High displacement non-linear asymmetrically designed piezoelectric actuators

Non-linear smart actuators have attracted lately the interest of many researchers. It is well known that linear smart actuators have been used in a vast number of applications in different disciplines. However, most of the times a trade off between displacement and force must take place in order to increase their operational envelope. Taking into account this, it is not strange that research is headed towards non-linear mechanics in order to increase displacement, as well as force actuation in smart actuators. In the present work, issues related with the non-linear response of smart beams as well as snap-through performance are investigated. Beams with aluminum cores are equipped with continuous piezoelectric layers that cover only a certain part of the structure. A number of symmetrical and asymmetrical actuators have been realized with different core lengths and thus the amount of active material over the whole length of the actuator varies. These actuators were tested in order to evaluate their critical buckling load as well as their snap-through performance. The snap-through displacement was examined with respect to the post-buckling compression of the actuators for all the configurations and the difference between symmetrical and asymmetrical actuators raises a number of issues concerning the design of such actuators.