RESEARCH QUESTIONS
  1. How can the components of the piezoelectric harvester structure, energy conditioning circuit, and energy storage system be modified in order to maximize the magnitude of energy stored?
  2. How closely will the theoretical energy harvesting capability of the integrated product compare to the experimentally determined energy harvesting capabilities?
PROJECT

What is Piezoelectricity?

Piezoelectricity, from the Greek ‘piezo-‘ meaning ‘to press’ and ‘electricity’ meaning amber, an ancient source of electric charge, was first discovered by brothers Pierre Curie and Paul-Jacques Curie in 1880. The piezoelectric properties of certain materials immediately became the focus of several studies because they served as a union between the interest in mechanics during the 19th century and the interest in electromagnetics during the 20th century (Ballato, 1994). These properties are most commonly found in crystalline materials, such as quartz, topaz, and sugar cane (Manbachi & Cobbold, 2011). Piezoelectric materials possess the unique ability to produce electrical charge when deformed by mechanical stress, and conversely, when an electrical charge is applied, a deformation occurs at the atomic level, resulting in an alteration of the overall form of the material. The creation of electrical charge from mechanical strain is called the ‘piezoelectric effect’ and the reverse phenomenon is called the ‘inverse piezoelectric effect’ (Manbachi & Cobbold, 2011). These effects are made possible by the electrical dipoles that form in piezoelectric materials when stress creates a distribution of positive and negative charges about the surface. When electric energy is collected from a material with a piezoelectric effect, the energy can be optimized then stored. The stored energy may then be used to power a device. Piezoelectricity has been used in the field of timekeeping, applied to transducers, and utilized in microelectromechanical structures (MEMS) (Ballato, 1994).