Protective headgear with integrally-formed layer

A helmet configured to be worn on a head of a wearer, the head having a shape and a contour, said helmet comprising:

• a plurality of layers coupled together including an energy management layer and an outer shell layer disposed over the energy management layer,
• wherein the energy management layer comprises an integral structure formed by additive manufacturing and comprising closed cells, in which a size of the closed cells varies spatially within the helmet to absorb and dissipate energy received by the helmet during an impact by an external force, the size of the closed cells being smaller closer to the outer shell layer and larger further from the outer shell layer, wherein the size of the closed cells forming the integral structure are formed in a pattern that is the same shape and varies in the size from a front to a back of the helmet or from a side to side of the helmet,
• wherein the outer shell layer is configured to disperse and dissipate impact energy from the external force, and
• wherein each of the plurality of layers has a density and a geometry, and wherein the density or the geometry of at least one layer differs from the density or the geometry of at least another layer.