Vibration and stability of laminated composite orthogrid plates

Abstract

Generally, a grid layer is used as an orthotropic layer to reinforce plates and shells or as an independent structural element. The proposed laminated grid plate is composed of different grid layers with different orientations. Consequently, the grid layers with different fibers, patterns and orientations can be used, resulting in laminates with enhanced stiffness and coupling effects. In the present study, to investigate the efficiency of the laminated grids, the vibration and buckling responses of a conventional and laminated grid plates are compared. The first-order shear deformation plate theory along with Ritz method is used to obtain the buckling load and natural frequencies of the plates. The effectiveness of increasing the number of layers on mechanical responses of the laminated grids is also studied. The analytical results of vibration frequencies are compared and validated by finite element method and experimental analysis of two manufactured grid plates. The results indicate that thoughtful selection of stacking sequences of the laminated grids considerably enhances the response of the laminated grids in comparison with conventional grids.

Influence of employing laminated isogrid configuration on mechanical behavior of grid structures

“…Where [K] and [K G ] are the elastic and geometric stiffness matrices, andd is the vector of coefficients (W mn , R mn and S mn ) that can be presented as below 18 :…”

“…Achieving the λ from Equation (20), the buckling loads can be calculated. To calculate the free vibration frequencies, the energy function of the plate's vibration based on FSDT can be presented as 18 :…”

“…[9][10][11][12][13][14][15][16][17] . E hsani a nd Rezaeepazhand 18 presented a new class of grid structures which are known as "laminated grid structures". They investigated lamination effects on stiffness and mechanical behavior of grid structures.…”

Application of Laminated Composite Grids as a Reinforcing Element for Automotive Components

“…They investigated lamination effects on stiffness and mechanical behavior of grid structures. Ehsani et al [7,8] studied the influence of the stacking sequence and pattern composition on buckling load of laminated composite grid plates and also conducted studies on the buckling load and natural vibration of laminated orthogrid plates. Their results showed that, there are proper stacking sequences, which considerably improves the mechanical behaviors of the grid structures.…”

“…Despite the many studies on different types of grid structures there have been rare investigations on the applications of laminated grid structures. Similar to a laminated composite, laminated grid is composed of different grid layers with different orientations, which can improve the stiffness and coupling effects of conventional grids [8]. Tailored stiffness of a structure is achieved by employing full anisotropic properties of a laminated grid compare to orthotropic properties with at most in plane anisotropic of a corresponding conventional grid [6].…”