Elastic Stability of Shallow Bending-Active Arches

We present a numerical and experimental investigation on the nonlinear equilibrium paths and elastic stability of pinned shallow arches realized by buckling a straight strut and then subjected to a transverse central point load. Finite element analyses were run to compare the behavior of arches with and without initial pre-stress condition. The effects of initial shallowness ratio, axial-to-bending stiffness ratio, and initial geometric imperfections on the equilibrium path and bifurcation points were investigated. As an experimental verification, laboratory tests were conducted on a pinned-pinned shallow arch obtained by buckling a thin, slender steel bar. Static and dynamic measurements were carried out to determine the load-displacement curve, the subsequent static deformed configurations, the frequency-load curves, and the buckling load. The acquired data were used for buckling load predictions and to obtain stability domains in terms of form factors and imperfection-sensitivity parameters.