Abstract—In this paper, natural frequencies of the sandwich plates with embedded shape memory alloy (SMA) wires in their face sheets is obtained. Three-Dimensional (3D) finite element method (FEM) is used for constructing and analyzing of the sandwich plates with flexible core and two stiff face sheets. Natural frequencies of the sandwich plates are presented and the effects of plate dimensions and boundary conditions of the sandwich plate are studied. According to the obtained results, the natural frequencies of the sandwich plate were improved by employing the SMA wires in the face sheets. Keywords—Finite Element Method, Natural Frequencies, SMA wires, Sandwich Plate. I. INTRODUCTION IGH strength-to-weight ratio and good energy absorbing of composite sandwich plates have been caused that they are widely used in various engineering applications such as building structures and aerospace. Sandwich plates are generally consisted of two thin high strength face sheets and a soft thick low strength core which are adhesively bonded together. In most cases, the core consisted of a foam polymer or honeycomb material, while composite laminates are commonly used as the face sheets. To use these structures efficiently, an excellent understanding of their dynamical behavior is needed. To date, there are many papers have been published by researchers about vibrational analysis and dynamical behavior of sandwich plates. The first-order shear deformation theory was developed by Wang [1] for vibration analysis of sandwich plates, but the accuracy of solutions of this theory is strongly dependent on the shear correction factors. Kant and Swaminathan [2] and Matsunaga [3] presented the analytical solution for natural vibration analysis of sandwich plates using a high-order ESL theory. Als, based on Reddy’s higher-order theory, a finite element model was proposed by Nayak [4]. To model the thick sandwich plates in a better manner and to evaluate their local behaviors, some developed higher order mixed layerwise plate theories were used for vibration analysis Mohammad Mahdi Kheirikhah is with the Faculty of Industrial and Mechanical Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran (corresponding author’s phone: +9828133670051; e-mail: kheirikhah@qiau.ac.ir). Hasan Aghabarati, is with the Faculty of civil Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran (e-mail: aghabarati@qiau.ac.ir). Poone Khosravi is with the Faculty of Engineering, Kowsar educational Institute, Qazvin, Iran (e-mail: poone.khosravi@gmail.com). by Carrera [5] and Rao and Desai [6]. In these models, the number of unknowns depends on the number of the layers in composite and it becomes large as the number of the layers increases. In order to overcome the high computational times in the layer-wise theories, zigzag theories with linear or high- order local functions were proposed. Di Suiva [7] proposed a refined zigzag plate theory in which the unknowns for the in- plane displacements at each layer were assumed in terms of those at the reference plane and the transverse displacement was assumed constant along the plate thickness. A third-order zigzag plate theory was proposed by Kapuria and Achary [8] for sandwich plates. Ganapathi et al. [9] analyzed the nonlinear dynamic behavior of the sandwich plates using a third-order zigzag theory. Also, free vibration analysis of sandwich panels with a flexible core based on the high-order sandwich panel theory (HSAPT) were presented by Frostig and Thomsen [10]. Based on third-order global-local plate theory (GLPT), Zhen and Wanji [11] and Shariyat [12] studied free vibration analysis of sandwich plates. To date, regardless of the above theories which were presented to analyze the mechanical behavior of the sandwich and composite structures, many researchers studied the static and dynamic responses of the SMA fiber-reinforced composite plates. SMAs are used as smart actuators in many applications such as aerospace, robotic and medical. Embedding SMA wires in the face sheets of the sandwich structures bring so many advantages. In sandwich structures, the SMA wires or plates are used in the face sheets for the shape control of the structure or vibration damping. Also, SMA wires have the ability to generate recovery tensile stress which reduces the in- plane stress and strain components. They can also be actuated by electrical signal or heat flow which causes to control the shape of the structure and this is because of their ability to remember their predefined shape [13]. Yao Kuo et al. [13] inspected the effect of embedding SMA wires on the buckling behavior of laminated composite plates using finite element method. Ostachowicz [14] illustrated the influence of the SMA wires on the natural frequencies and thermal buckling of a multilayer composite plate using finite element method. The stress-strain relationships also were presented for a single composite lamina with embedded shape memory materials. Yan Tsai [15] studied the dynamic stability of a Nitinol fiber-reinforced composite beam under periodic dynamic force. Natural frequencies and static bucking loads were investigated using Finite element method and harmonic Natural Vibration Analysis of Sandwich Plates with Embedded SMA Wires Mohammad Mahdi Kheirikhah, Hasan Aghabarati, and Poone Khosravi H 2nd International Conference on Innovations in Engineering and Technology (ICCET’2014) Sept. 19-20, 2014 Penang (Malaysia) http://dx.doi.org/10.15242/IIE.E0914014 67