Specific features in mechanical behavior of ring-shaped force drives operating in the two-way shape memory effect regime

We have analyzed the possibility of improving deformation–force properties of ring-shaped drives made of titanium nickelide and operating in the regime of two-way shape memory effect (TWSME). For this purpose, thermocycling of an oval sample was used with the transformation of the material from the low-temperature martensite phase to the high-temperature austenite phase in free state and cooling via the temperature interval of the transformation under a load. The possibility of generation of force in ring-shaped structures changing shape during heating as well as during cooling due to the TWSME process is demonstrated. The reported results indicate asymmetry of these properties relative to the direction of temperature variation. It is shown that the cooling rate substantially affects the deformation and force properties of ring-shaped drives.