“…Harmonic balance method (Mickens, 1986;Lim et al, 2005;Belendez et al, 2006;Wu et al, 2006;Mickens, 2007;Alam et al, 2007;Belendez et al, 2009;Lai et al, 2009;Hosen et al, 2012) is a powerful method in which truncated Fourier series is used. Iterative homotopy harmonic balance (Guo and Leung, 2010), differential transformation (Ghafoori et al, 2011) and max-min (Yazdi et al, 2012) methods have been developed for solving strongly nonlinear oscillators. Energy balance method (He, 2002;Khan and Mirzabeigy, 2014;Alam et al, 2016;Mehdipour et al, 2010;Ebru et al, 2016;Zhang et al, 2009) is another widely used technique for solving strongly nonlinear oscillators.…”