Javad Bagheri-Marzi - MSc, School of Mechanical Engineering, Babol Nooshirvani Univerity of Technology, Shariati Av., ۴۷۱۴۸-۷۱۱۶۷ Babol, Mazandaran, Iran.
Ramazan-Ali Ramazan-Ali - Associate Professor, School of Mechanical Engineering, Babol Nooshirvani Univerity of Technology, Shariati Av., ۴۷۱۴۸-۷۱۱۶۷ Babol, Mazandaran, Iran.
Paolo S. Valvo - Associate Professor, Department of Civil and Industrial Engineering, University of Pisa, Largo Lucio Lazzarino, I-۵۶۱۲۲ Pisa, Italy
Maryam Abedi - Assistant Professor, Department of Mechanical Engineering, Faculty of Engineering and Technology, University of Mazandaran, Babolsar, Iran.
Saman Sadripour - PhD Student, School of Mechanical Engineering, Babol Nooshirvani Univerity of Technolo-gy, Shariati Av., ۴۷۱۴۸-۷۱۱۶۷ Babol, Mazandaran, Iran.

In this paper, the undamped free vibration analysis of arbitrary shaped laminated composite plates with general stacking sequences is conducted based on the first-order shear defor-mation theory. The finite element method is used to obtain the plate's vibrational characteris-tics by introducing a six-nodded triangular element, i.e., natural frequencies and the corre-sponding mode shapes. The element considered is a higher-order triangular element. Each node includes five degrees of freedom. Gaussian numerical integration is used to calculate the mass and stiffness matrices. The whole solution method is implemented within the MATLAB. The convergence of the results has been investigated, and results have been com-pared against some available data in the literature and also commercial software ANSYS in which three-dimensional analysis is used. Excellent agreements have been observed. The ef-fects of several parameters – such as boundary conditions, geometry, and lay-ups – on the natural frequencies are studied in detail

Free Vibration; Arbitrary Shape, Laminated Composite; Plate; Finite Element.