3-D sloshing of liquid filled laminated composite cylindrical tank under external excitation

The use of laminated composite materials in aircraft or automobile structures, though very common due to various advantages of these materials, often escalates the overall noise and vibration level. An active structural acoustic control (ASAC) strategy based on a frequency weighted optimal H2 controller is developed in the present work to attenuate the transmitted sound into an enclosure surrounded by laminated composite panels. A state-space model based on a two-way coupled fluid-structure interaction analysis using Green’s theorem is proposed to include the influence of the flexible panels on the enclosed fluid (air) and vice-versa. Few points within the cavity are identified as the observer locations based on the maximum sound pressure level (SPL) within the enclosure due to external mechanical excitation. The SPL averaged over these locations is used as the performance vector for the proposed H2 controller. A feedback control strategy is then developed using surface bonded collocated IDE-PFC actuators and PVDF sensors while optimizing the quadratic H2 norm between the external excitation and the performance vector with a limit on the actuation voltage. Numerical simulation shows a maximum of 11.4 dB of averaged SPL reduction achieved inside the enclosure for a particular configuration.

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Dynamic response of structure coupled with liquid sloshing in a laminated composite cylindrical tank with baffle

Finite Elements in Analysis and Design ◽

10.1016/j.finel.2010.07.001 ◽

2010 ◽

Vol 46 (11) ◽

pp. 966-981 ◽

Cited By ~ 28

Author(s):

K.C. Biswal ◽

S.K. Bhattacharyya

Keyword(s):

Dynamic Response ◽

Laminated Composite ◽

Liquid Sloshing ◽

Cylindrical Tank

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A TEM study of the interface between organic matrix and aragonite in a biological hard tissue, nacre

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100129759 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1024-1025

Author(s):

Jun Liu ◽

Katie E. Gunnison ◽

Mehmet Sarikaya ◽

Ilhan A. Aksay

Keyword(s):

Mechanical Properties ◽

Ion Beam ◽

Laminated Composite ◽

Organic Matrix ◽

Pearl Oyster ◽

Interfacial Structure ◽

Interfacial Region ◽

Thin Sections ◽

Organic Layers ◽

Transmission Electron

The interfacial structure between the organic and inorganic phases in biological hard tissues plays an important role in controlling the growth and the mechanical properties of these materials. The objective of this work was to investigate these interfaces in nacre by transmission electron microscopy. The nacreous section of several different seashells -- abalone, pearl oyster, and nautilus -- were studied. Nacre is a laminated composite material consisting of CaCO3 platelets (constituting > 90 vol.% of the overall composite) separated by a thin organic matrix. Nacre is of interest to biomimetics because of its highly ordered structure and a good combination of mechanical properties. In this study, electron transparent thin sections were prepared by a low-temperature ion-beam milling procedure and by ultramicrotomy. To reveal structures in the organic layers as well as in the interfacial region, samples were further subjected to chemical fixation and labeling, or chemical etching. All experiments were performed with a Philips 430T TEM/STEM at 300 keV with a liquid Nitrogen sample holder.

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