“…Therefore, the so-called MDGKN system (M, D, G, K, and N indicate the system inertia, dissipation, gyroscopic, potential and circulatory terms) was presented and investigated. Correspondingly, Volodymyr investigated the double pendulum flutter instability characteristics with arbitrary mass, stiffness and imperfect follower type loading by using Routh-Hurwitz criteria, and found the stiffness ratio induced destabilizing influences, but neglecting arbitrary mass induced destabilizing influences [1,22]. As from the experimental observation perspectives, although Koiter has noted that the "unrealistic follower forces" can not be directly achieved and exerted on the pendulum end, Bigoni et al have developed a significant breakthrough of the experimental devices, i.e.…”