“…Functionally graded materials (FGMs) have proved to be more benefit in comparison with the laminate composites and found widespread application in the high-tech industries such as aerospace, automobile, electronics, optics, chemistry, biomedical engineering etc,... For vibration analysis of FGM structures, a number of methods have been proposed such as analytical (Nguyen, Vo, Nguyen, & Lee, 2016;Sina, Navazi, & Haddadpour, 2009), Rayleigh-Ritz method (Pradhan & Chakraverty, 2013), Galerkin (Sheng & Wang, 2018), combined Fourier series -Galerkin method (Zhu & Sankar, 2004), differential quadrature method (DQM) (Sundaramoorthy Rajasekaran, 2013a;Sınır, Çevik, & Sınır, 2018;Tang, Lv, & Yang, 2019), perturbation method (Sınır et al, 2018), asymptotic development method (Cao, Gao, Yao, & Zhang, 2018), discrete singular convolution and Taylor series expansion method (Wang & Yuan, 2017). While the aforementioned methods are limited to apply for analysis of simple FGM beam structures, the Finite Element Method (FEM) developed in (Alshorbagy, Eltaher, & Mahmoud, 2011;Eltaher, Abdelrahman, Al-Nabawy, Khater, & Mansour, 2014;Mashat, Carrera, Zenkour, Al Khateeb, & Filippi, 2014;Naccache & El Fatmi, 2018) could be used for more complex structures such as that are composed from different beam elements.…”