“…As early as 1960s, the classical Rayleigh-Ritz method, finite difference method, variational method, Galerkin method, series expansion method and integral equation method were introduced by Leissa (1969) in detail. Since then, many numerical methods have appeared one after another, among which the commonly used numerical methods include finite element method (Kanaka Raju and Venkateswara Rao, 1976), Rayleigh-Ritz method using characteristic orthogonal polynomial (Bhat, 1985), a modified method of the classical initial value technique (Al-Khaiat, 1989), extended Kantorovich method (Kumari and Behera, 2017), element-free Galerkin method (Bahmyari and Rahbar-Ranji, 2012) and isogeometric analysis method (Valizadeh et al, 2013). Compared with numerical methods, the research on analytical methods of this kind of problems is much less.…”