Actuator and tubular actuator

1. An actuator, comprising a tubular configured to longitudinally expand in response to radial expansion of at least a portion of the tubular a wall of the tubular having at least one sinuous member having longitudinal amplitude and a plurality of bars being in operational communication with the at least one sinuous member and alternately directed ends of two of the plurality of bars are connected to one of the at least one sinuous member such that the alternately directed ends overlap longitudinally.

2. The actuator of claim 1 , wherein a wall of the tubular is discontinuous.

3. The actuator of claim 1 , wherein the two of the plurality of bars are perimetrically adjacent.

4. The actuator of claim 1 , wherein an amount of the overlap decreases in response to a decrease in amplitude of the at least one sinuous member.

5. The actuator of claim 1 , wherein the plurality of bars are configured to transmit compressive loads.

6. The actuator of claim 5 , wherein the compressive loads are directed substantially longitudinally.

7. The actuator of claim 1 , wherein the at least one sinuous member includes a plurality of substantially straight portions.

8. The actuator of claim 7 , wherein angles between the plurality of substantially straight portions and the plurality of bars increase in response to the radial expansion of the actuator.

9. The actuator of claim 1 , wherein the actuator is configured so that the longitudinal amplitude of the at least one sinuous member decreases in response to radial expansion thereof.

10. The actuator of claim 1 , wherein the tubular is metal.

11. The actuator of claim 1 , wherein a wall of the tubular is continuous.

12. The actuator of claim 1 , wherein the tubular fluidically seals an inside from an outside thereof.

13. The actuator of claim 1 , wherein a wall of the tubular has a longitudinally oriented serpentine shape.

14. The actuator of claim 13 , wherein the longitudinally oriented serpentine shape has a radially defined amplitude.

15. An actuator, comprising a tubular configured to longitudinally expand in response to radial expansion of at least a portion of the tubular, having a sleeve in operable communication with the actuator such that a first end of the actuator is fixed to a first portion of the sleeve and a second end of the actuator moves longitudinally in relation to a second portion of the sleeve in response to radial expansion of the actuator.

16. A tubular actuator, comprising:

a sleeve; and

a tubular in operable communication with the sleeve configured to longitudinally expand in response to radial expansion thereof, a first portion of the tubular being longitudinally fixed to the sleeve so that a second portion of the tubular moves in relation to the sleeve in response to the longitudinal expansion of the tubular.

17. The tubular actuator of claim 16 , wherein the sleeve has a nonnegative Poisson's ratio.

18. The tubular actuator of claim 16 , wherein tubular and the sleeve are nested together.