This paper proposes a novel curved shape piezoelectric unimorph called PUMPS (piezoelectric
unimorph with mechanically pre-stressed substrate) that uses a new and simple fabrication
method. Generally, conventional pre-stressed curved shape unimorphs are made by using
high-temperature adhesion processes and the thermal expansion coefficient mismatch of their
constituent layers. In the conventional methods, therefore, it is necessary to use materials with
different thermal expansion coefficients, high-temperature ovens or autoclaves, and special
adhesives. In addition, the conventional methods generally require the re-poling of the
piezoceramic actuator layer due to high-temperature adhesion near or above the Curie
temperature of the piezoceramic. The present fabrication method uses mechanically
pre-stressed substrates and a room temperature adhesion process instead of relying on a thermal
coefficient mismatch. First, a substrate material is strained in the longitudinal direction and then
a piezoelectric material is attached to the substrate. A difference of mechanical strains between
the substrate and the piezoelectric layer causes the final manufactured actuator to curve. In this
way, a new type of curved shape pre-stressed piezoelectric unimorph, PUMPS, can be easily
fabricated at room temperature and can be used as a sensor, an actuator and an
energy-harvesting element without the necessity of a re-poling process. A series of performance
tests on the proposed PUMPS actuators was accomplished and the test results show that the
actuation capability of PUMPS is comparable to that of conventional curved shape actuators,
in spite of the much simpler manufacturing process.