The coupling between strain gradients and polarization is called Flexoelectricity. This phenomenon exists in all dielectrics with any symmetry that its discovery dates back several decades ago. Nevertheless, there are afew researches on flexoelectricity in solids due to small value of this phenomenon in bulk samples. However, the favour of flexoelectricity has renewed with progress of nanoscale technologies. In this research, the basis of the flexoelectricity and the potential applications of this electromechanical effect is introduced. In particular, energy harvesting (here the converting ambient mechanical vibrations to electrical energy) can be one of the attractive applications of this effect. Then, to more precise study of effect and effective parameters in energy harvesting, Timoshenko beam model is developed with flexoelectric and straing gradient effects.General govering equations and related boundry conditions are derived using variational and Hamilton principel for flexoelectricity with considering of normal and shear strains. The flexoelectric effect induced by gradients of these strains lead to more general model. Deformations and performance curves of the system include deflection, rotation, voltage, power density and etc are ploted. The variations of flexoelectric coefficients, strain gradient constants, base acceleration and attaching tip mass is discussed too. Results show that flexoelectricity has great effect on energy harvester performance and significantly increased from micro to submicron and nano scales. In addition, the flexoelectricity has considerable impact on beam deformations and make the beam behavior become softer. Thus, both the rotation and deflection obtained by this new model is larger than predicted value by left; LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt; unicode-bidi: embed; DIRECTION: ltr" Keywords: Energy harvesting, Flexoelectricity, electromechanical coupling, strain gradient, Timoshenko beam theory, hort circuit natural frequency, open circuit natural frequency
