Design and performance of variable-shaped piezoelectric energy harvesters

• Published in: Journal of intelligent material systems and structures Vol. 25; no. 2; pp. 174 - 186
• Main Authors: Ben Ayed, Samah, Abdelkefi, Abdessattar, Najar, Fehmi, Hajj, Muhammad R
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-01-2014; Sage Publications
• Subjects: Cantilever beams; Design engineering; Energy harvesting; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Galerkin methods; General equipment and techniques; Harvesters; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mathematical models; Measurement and testing methods; Physics; Piezoelectricity; Resistivity; Servo and control equipment; robots; Solid mechanics; Structural and continuum mechanics; Transducers; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Voltage; differential quadrature method; distributed model; Energy harvesting; variable-shaped beams; piezoelectric material; Resistors; Modal analysis; Form defect; Eigenfrequency; Low frequency; Cantilever beam; Vibrations; Piezoelectric transducers; Voltage; Piezoelectricity; Modelling; Reduced order systems; Quadratures; Unimorph transducer; Energy recovery; Rectangular shape; Low energy; Galerkin-Petrov method; Added mass; Piezoelectric materials; Vibrational modes; Electric resistivity; Resonance; Differential method; Electromechanical properties
• ISSN: 1045-389X; 1530-8138
• DOI: 10.1177/1045389X13489365

We investigate the effects of shape variations of a cantilever beam on its performance as an energy harvester. The beam is composed of piezoelectric and metallic layers (unimorph design) with a rigid mass attached to its free end. A reduced-order model based on a one-mode Galerkin approach is derived. Solutions for the tip displacement, generated voltage, and harvested power are then obtained. Linear and quadratic shape variations are considered in order to design piezoelectric energy harvesters that can generate energy at low frequencies and maximize the harvested energy. The results show that the fundamental natural frequency and mode shape are strongly affected when the shape of the beam is varied. The influence of the electrical load resistance and the shape parameters at resonance on the system’s performance is discussed. It is determined that for specific resistance values, the quadratic shape can yield up to two times the energy harvested by a rectangular shape.