Comment on 'modeling and analysis of a bimorph piezoelectric cantilever beam for voltage generation'

In a recent paper, Ajitsaria et al (2007 Smart Mater. Struct. 16 447-54) presented a mathematical formulation for the modeling and analysis of a bimorph piezoelectric cantilever beam for voltage generation. Their motivation was the recent increasing trend in using the piezoelectric effect to harvest electrical energy from ambient vibrations. This comment addresses the modeling errors and numerous undefined and missing terms in the mentioned work.