Update on Progress.

I haven't posted in a while because iv been extremely busy with university work we have lots of deadlines. and lots of exams to start revising for. 

Since my research i have understood alot more of the technical details of the piezoelectric technology and how this generates electricity. A 3rd year thesis is just not understanding the technical knowledge but proving you are able to become an expert with in depth knowledge of a particular topic or field. To demonstrate that i am able to grasp the engineering principles behind piezoelectric technology i have decided to take a look at the mathematical model of chosen material. The following formula shows the mathematical model needed to obtain the voltage given under a certain pressure. 

Where G31 is the piezoelectric voltage constant and f3 is the resonant frequency constant. To calculate this i first had to calculate my G3 and F3 values which eventually gave me 36.23V and a quiescent current value of 975nA

To prove my mathematical formula was correct i learnt how to use Comsol Multiphysics and proceeded to build a simulation to how the different pressures would effect the output voltage. To do this i had to build all of the properties of my chosen piezoelectric material and then create a mapped mesh, on completion of this i began to apply different pressures and measured the voltage applied. I then programmed Comsoll to preform a preformed a parametric sweep to generate a graph of the of the voltage against pressure as shown below: 

The graph demonstrates a voltage of -33 V being generated with an applied load of 804N this is a negative voltage due to the direction of which the pressure is applied therefore if we were to reverse the direction of pressure the voltage would be positive although this simulation implies a difference of 3.23V from the calculation of section 4. This is due to the material parameter differences and given the correct material programmes these measurements would be more accurate, which demonstrates that the mathematical equations taken from APC Piezoelectric Ceramics publication are of correct form for the PZT Cantilever beam.  The FEA has allows us to critically analyse and demonstrate that our research into Piezoelectric plates used in the direct effect is ‘FACT’ thus allowing us to progress onto developing an energy harvesting circuit to demonstrate the Piezo energy generator.