Experiments on Probing the Configuration Space of Post-Buckled Panels

This paper describes a primarily experimental study in which a nonlinear structural component (a slender, mechanically buckled panel) is subject to probing. That is, equilibrium configurations are explored when a specific location on the panel is subject to the application of a (variable) displacement constraint and characterized by a corresponding probe force. This probe force (in this study located at the center of the rectangular panels) is measured using a load cell and the resulting shape(s), taken up by the panel, measured using digital image correlation (DIC). Although the probe is only applied at a single location, this arrangement supplies considerable information about the changing equilibrium landscape including revealing co-existing equilibrium configurations using large perturbations and associated hysteresis phenomena. In addition, monitoring the probing force, and specifically when it drops to zero, provides a window into “free” equilibria that would otherwise be unstable and unobservable. Finally, it is shown that the probed equilibrium configurations provide the “landscape” within which any dynamically induced trajectories evolve including snap-through oscillations.