Coulais, CorentinOvervelde, JohannesLubbers, Luuk A.Bertoldi, Katiavan Hecke, Martin2016-07-142015Coulais, Corentin, Johannes T. B. Overvelde, Luuk A. Lubbers, Katia Bertoldi, and Martin van Hecke. 2015. “Discontinuous Buckling of Wide Beams and Metabeams.” Physical Review Letters 115 (4) (July 21). doi:10.1103/physrevlett.115.044301.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:27662697We uncover how nonlinearities dramatically alter the buckling of elastic beams. First, we show experimentally that sufficiently wide ordinary elastic beams and specifically designed metabeams ---beams made from a mechanical metamaterial--- exhibit discontinuous buckling, an unstable form of buckling where the post-buckling stiffness is negative. Then we use simulations to uncover the crucial role of nonlinearities, and show that beams made from increasingly nonlinear materials exhibit increasingly negative post-buckling slope. Finally, we demonstrate that for sufficiently strong nonlinearity, we can observe discontinuous buckling for metabeams as slender as 1% numerically and 5% experimentally.en-USJournal Article2016-07-1410.1103/PhysRevLett.115.044301