Yu Xiang

Bio: Yu Xiang is an academic researcher from Guangxi University of Technology. The author has contributed to research in topics: Constrained-layer damping & Vibration. The author has an hindex of 6, co-authored 7 publications receiving 85 citations.

New matrix method for analyzing vibration and damping effect of sandwich circular cylindrical shell with viscoelastic core

Abstract: Based on the linear theories of thin cylindrical shells and viscoelastic materials, a governing equation describing vibration of a sandwich circular cylindrical shell with a viscoelastic core under harmonic excitation is derived. The equation can be written as a matrix differential equation of the first order, and is obtained by considering the energy dissipation due to the shear deformation of the viscoelastic core layer and the interaction between all layers. A new matrix method for solving the governing equation is then presented with an extended homogeneous capacity precision integration approach. Having obtained these, vibration characteristics and damping effect of the sandwich cylindrical shell can be studied. The method differs from a recently published work as the state vector in the governing equation is composed of displacements and internal forces of the sandwich shell rather than displacements and their derivatives. So the present method can be applied to solve dynamic problems of the kind of sandwich shells with various boundary conditions and partially constrained layer damping. Numerical examples show that the proposed approach is effective and reliable compared with the existing methods.

A semi-analytical method and the circumferential dominant modal control of circular cylindrical shells with active constrained layer damping treatment

Abstract: To enhance the generality and flexibility of active constrained layer damped (ACLD) forms used in vibration control for circular cylindrical shells, the piezoelectric layer of the ACLD form is divided into several sub-blocks by thin insulated layers, and the sub-blocks are integrated on the viscoelastic layer continuously in the circumferential direction. In addition, on the basis of the authors' recent research on passive constrained layer damped (PCLD) circular cylindrical shells, the piezoelectric effects of the constrained layer (made of piezoelectric material) are further considered. Then, the integrated first-order differential equation for such an ACLD (partially treated in the axial direction) circular cylindrical shell is derived by reformulating the integrated first-order differential equation for the PCLD circular cylindrical shell. Next, employing the extended homogeneous capacity precision integration approach and the superposition principle, a high precision semi-analytical method is developed for solving the dynamic problem for such ACLD circular cylindrical shells. Subsequently, several kinds of circumferential modal control strategy are compared by the method presented. Furthermore, the concept of a circumferential dominant modal control strategy is proposed, which is different from the traditional modal control method. The numerical results show that, on applying the circumferential dominant modal control strategy, the ACLD cylindrical shell attenuates the vibration better. Lastly, some influence factors for the circumferential dominant modal control strategy affecting the damping effect of ACLD circular cylindrical shells are also investigated.

Nonlinear vibration analysis of fiber reinforced composite cylindrical shells with partial constrained layer damping treatment

Abstract: This research proposes a novel analytical model capable of accurately predicting the strain-dependent characteristics of fiber reinforced composite shells (FRCSs) with partial constrained layer damping (CLD) treatment by considering the nonlinearities of fiber reinforced composite and viscoelastic materials simultaneously. The nonlinear material properties are represented based on Jones-Nelson nonlinear theory, energy-based strain energy method, and complex modulus method. Then, the governing equations of motion for FRCSs are developed via Ritz method, and the identification procedure of nonlinear fitting parameters is also presented. By taking a T300 carbon fiber/epoxy resin cylindrical shell with partial CLD patches as an example, a series of experiments are carried out to validate the proposed modeling approach. Finally, the effects of material properties on nonlinear vibration behaviors of FRCSs covered with partial CLD patches are evaluated. Comparisons show that the proposed nonlinear model is more accuracy than that without considering strain dependence, where the maximum errors between the proposed model and measured data for natural frequencies, damping ratios and resonant response are 6.9%, 11.3%, and 11.2%, respectively.

Free vibration of circular cylindrical shell with constrained layer damping

Abstract: Free vibration characteristics of circular cylindrical shell with passive constrained layer damping (PCLD) are presented. Wave propagation approach rather than finite element method, transfer matrix method, and Rayleigh-Ritz method is used to solve the problem of vibration of PCLD circular cylindrical shell under a simply supported boundary condition at two ends. The governing equations of motion for the orthotropic cylindrical shell with PCLD are derived on the base of Sanders’ thin shell theory. Numerical results show that the present method is more effective in comparison with other methods. The effects of the thickness of viscoelastic core and constrained layer, the elastic modulus ratio of orthotropic constrained layer, the complex shear modulus of viscoelastic core on frequency parameter, and the loss factor are discussed.