“…Using Mathieu-type equations to model auto-parametric resonance [Tagata, 1977;Uhrig, 1993] also capture coupling between the in-plane and out-of-plane modes of vibration [Fujino et al, 1993;Gattulli et al, 2005Gattulli et al, , 2004. The loss of stability of the semi-trivial solution, for which the response is limited to just the directly excited mode, has also been studied in detail [Berlioz &Lamarque, 2005;Gonzalez-Buelga et al, 2008;Macdonald et al, 2010;Rega, 2004a,b;Rega et al, 1999]. Experimental analysis of the cable response in out-of-plane modes due to vertical excitation have been reported in [Rega et al, 1997;Rega & Alaggio, 2009;Rega et al, 2008].…”