Reconfigurable shape memory polymer tooling supports
View Patent ↗A method and support apparatus for providing structural support to a mold or mandrel, such as a shape memory polymer (SMP) apparatus configured for shaping a composite part. The support apparatus may comprise a rigid structural member and a plurality of SMP cells attached thereto and configured to inflate or deploy in a malleable state toward and against a surface of the SMP apparatus, mold, or mandrel. Then the SMP cells may be returned to a rigid state while still pressed against this surface, thereby providing structural support when composite material is applied to an opposite surface of the SMP apparatus, mold, or mandrel. After the composite material is cured into the finished composite part, the SMP cells may be deflated or otherwise collapse toward the structural member to provide enough clearance to be removed from the cured composite part.
1. A method of forming a composite part on an SMP apparatus composed of shape memory polymer (SMP), the method comprising:
placing a support apparatus proximate to at least one surface of the SMP apparatus, wherein the support apparatus comprises:
a rigid structural member that remains rigid when heated to a temperature sufficient for curing a composite part,
a plurality of inflatable SMP cells made of shape memory polymer (SMP) configured to be actuated to transition between a rigid state and a malleable state, and
a pressurization system configured to inflate the SMP cells away from the rigid structural member when the SMP cells are in the malleable state;
actuating the SMP cells to the malleable state;
inflating the SMP cells with the pressurization system such that the SMP cells press against the at least one surface of the SMP apparatus while in the malleable state;
actuating the SMP cells to the rigid state while the SMP cells are pressed against the at least one surface of the SMP apparatus, thus providing a rigid load path between the SMP apparatus and the rigid structural member; and
applying uncured composite material to a surface of the SMP apparatus opposite of the at least one surface of the SMP apparatus in contact with the SMP cells.
2. The method of claim 1 , wherein the SMP cells are in the rigid state at temperatures below T g and are actuated into the malleable state when heated above T g .
3. The method of claim 1 , further comprising placing the SMP apparatus against at least one mold surface before the step of inflating the SMP cells, such that inflating the SMP cells sandwiches the SMP apparatus between the SMP cells and the at least one mold surface.
4. The method of claim 1 , further comprising extending or retracting rods of the rigid structural member to place the SMP cells a desired distance away from the SMP apparatus.
5. The method of claim 1 , further comprising:
curing the composite material to form the composite part;
actuating the SMP cells to the malleable state then deflating the SMP cells; and
removing the support apparatus and SMP apparatus from the composite part.
6. The method of claim 1 , wherein the rigid structural member comprises a center support structure and extension support members attached to the center support structure in a spoke-like configuration, wherein the SMP cells are attached to the extension support members at or proximate to ends thereof.
7. The method of claim 6 , wherein the steps of actuating the SMP cells to a malleable state and inflating the SMP cells is performed by at least one of a pressurization system, an oven, an autoclave, and a heat exchanger.
8. The method of claim 5 , wherein a pressurization system applies vacuum to the SMP cells to deflate the SMP cells.