Energy absorbing truss structures for mitigation of injuries from blasts and impacts
Architected materials with superior energy absorption properties when loaded in compression. In several embodiments such materials are formed from micro-truss structures composed of interpenetrating tubes in a volume between a first surface and a second surface. The stress-strain response of these structures, for compressive loads applied to the two surfaces, is tailored by arranging for some but not all of the tubes to extend to both surfaces, adjusting the number of layers of repeated unit cells in the structure, arranging for the nodes to be offset from alignment along lines normal to the surfaces, or including multiple interlocking micro-truss structures.
1. A system for protection from impulsive loads as generated by impacts and explosions, the system comprising a first micro-truss architecture, wherein the first micro-truss architecture comprises:
a first surface and a second surface parallel to each other with a distance therebetween defining a thickness of the first micro-truss architecture;
a plurality of angled struts extending along a plurality of non-vertical directions each having a first end on the first surface and a second end;
a plurality of nodes where the plurality of angled struts extending along a plurality of directions interpenetrate one another;
the plurality of angled struts and the plurality of nodes defining a plurality of unit cells each having an upper node among the plurality of nodes, a lower node among the plurality of nodes, and a cell height, the cell height being the distance between the upper node and the lower node, wherein the second end of each of the angled struts is on the lower node closest to the second surface at a distance away from the second surface; and
a post extending from the first surface in a direction perpendicular to the first surface, having a first end on the first surface and a second end extending past the lower node closest to the second surface onto the second surface, the post being a single straight rod.
2. The system of claim 1 , wherein there is only one layer of unit cells between the first surface and the second surface.
3. The system of claim 1 , wherein there are at least two layers of unit cells between the first surface and the second surface.
4. The system of claim 1 , wherein the first micro-truss architecture is made of a material selected from the group consisting of magnesium, aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, alloys thereof, polycarbonate, aramid, high impact polystyrene, nylon, ultra-high molecular weight polyethylene, poly(p-xylylene), and combinations thereof.
5. The system of claim 1 , wherein the system is a part of a foot pad or floor mat inside a vehicle.
6. The system of claim 1 , wherein the first micro-truss architecture further comprises a face sheet on the first surface, wherein the face sheet is configured to aid in shock absorption.
7. The system of claim 1 , wherein the first micro-truss architecture further comprises a face sheet on the first surface, wherein the face sheet comprises a material selected from a group consisting of polymer, rubber, metal, and combinations thereof.
8. The system of claim 1 , wherein the rod is hollow.