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| Vibration response method for liquid-filled thin cylindrical shell with crack damage |
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Abstract Thin cylindrical shell fluid shock vibration response is a complex fluid-structure interaction (FSI) issue, and with importance significance to the state monitoring and damage recognition of thin shell. Based on the Flügge shell stress theory, the high-order partial differential equations (PDE) of thin shell motion are set up, and the system vibration response is obtained by the wave propagation method. The peripheral fluid is defined as the ideal sound media, and the sound pressure field is described by the Helmholtz equation. According to the above hypothesis, the forced vibration response and evolution regularities of thin cylindrical shell considering fluid-structure interaction are acquired. To conduct the recognition for crack damage of thin shell, the partial flexibility matrix is constructed by the facture mechanical principles, in combination with the breathing linear spring model (LSM), the adjacent stress and displacement conditions are built up. Consequently, the forced vibration response of liquid-filled thin cylindrical shell with crack is obtained, and a vibration power flow based crack damage recognition method is presented. The results showed that the displacement responses on the radial, axial and circumferential directions of liquid-filled thin cylindrical shell are with apparent differences by the nonlinear excitations; the peak values of radial and axial displacements take on distance delay phenomenon; the radial displacement contains more peak values, and has more close relation with fluid pulse excitation; the crack can decrease the partial flexibility and system natural frequency, and can change the power flow characteristics of the FSI system; by the increasing of crack depth, the transmission coefficient of vibration wave will be decreased; the normalized input power flow can recognize the crack damage of liquid-filled thin cylindrical shell. This research not can provide useful references to the modeling-solving of liquid-filled thin shell vibration response, but can offer potential solution scheme for the structure crack recognition under the condition of fluid-solid coupling.
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Received: 25 July 2018
Published: 22 February 2019
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2019, Vol. 40 
