Four Shape Memory Alloy pipe couplings concepts with "weld like" leak performance.
Four SMA coupling concepts
After extensive testing of different Shape Memory Alloy grades (here some insights for one material), non-linear Finite Element Modelling and subsequent detailed design activity, four pipe coupling concepts have been obtained, with a leak performance as perfect as welds, without the drawbacks of large keep-out zones for orbital welding head, X-Ray inspection, operator qualification or need for cryogenics (storage, installation).
Typical applications of these pipe joints can be propulsion systems of satellites (liquid or electric), GHe circuit of pneumatically actuated rocket engine valves, hydraulic circuit of Thrust Vector Control actuators or any other similar space or non-space application, in particular bi-metal joints or connections between pipes of different diameters.
Next step: endurance testing of most suitable concept in even more representative environment.
Samples after testing
Typical supply conditions (non-cryogenic version)
- Install the (blue) joint locator in such a way that the pipe joint appears in the center of the hole.
- Install the (red) Coupling installation locator in such a way that it touches the (blue) joint locator.
- Remove the (blue) joint locator.
- Install the (yellow) coupling in such a way that it touches the (red) coupling installation locator.
- Heat-up the coupling to trigger temperature.
- The coupling shrinks.
- Remove the (red) locator.
- DONE! No X-ray needed.