Abstract
SMA springs (coil springs of shape memory alloy) show some characteristics including material nonlinearity, temperature dependency, and hysteresis different from those of usual metal springs: so that SMA springs can not be designed by using the traditional design formula as it is.
This paper studies dynamic properties of SMA springs on the basis of the governing equation of usual springs and introduces a design formula of SMA springs by taking account of twisting test results of element wires and loading test results of SMA springs. The design system of SMA springs based on the computer-aided data base has been developed; so that can now calculate characteristics by loading in acting state of springs and hysteresis which are difficult to be shown by making drawings.
