Abstract: A helmet including an insert provides the ability of including a highly energy absorbing feature within the insert. The insert includes a structure such as a Bingham plastic which, upon impact, absorbs the energy of the impact by converting from a solid to a liquid. Other energy absorbing features are contemplated. The energy absorption process occurs in one aspect in a nonreversible manner such that once a high enough level impact occurs on the insert, it must be replaced within the helmet. The insert has a fastener which enables it to be replaceable. In this manner, a highly absorbing feature of a helmet can be provided to reduce concussions while not requiring the complete replacement of a helmet.

Abstract: A helmet including an insert provides the ability of including a highly energy absorbing feature within the insert. The insert includes a structure such as a Bingham plastic which, upon impact, absorbs the energy of the impact by converting from a solid to a liquid. Other energy absorbing features are contemplated. The energy absorption process occurs in one aspect in a nonreversible manner such that once a high enough level impact occurs on the insert, it must be replaced within the helmet. The insert has a fastener which enables it to b replaceable. In this manner, a highly absorbing feature of a helmet can be provided to reduce concussions while not requiring the complete replacement of a helmet.

Abstract: Disclosed herein is a composite structure for deflecting and spreading kinetic energy transmission after various types of impacts utilizing foam structures having graded properties. The structure has a first composite layer, composed of a discrete reinforcement and a continuous binder. The helmet receives contact of an object that transfers kinetic energy to a first composite layer. The helmet uses a second composite layer adjacent to the first composite layer designed such that the second composite layer compresses and expands into an expansion zone in the second composite layer. The second composite layer has expansion structures with a graded modulus such that the material at the tip of an expansion structure has a low modulus and the modulus in the expansion structure increases as it moves from the tip to the base of the expansion structure.