I don't get it, what makes this mech-fish swim exactly?

‘Thubber’ – Stretchable, thermally conductive rubber for heated garments and robot muscles | Braceworks Custom Orthotics https://braceworks.ca/2017/02/13/health-tech/thubber-stretchable-thermally-conductive-rubber-for-heated-garments-and-robot-muscles/

And what is the big deal about this Thubber material? Seems like its just a bunch of metal embedded in the rubber to help in conduct heat.
Stuff seems expensive.Gallium Indium Tin eutectic, 99.99% (metals basis), Thermo Scientific Chemicals https://www.thermofisher.com/order/catalog/product/014634.18

 

I can't access the link, but I found this about liquid metals.


-Will

 

There is also memory metals, which can resume there shape, without liquefying. I believe some nitinol wire has been used to produce demonstration motors.

Nitinol Wire: Properties, Applications & Processing https://www.laserwiresolutions.com/nitinol-wire-properties-applications-and-processing-solutions/

 

Read this.
https://www.webpages.uidaho.edu/fish511/Readings/Readings 2010/Liao_2007_Phil.Trans._B.pdf

 

Probably heat source pulse inside the fish body make LMEE actuator move .
Researchers engineer "thubber," a stretchable rubber that packs a thermal conductive punch, for heated garments and robot muscles https://www.prnewswire.com/news-releases/researchers-engineer-thubber-a-stretchable-rubber-that-packs-a-thermal-conductive-punch-for-heated-garments-and-robot-muscles-300406239.html

 

The fish actuator is an SMA - Shape Memory Actuator. The power source is external. The SMA is selectively heated by pulses (This one works a bit like a bimetalic strip, but uses solid-phase phase transitions - something like hot bend left, cool bend right.) The rate at which the actuator can function is determined by the the rate of heat dissipation. Thubber lets the actuator run at twice the frequency of regular elastomer sealants (10 Hz vs 5 Hz according to the article).

 

thx, Phil, figured it was something like that