Microlattice layers
A three-dimensional microlattice layer comprising a plurality of interconnected filaments extending along at least three different directions from a plurality of nodes. The microlattice layer may further comprise at least one material layer extending laterally between and interconnecting at least two or more nodes. The at least one material layer may be configured to transversely and rotationally constrain the nodes to increase the overall compressive strength and stiffness of the microlattice structure. The at least one material layer may comprise a single, continuous layer and/or a plurality of material layer segments. The microlattice layer may comprise a single, continuous layer or a plurality of microlattice layer segments. The microlattice layer may be stacked, the stacked microlattice layers may further comprise one or more material layers and/or one or more impact mitigation layers.
1. An impact mitigation structure, comprising:
at least one three-dimensional (3D) microlattice structure formed using a 3D printing device;
the at least one 3D microlattice structure comprising a plurality of filaments that are straight and extend obliquely from a first end at a first surface to a second end at a second surface, wherein:
the first end of each filament of an interior subset of the plurality of filaments connects with the first end of at least two other filaments of the plurality of filaments to form a first set of end nodes at the first surface;
the second end of each filament of the interior subset of the plurality of filaments connects with the second end of at least two other filaments to form a second set of end nodes at the second surface;
each filament of the interior subset of the plurality of filaments intersects with at least two other filaments of the interior subset to form a respective first mid node of a set of first mid nodes between the first surface and the second surface, wherein the set of first mid nodes are not laterally interconnected to other mid nodes of the set of first mid nodes;
each filament of the interior subset of the plurality of filaments intersects with at least two other filaments of the interior subset to form a respective second mid node of a set of second mid nodes between the first surface and the second surface; and
a first material layer extends across a portion of the at least one 3D microlattice structure, the first material layer contacting the first set of end nodes and the first material layer comprising a plurality of segments laterally interconnecting respective end nodes of the first set of end nodes with at least two other end nodes of the first set of end nodes at the first surface, wherein the segments are spaced apart and form a repeating array.
2. The impact mitigation structure of claim 1 , wherein:
each end node in the first set of end nodes is directly connected to another end node in the first set of end nodes by a first connecting member; and
each end node in the second set of end nodes is directly connected to another end node in the second set of end nodes by a second connecting member.
3. The impact mitigation structure of claim 1 , wherein each filament in the plurality of filaments has a cross-section area between 2 and 8 square millimeters.
4. The impact mitigation structure of claim 1 , wherein the first material layer comprises a plurality of perforations.
5. The impact mitigation structure of claim 1 , wherein the plurality of filaments comprising an aspect ratio of 3:1 or greater.
6. The impact mitigation structure of claim 3 , wherein the cross-section area is solid.
7. The impact mitigation structure of claim 1 , wherein the first surface is custom-fitted to a shape of a wearer's head.
8. A helmet, comprising:
a shell; and
an impact mitigation structure coupled to the shell, comprising:
at least one three-dimensional (3D) microlattice structure formed using a 3D printing device, the at least one 3D microlattice structure comprising a plurality of filaments that are straight and extend obliquely from a first end at a first surface to a second end at a second surface, wherein:
the first end of each filament of an interior subset of the plurality of filaments connects with a respective end of at least two other filaments to form a first set of end nodes at the first surface;
the second end of each filament of the interior subset of the plurality of filaments connects with a respective end of at least two other filaments to form a second set of end nodes at the second surface;
each filament of the interior subset of the plurality of filaments intersects with at least two other filaments of the interior subset to form a respective first mid node of a set of first mid nodes between the first surface and the second surface, wherein the set of first mid nodes are not laterally interconnected to other mid nodes of the set of first mid nodes; and
each filament of the interior subset of the plurality of filaments intersects with at least two other filaments of the interior subset to form a respective second mid node of a set of second mid nodes between the first surface and the second surface; and
a first material layer extends across a portion of the at least one 3D microlattice structure, the first material layer contacting the first set of end nodes and the first material layer comprising a repeating array of openings and segments laterally interconnecting respective end nodes of the first set of end nodes with at least two other end nodes of the first set of end nodes at the first surface.
9. The helmet of claim 8 , wherein:
each end node in the first set of end nodes is directly connected to another end node in the first set of end nodes by a first connecting member; and
each end node in the second set of end nodes is directly connected to another end node in the second set of end nodes by a second connecting member.
10. The helmet of claim 8 , wherein the first material layer comprises a plurality of perforations.
11. The helmet of claim 8 , further comprising a pad contoured to fit a shape of a head, wherein the pad comprises the impact mitigation structure.
12. The helmet of claim 8 , wherein the at least one 3D microlattice structure buckles when impacted.
13. The helmet of claim 8 , wherein the set of second mid nodes are not laterally interconnected to other mid nodes of the set of second mid nodes.
14. The helmet of claim 8 , further comprising a foam liner between the impact mitigation structure and a head of a wearer.
15. The helmet of claim 14 , wherein:
the first surface is contoured based on the head of the wearer; and
the second surface is contoured to a curved interior surface of the shell of the helmet.
16. A pad for a helmet, the pad comprising:
a microlattice structure comprising a plurality of filaments that are straight and extend obliquely between a first end at a first surface and a second end at a second surface, wherein:
the first end of each filament of an interior subset of the plurality of filaments connects with a respective end of at least two other filaments of the plurality of filaments to form a first set of end nodes at the first surface;
the second end of each filament of the interior subset of the plurality of filaments connects with a respective end of at least two other filaments to form a second set of end nodes at the second surface;
each filament of the interior subset of the plurality of filaments intersects with at least two other filaments of the interior subset to form a respective first mid node of a set of first mid nodes between the first surface and the second surface;
the set of first mid nodes are not laterally interconnected to other mid nodes of the set of first mid nodes;
each filament of the interior subset of the plurality of filaments intersects with at least two other filaments of the interior subset to form a respective second mid node of a set of second mid nodes between the first surface and the second surface; and
a first material layer comprising an open structure including a repeating array of segments laterally interconnecting respective end nodes of the first set of end nodes with at least two other end nodes of the first set of end nodes at the first surface.
17. The pad of claim 16 , wherein the set of second mid nodes are not laterally interconnected to other mid nodes of the set of second mid nodes.
18. The pad of claim 16 , wherein the first surface is custom manufactured based on a head of a wearer.
19. The pad of claim 18 , wherein the second surface is contoured to a curved interior surface of a shell of the helmet.