What is the exact amount of power that can derived from a Piezosheet ?

At a frequency mildly below fundamental longitudinal resonance of about 15 KHz after collecting electrical energy stored which is 100% and its height twice per each cycle. Is will also be assumed that PSI-5A (1.5″ x 2.5″ x .0075″) sheet is stretched quasistatically to ±500 microstrains at the frequency mentioned above. Under these circumstances the mechanical energy input in excess would be 100 watts. Efficiency can be added by applying resonant designs.The high stain of 15 KHz excitation cannot be achieved as the mechanical apparatus for making it happen is not available.