Guoyong Jin

Vibration characteristics and power transmission of coupled rectangular plates with elastic coupling edge and boundary restraints

Coupled-plate structures are widely used in the practical engineering such as aeronautical, civil and naval engineering etc. Limited works can be found on the vibration of the coupled-plate structure due to the increased mathematical complexity compared with the single plate structure. In order to study analytically the vibration characteristics and power transmission of the coupled-plate structure, an analytical model consisting of three coupled plates elastically restrained along boundary edges and elastically coupled with arbitrary angle is considered, in which four groups of springs are distributed consistently along each edge of the model to simulate the transverse shearing forces, bending moments, in-plane longitudinal forces and in-plane shearing forces separately. With elastic coupling condition and general boundary condition of both flexural and in-plane vibrations taken into account by setting the stiffness of corresponding springs, the double Fourier series solution to the dynamic response of the structure was obtained by employing the Rayleigh-Ritz method. In order to validate the model, the natural frequency and velocity response of the model are firstly checked against results published in literatures and the ANSYS data, and good agreement was observed. Then, numerical simulation of the effects of several relevant parameters on the vibration characteristics and power transmission of the coupled structure were performed, including boundary conditions, coupling conditions, coupling angle, and location of the external forces. Vibration and energy transmission behaviors were analyzed numerically. The results show that the power transmission can be significantly influenced by the boundary restraints and the location of excitation. When the excitation is located at the central symmetry point of the model, the energy flow shows a symmetrical distribution. Once the location deviates from the central symmetry point, the power circumfluence occurs and the vortex energy field is formed at high frequency.

Active control of sound transmission into an acoustic cavity surrounded by more than one flexible plate

This paper presents an investigation into the active control of sound transmission into a structural-acoustic coupled system. An enclosure with four acoustically rigid walls and two flexible plates is considered. One of the two plates through which a harmonic sound wave is transmitted into the enclosure, is called the incident plate, and the other as the receiving plate. Based on a fully coupled vibro-acoustic model, seven different control strategies, i.e. control configurations, are considered. They are: (a) use of the incident plate actuator, (b) applying acoustic control source in the cavity (called as cavity control), (c) use of the receiving plate actuator, (d) hybrid control system combining the incident plate actuator and the cavity control source, (e) hybrid control system combining the receiving plate control and the cavity control source, (f) simultaneous use of both the incident plate actuator and the receiving plate actuator, and (g) use of the combined acoustic actuator and structural actuators on both flexible panels. The effectiveness and performance of the control system corresponding to each configuration are compared and discussed through numerical simulations. The results show that two control system configurations, that is, the hybrid control system combining the incident plate actuator and the cavity control source and simultaneous use of both the incident plate actuator and the receiving plate actuator are desirable configurations in terms of the acoustic potential energy inside the enclosure.