A novel approach to optimal design a piezoelectric micro-beam for energy harvesting using Mayfly algorithm

A novel optimization approach employing Mayfly optimization algorithm (MA) to enhance energy harvesting in bilayer piezoelectric microbeams is presented in this paper. Due to the existence of the size-dependent phenomenon, the modified strain gradient effect is applied to establish the size-dependent bilayer piezoelectric microbeam model. Output charge is an important index of energy harvesting in bilayer piezoelectric microbeams. To maximize the output charge, the optimized model of the piezoelectric microbeam is derived, and the ratio of beam length to thickness and piezoelectric thickness to total thickness is used as the design variable for the optimized model. Also, the beam size and deflection limit are used as constraint conditions, and the output charge is used as an objective function. The MA is applied to find the best solution of the objective function that satisfies the constraint conditions. The bilayer piezoelectric microbeam optimal structure that satisfies the constraint condition can be obtained by using the MA. From the results, it can be found that the size effect increases the structural stiffness of the microbeam and reduces the electromechanical coupling response of piezoelectric microbeams. Moreover, the output charge obtained by the optimization structure is much higher than that of the original structure. Compared with the finite element optimal method, the output charge that is obtained by the present method is 4.97% higher than that from the finite element optimal method.