Dynamic load-absorbing materials and articles

A double-shell helmet, comprising:nan outer shell;an impact absorbing material layer affixed to the outer shell on a first side of the impact absorbing material layer, the impact absorbing material layer includingna matrix material including at least three sizes of stress-concentrating features and further including:a plurality of first features having a first average characteristic dimension of between ten microns and two hundred microns,a plurality of second features having a second average characteristic dimension that is at least one order of magnitude larger than said first average characteristic dimension, anda plurality of third features having a third average characteristic dimension that is at least one order of magnitude larger than said second average characteristic dimension,wherein the material proximate to said first, second, and third features progressively buckles upon application of a load, such that material proximate said third features tends to deform before the deformation of material proximate to said second and first features, and material proximate said first features tends to deform after the deformation of material proximate to said second and third features;an inner shell affixed to the impact absorbing material layer on a second side of the impact absorbing material layer opposite the first side of the impact absorbing material layer; anda foam layer affixed to the inner shell.