Bending Analysis of SMA Embedded Rectangular Laminated Sandwich Plates with Soft Core Using 3D Finite Element Method

2011 ◽  
Vol 110-116 ◽  
pp. 1458-1465 ◽  
Author(s):  
M. Khadem ◽  
M. M. Kheirikhah
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Transverse Shear ◽  
Soft Core ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
3D Finite Element ◽  
Bending Analysis ◽  
Transverse Shear Stresses ◽  
3D Finite Element Method

Nowadays Shape Memory Alloys (SMAs) are used as actuators in many applications such as aerospace structures. In sandwich structures, the SMA wires or plates are used in the skins for shape control of the structure or vibration damping. In this paper, bending behavior of sandwich plates with embedded SMA wires in their skins is studied. 3D finite element method is used for construction and analysis of the sandwich plate with a flexible core and two stiff skins. Some important points such as continuity conditions of the displacements, satisfaction of interlaminar transverse shear stresses, the conditions of zero transverse shear stresses on the upper and lower surfaces and in-plane and transverse flexibility of soft core are considered for accurate modeling and analysis of sandwich structures. Solution for bending analysis of sandwich plates under various transverse loads are presented and the effect of many parameters such as plate dimensions, loading conditions, material properties of core, skins and SMA wires are studied. Comparison of the present results in special case with those of the three-dimensional theory of elasticity and some plate theories confirms the accuracy of the proposed model.

Bending Analysis of Composite Sandwich Plates with Flexible Core Using 3D Finite Element Method

2011 ◽  
Vol 110-116 ◽  
pp. 1229-1236
Author(s):  
Mohammad Mahdi Kheirikhah ◽  
Seyyed Mohammad Reza Khalili
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Transverse Shear ◽  
Sandwich Plate ◽  
Element Model ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
Normal Strain ◽  
Bending Analysis ◽  
Transverse Shear Stresses

Sandwich plates have been extensively used in many engineering applications such as automotive and aerospace. In the present paper, an accurate finite element model is presented for bending analysis of soft-core rectangular sandwich plates. The sandwich plate is composed of three layers: top and bottom skins and core layer. The core is assumed as a soft orthotropic material and skins are assumed generally unequal laminated composites. Finite element model of the problem has been constructed in the ANSYS 11.0 standard code area. Continuity conditions of transverse shear stresses at the interfaces are satisfied as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of plate. Also transverse flexibility and transverse normal strain and stress of core are considered. The effect of geometrical parameters of the sandwich plate are studied. Comparison of the present results with those of plate theories confirms the accuracy of the proposed model.

An accurate zigzag theory for bending and buckling analysis of thick laminated sandwich plates with soft core

2020 ◽  
Vol 54 (18) ◽  
pp. 2473-2488
Author(s):  
Qilin Jin ◽  
Weian Yao
Keyword(s):  
Transverse Shear ◽  
Buckling Analysis ◽  
Soft Core ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
Plate Element ◽  
Proposed Model ◽  
Transverse Shear Stresses ◽  
Zigzag Theory ◽  
Benchmark Solutions

An accurate and computationally attractive zigzag theory is developed for bending and buckling analysis of thick laminated soft core sandwich plates. The kinematic assumptions of the proposed zigzag theory are obtained by superimposing a nonlinear zigzag function on the first-order shear deformation theory. In order to obtain the accurate transverse shear stresses, a preprocessing approach based on the three-dimensional equilibrium equations and the Reissner mixed variational theorem is used. It is significant that the second-order derivatives of in-plane displacement variables have been removed from the transverse shear stresses, such that the finite element implementation is greatly simplified. Thus, based on the proposed zigzag model, a computationally efficient four-node C0 quadrilateral plate element with linear interpolation function is proposed for bending and buckling analysis of soft core sandwich plates. The advantage of the present formulation is that no post-processing approach is needed to calculate the transverse shear stresses while maintaining the computational accuracy of a linear plate element. Moreover, the accurate transverse shear stresses can be involved in the strain energy which can actively improve the accuracy of critical loads. Performance of the proposed model is assessed by comparing with several benchmark solutions. Agreement between the present results and the reference solutions is very good, and the proposed model only includes the seven displacement variables which can demonstrate the accuracy and effectiveness of the proposed model.

A C0 three-node triangular element based on preprocessing approach for thick sandwich plates

2017 ◽  
Vol 21 (6) ◽  
pp. 1820-1842
Author(s):  
Wu Zhen ◽  
Ma Rui ◽  
Chen Wanji
Keyword(s):  
Transverse Shear ◽  
Equilibrium Equation ◽  
Three Dimensional ◽  
Higher Order ◽  
Triangular Element ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
Transverse Shear Stress ◽  
Transverse Shear Stresses ◽  
Derivatives Of

This paper will try to overcome two difficulties encountered by the C0 three-node triangular element based on the displacement-based higher-order models. They are (i) transverse shear stresses computed from constitutive equations vanish at the clamped edges, and (ii) it is difficult to accurately produce the transverse shear stresses even using the integration of the three-dimensional equilibrium equation. Invalidation of the equilibrium equation approach ought to attribute to the higher-order derivations of displacement parameters involved in transverse shear stress components after integrating three-dimensional equilibrium equation. Thus, the higher-order derivatives of displacement parameters will be taken out from transverse shear stress field by using the three-field Hu–Washizu variational principle before the finite element procedure is implemented. Therefore, such method is named as the preprocessing method for transverse shear stresses in present work. Because the higher-order derivatives of displacement parameters have been eliminated, a C0 three-node triangular element based on the higher-order zig-zag theory can be presented by using the linear interpolation function. Performance of the proposed element is numerically evaluated by analyzing multilayered sandwich plates with different loading conditions, lamination sequences, material constants and boundary conditions, and it can be found that the present model works well in the finite element framework.

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