Surprising Instabilities of Simple Elastic Structures

Examples of structures buckling in tension are presented, where no compressed elements are present, slightly different from those previously proposed by the authors. These simple structures exhibit interesting postcritical behaviours, for instance, multiple configurations of vanishing external force are evidenced in one case. Flutter instability as induced by dry friction is also considered in the Ziegler pendulum, with the same arrangement introduced by Bigoni and Noselli (2011), but considering now the dynamical effects due to the mass of the wheel, which was previously neglected. It is shown that, for the values of rotational inertia pertinent to our experimental set-up, this effect does not change the overall behaviour, so that previous results remain fully confirmed.