrios I. Chortis
2012 ◽  
Vol 94 (5) ◽  
pp. 1646-1655 ◽  
Author(s):  
Dimitris I. Chortis ◽  
Dimitris S. Varelis ◽  
Dimitris A. Saravanos

1996 ◽  
Vol 35 (2) ◽  
pp. 207-212 ◽  
Author(s):  
M. Coni ◽  
B. Benchekchou ◽  
R.G. White

2002 ◽  
Vol 9 (6) ◽  
pp. 283-291 ◽  
Author(s):  
S.W. Gong ◽  
K.Y. Lam

This paper deals with the transient response of layered composite beams subjected to underwater shock. The Doubly Asymptotic Approximation (DAA) method is employed in this study to treat the fluid-structure interactions. The effective structural damping and stiffness are formulated and incorporated in the fluid-structure-coupled equations, which relate the structure response to fluid impulsive loading and are solved using coupled finite-element and DAA-boundary element codes. The present computational method facilitates the study of transient response of the layered composite beams to underwater shock, involving the effects of structural damping and stiffness. In addition, the effect of free surface on the transient response of the layered beam to underwater shock is examined.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1518
Author(s):  
Zhicheng Xu ◽  
Xiaojian Ma ◽  
Qidong Yu ◽  
Jing Zhao ◽  
Dapeng Wang ◽  
...  

In order to resist bubble loading, anisotropic composite materials are the development direction of the future. The objective of this paper was to experimentally investigate the hydrodynamic performance of anisotropic laminate composite plates, with a focus on the effect of its anisotropic characteristics on single bubble migration. In these experiments, the bubble was generated in a transparent water tank filled with sufficiently degassed water by Joule heating at the connecting point of the electrodes through the discharge of a 6600 μF charge to 800 V, and a high-speed camera system with a recording speed of 40,000 frames per second was used to record the temporal evolution of bubble patterns and the dynamic responses of the laminated composite plates. The results are presented for two anisotropic cantilever composite beams with different ply angles, namely, 0° and 30°. Several variables, such as the shapes of the bubble, the curved trail of motion of the bubble center, bubble collapse time, and bubble initial standoff distances were extracted from the photographic images. The results showed that bubble migration near the 30° plate presents a curved bubble trail with an evident tilted angle during the collapse and rebound stages, which is very different from bubbles that all move vertically above the 0° plate. Furthermore, a characterization method for bubble migration was proposed to quantitatively describe the curved bubble trails and the deformation of the composite beams in temporal and spatial scales. This method shows that the curved bubble trails near the 30° plate are closely related to the dynamic response of composite beams, with a focus on the bending-twisting coupling effect.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.


2019 ◽  
Vol 7 (12) ◽  
pp. 1295-1307
Author(s):  
Xizhi Wu ◽  
Xueyou Huang ◽  
Xianjun Li ◽  
Yiqiang Wu

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