Flap wise bending vibration and dynamic stability of rotating functionally graded material plates in thermal environments

Author(s):  
Ramu Inala ◽  
SC Mohanty

This paper deals with the study of the flapwise bending vibration and dynamic stability of rotating functionally graded material plates in thermal environments. A finite element formulation is derived for modal and dynamic stability analyses of rotating functionally graded material plates using first-order shear deformation theory. Temperature-dependent material properties of the plates are considered in the analysis and a simple power law is assumed for composition of constituent materials to vary along the thickness direction. The same power law is also proposed in thermal environments for temperature variation across the thickness of the plate. Some numerical results obtained from the present method are compared with numerical results available in the literature and are found to be in good agreement. Parametric investigation is carried out thoroughly to study the effect of the temperature rise, hub radius, and rotational speed on vibration and the dynamic stability of rotating plate in thermal environment. Bolotin’s method is used to generate the boundaries of stability and instability regions. These instability regions are plotted in the parameter space with the nondimensional dynamic load and excitation frequency. It is observed that the natural frequencies reduce with an increase in temperature rise. Increase in rotational speed and hub radius results in increase of natural frequencies of vibration. The rise in temperature leads to reduction in the dynamic stability of plate. Increase in rotational speed and hub radius enhances the dynamic stability of the rotating plate.

2017 ◽  
Vol 21 (4) ◽  
pp. 1316-1356 ◽  
Author(s):  
Dang T Dong ◽  
Dao Van Dung

This study presents a nonlinear vibration analysis of function graded sandwich doubly curved shallow shells, which reinforced by functionally graded material stiffeners and rested on the Pasternak foundation. The shells are subjected to the combination of mechanical, thermal, and damping loading. Four models of the sandwich shells with general sigmoid and power laws distribution are considered. The governing equations are established based on the third-order shear deformation theory. Von Kármán-type nonlinearity and smeared stiffener technique are taken into account. The explicit expressions for determining natural frequencies, nonlinear frequency–amplitude relation, and time–deflection curves are obtained by employing the Galerkin method. Finally, the fourth-order Runge–Kutta method is applied to investigate the influences of functionally graded material stiffeners, the boundary conditions, the models of the shells, thermal environment, foundation and geometrical parameters on the natural frequencies and dynamic nonlinear responses of the sandwich shells.


2017 ◽  
Vol 17 (10) ◽  
pp. 1750114 ◽  
Author(s):  
Shince. V. Joseph ◽  
S. C. Mohanty

Free vibration analysis of a sandwich plate with viscoelastic material core and functionally graded material (FGM) constraining layer under centrifugal force field is investigated herein. One edge of the sandwich plate is fixed to a rotating hub. The first-order shear deformation theory (FSDT) is used in the finite element modeling of the problem. The effects of strains due to the longitudinal and transverse deformations are also considered in addition to the shear deformation of the core. Various parametric studies are carried out to examine the effects of volume fraction index, setting angle, hub radius and rotational speed on the vibration characteristics of the sandwich plate. It is found that the fundamental frequency of the plate decreases with an increase in the volume fraction index of the FGM layer, viscoelastic core thickness and setting angle. The first mode loss factor increases with respect to the increasing volume fraction index. Increase in rotational speed and hub radius lead to an increase in the natural frequencies and a decrease in the modal loss factors.


2021 ◽  
pp. 107754632110131
Author(s):  
YX Hao ◽  
MX Wang ◽  
W Zhang ◽  
LT Liu ◽  
SW Yang

In this article, the natural vibration investigation of a functionally graded material sandwich plate with initial geometrical imperfection of the exponential function is conducted. Two face sheets of the sandwich plate are composited by functionally graded material. Their material coefficients are affected by temperature and vary in the direction of thickness following the power law. The core layer is only the metal. With the aid of Reddy’s displacement fields, a quasi-three-dimensional model is used, in which the effects of transverse stretching on natural vibration are considered. The natural frequencies and model shapes of the system are calculated on the basis of Rayleigh–Ritz method and Chebyshev polynomials. A comparison of these results with those of the existing three-dimensional theory results shows the validity and computability of present method. The influences of various parameters on the natural frequencies are researched in detail.


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