Lofted lattice structures and methods of making the same
An additively manufactured lattice includes a plurality of symmetrically oriented repeating unit cells. Each of the unit cells is comprised of a vertically oriented tubular structure having a top edge and bottom edge, said tubular structure defined by a circumferential side wall extending from said top edge to said bottom edge. The side wall has a lower portion, an intermediate portion, and an upper portion, with the lower portion terminating at the bottom edge, the upper portion terminating at the top edge, and the intermediate portion positioned between the lower portion and the upper portion. A plurality of spaced legs is included with each unit cell, with each leg formed as an outfolding of the side wall, each outfolding beginning at the side wall intermediate portion and extending progressively further outward through the side wall lower portion to the bottom edge.
1. An additively manufactured lattice comprising:
a plurality of symmetrically oriented repeating unit cells, each of said unit cells comprising a vertically oriented tubular structure having a top edge and bottom edge, said tubular structure defined by a circumferential side wall extending from said top edge to said bottom edge,
said side wall having a lower portion, an intermediate portion, and an upper portion, said lower portion terminating at said bottom edge and said upper portion terminating at said top edge; and
a plurality of symmetrically spaced legs, each leg formed as an outfolding of said side wall, each outfolding beginning at said side wall intermediate portion and extending progressively further outward through said side wall lower portion to said bottom edge,
wherein said side wall further comprises a plurality of symmetrically spaced infoldings, with an infolding between each said outfolding,
with said outfoldings defining external vertices and said infolding defining internal vertices,
and with a plurality of said external vertices of each unit cell nested into internal vertices of adjacent unit cells.
2. The lattice of claim 1 , wherein said side walls of adjacent unit cells in said lattice are at least partially merged with or interconnected with one another.
3. The lattice of claim 1 , wherein said symmetrically spaced legs of adjacent unit cells in said lattice are at least partially, or completely, nested between one another.
4. The lattice of claim 1 , wherein said symmetrically spaced legs are configured as a plurality of circumferential, outwardly tapering, undulations in said side wall lower portion.
5. The lattice of claim 1 , wherein said tubular structure upper portion has a cross-sectional configuration that is circular, oval, or polygonal.
6. The lattice of claim 1 , wherein said plurality of symmetrically spaced legs comprises three symmetrically spaced legs.
7. The lattice of claim 1 , wherein said lattice comprises a planar portion, a curved portion, or a combination thereof.
8. The lattice of claim 7 , wherein said curved portion is present, and said unit cells of said curved portion comprise conformal unit cells.
9. The lattice of claim 1 , wherein said side wall has a plurality of perforations therein.
10. The lattice of claim 1 , wherein said side wall comprises a buckling wall having a progressively graded buckling response from said upper portion through said intermediate portion to said lower portion.
11. The lattice of claim 1 , wherein said legs are configured to disperse impact force received on a top edge thereof across a greater surface area of an adjacent or underlying structure, and/or provide channels for energy dissipation or dispersion of that force.
12. A wearable garment, helmet or footwear article having an impact absorbing protective pad therein, said protective pad comprising a lattice of claim 1 .
13. A lattice comprising:
a first lattice layer and a second lattice layer, each of said first and second lattice layers comprising:
a plurality of symmetrically oriented repeating unit cells, each of said unit cells comprising a vertically oriented tubular structure having a top edge and bottom edge, said tubular structure defined by a circumferential side wall extending from said top edge to said bottom edge,
said side wall having a lower portion, an intermediate portion, and an upper portion, said lower portion terminating at said bottom edge and said upper portion terminating at said top edge; and
a plurality of symmetrically spaced legs, each leg formed as an outfolding of said side wall, each outfolding beginning at said side wall intermediate portion and extending progressively further outward through said side wall lower portion to said bottom edge,
wherein said side wall further comprises a plurality of symmetrically spaced infoldings, with an infolding between each said outfolding,
with said outfoldings defining external vertices and said infolding defining internal vertices,
and with a plurality of said external vertices of each unit cell nested into internal vertices of adjacent unit cells,
wherein (a) said bottom edges of each said first and second lattice layer are aligned with and connected to one another, (b) said top edges of each said first and second lattice layer are aligned with and connected to one another; (c) said bottom edge of said first lattice layer is aligned with said top edge of said second lattice layer, or (d) a combination thereof.
14. The lattice of claim 1 , wherein said lattice is comprised of metal, polymer, or a composite thereof.
15. The lattice of claim 1 , wherein said lattice is rigid, flexible, or elastic.
16. The lattice of claim 1 , wherein said lattice is produced by a process of additive manufacturing.
17. A cushion, shock absorber, vibration isolater, protective pad or heat exchanger comprising a lattice of claim 1 .
18. A method of making a lattice, or object including a lattice, comprising:
(a) providing a digital model of said lattice or object including a lattice; and then
(b) producing said lattice or object from said digital model by an additive manufacturing process, wherein said lattice comprises:
a plurality of symmetrically oriented repeating unit cells, each of said unit cells comprising a vertically oriented tubular structure having a top edge and bottom edge, said tubular structure defined by a circumferential side wall extending from said top edge to said bottom edge,
said side wall having a lower portion, an intermediate portion, and an upper portion, said lower portion terminating at said bottom edge and said upper portion terminating at said top edge; and
a plurality of symmetrically spaced legs, each leg formed as an outfolding of said side wall, each outfolding beginning at said side wall intermediate portion and extending progressively further outward through said side wall lower portion to said bottom edge,
wherein said side wall further comprises a plurality of symmetrically spaced infoldings, with an infolding between each said outfolding,
with said outfoldings defining external vertices and said infolding defining internal vertices,
and with a plurality of said external vertices of each unit cell nested into internal vertices of adjacent unit cells.
19. The method of claim 18 , wherein said producing step is carried out by selective laser sintering (SLS), fused deposition modeling (FDM), stereolithography (SLA), three-dimensional printing ( 3 DP), or multijet modeling (MJM).