Work-per-volume

The very high work-per-volume ratio of approx. 4 J/cm is highly valued if space is limited. SM actuators offer high forces and strokes. For example, a piezoelectric actuator with the same force and stroke would have to use up to ten times the space necessary for a SM actuator. 

The advantages offered by shape memory actuators become most obvious where small-sized devices are concerned. Due to the very high work-per-volume ratio, SM actuators of millimeter or micrometer dimensions have large actuator strokes and forces. The response time strongly decreases with shrinking actuator size. 

Actually this is work per volume, cf. (1.4). However, if we do the same calculation just for the first quarter cycle (form zero to maximum shear strain) the result is... 

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