“…Great efforts have been made to develop various sophisticated theories and approaches to tackle the nonlinear problems, such as the time domain methods including the perturbation method [47,48], multiple scale method [49], KBM method [50], etc. and the frequency domain methods including the Generalized Frequency Response Function (GFRF) [41,45,51,52], the Nonlinear Output Frequency Response Function (NOFRF) [33,34,[53][54][55], the Describing Function Method [56] and the harmonic balance method [36,57], etc. There are a great number of literatures available about the nonlinear system analysis using above methods, and most of them are focused on investigating how the nonlinear characteristic parameters k n k L-1 k 1…”