Deployable truss having second order augmentation
A deployable truss is formed from a plurality of column members connected at their ends where at least some of the column members are formed from column assemblies, each including a plurality of strut members that are at least connected to each other at a first and second end of the column assembly. For added rigidity, strut members of a column assembly may be connected to each other between the first and second ends using, for example, a rigidizable resin, a fixed spacer, or a deployable spacer. Connecting strut members between the ends of the column assembly provides mutual bracing to the strut members and decreases the free buckling length of the individual strut members. Spacers are preferably configured to radially space the strut members away from the longitudinal centerline of the column assembly to increase its moment of inertia, and hence its buckling strength.
1. A deployable truss comprising:
a plurality of column members connected at their ends to form a deployable truss that forms a rigid structure in a deployed state and that has a stowage volume less than its deployed volume in a collapsed state, wherein at least one of the plurality of column members comprises a column assembly having at least one tapered end, the column assembly including at least three strut members, each strut member of the column assembly being connected to each other strut member of the column assembly at a first end of the column assembly and at a second end of the column assembly.
2. The deployable truss of claim 1 , wherein the at least three strut members of the column assembly are substantially symmetrically arranged about a longitudinal centerline of the column assembly.
3. The deployable truss of claim 1 , wherein the at least three strut members of the column assembly are further connected to each other at a location between the first and second ends of the column assembly when the deployable truss is in the deployed state.
4. The deployable truss of claim 3 , wherein the at least three strut members of the column assembly are rigidly connected using a rigidizable resin.
5. The deployable truss of claim 4 , wherein the rigidizable resin comprises a thermoplastic resin.
6. The deployable truss of claim 4 , wherein the rigidizable resin comprises a UV curable resin.
7. The deployable truss of claim 3 , wherein the at least three strut members of the column assembly exhibit a substantially helical twist about a longitudinal centerline of the column assembly.
8. The deployable truss of claim 1 , wherein the column assembly further comprises a spacer connecting the at least three strut members of the column assembly at a location between the first end and the second end of the column assembly.
9. The deployable truss of claim 8 , wherein the spacer connects the at least three strut members of the column assembly near a midpoint between the first and second ends of the column assembly.
10. The deployable truss of claim 8 , wherein the spacer is collapsible to a stowed configuration when the deployable truss is in the collapsed state and expandable to a deployed configuration that radially spaces the at least three strut members of the column assembly away from a longitudinal centerline of the column assembly when the deployable truss is in the deployed state.
11. The deployable truss of claim 8 , wherein the spacer comprises a rigid spacer that radially spaces the at least three strut members of the column assembly away from a longitudinal centerline of the column assembly a fixed distance in both the deployed and collapsed states.
12. The deployable truss of claim 11 , wherein the spacer is substantially V-shaped.
13. The deployable truss of claim 8 , wherein the at least three strut members of the column assembly taper toward a longitudinal centerline of the column assembly at the first end and the second end of the column assembly when the deployable truss is in the deployed state.
14. The deployable truss of claim 1 , wherein each column assembly further comprises a plurality of spacers connecting the at least three strut members of the column assembly, each of the plurality of spacers connecting the at least three strut members of the column assembly at a different location between the first end and the second end of the column assembly.
15. The deployable truss of claim 14 , wherein each spacer is collapsible to a stowed configuration when the deployable truss is in the collapsed state and expandable to a deployed configuration that radially spaces the at least three strut members of the column assembly away from a longitudinal centerline of the column assembly when the deployable truss is in the deployed state.
16. The deployable truss of claim 14 , wherein each spacer comprises a rigid spacer that radially spaces the at least three strut members of the column assembly away from a longitudinal centerline of the column assembly a fixed distance in both the deployed and collapsed states.
17. The deployable truss of claim 16 , wherein each spacer is substantially V-shaped.
18. The deployable truss of claim 17 , wherein the spacer of each column assembly is arranged to permit nesting with the spacer of another column assembly when the deployable truss is in the collapsed state.
19. The deployable truss of claim 14 , wherein the at least three strut members of the column assembly taper toward a centerline of the column assembly at each of the first end and the second end of the column assembly when the deployable truss is in its deployed state.
20. The deployable truss of claim 1 , wherein at least one of the at least three strut members comprises a tube.
21. The deployable truss of claim 1 , wherein at least one of the at least three strut members comprises a rod.
22. The deployable truss of claim 1 , wherein each of the at least three strut members is formed from a continuous fiber reinforced composite material.
23. The deployable truss of claim 22 , wherein the continuous fiber reinforced composite material comprises glass fibers.
24. The deployable truss of claim 22 , wherein the continuous fiber reinforced composite material comprises graphite fibers.
25. The deployable truss of claim 1 , wherein each end of the column assembly is tapered.
26. A deployable truss comprising:
a plurality of column members connected at their ends to form a deployable truss that forms a rigid structure in a deployed state and that has a stowage volume less than its deployed volume in a collapsed state, wherein at least some of the plurality of column members comprise column assemblies including a plurality of strut members, each strut member of an associated column assembly being connected to each other strut member of the associated column assembly at a first end of the column assembly and at a second end of the column assembly, wherein strut members of a column assembly are further connected to each other at a location between the first and second ends of the column assembly when the deployable truss is in the deployed state, and wherein at least some of the strut members of the plurality of strut members of the column assembly exhibit a substantially helical twist about a longitudinal centerline of the column assembly.