Surface stress effect on nonlinear dynamical performance of nanobeam-type piezoelectric energy harvesters via meshless collocation technique

The chief point of the present study is to analyze numerically the surface stress effects on the nonlinear dynamic performance of nanosized lightweight piezoelectric bridge-type energy harvesters having agglomerated nano -composite passive bulk. In this regard, the Gurtin-Murdoch continuum elasticity is formulated based upon the quasi-3D beam theory incorporating the relevant surface elastic constants as well as the surface residual stress. Afterwards, an effective numerical solving procedure employing the meshless collocation technique is developed to discretize the nonlinear governing equations via a combination of the polynomial as well as multiquadric basis functions to avoid any possible singularity. It is indicated that the surface stress effects result in to decrease the peaks of achieved voltage from the nonlinear dynamical response of nanobeam-type energy harvesters, but the associated frequency increases. Accordingly, for simply supported nanosized energy harvesters having the thickness of 50nm, 20nm, and 10nm, the reductions in the average achieved voltage in order are about 7.79%, 25.57%, and 37.98%, but the required time decreases from 40.41 mu s to 39.78 mu s, from 35.17 mu s to 33.57 mu s, and from 28.37 mu s to 26.46 mu s, respectively. On the other hand, for clamped nanosized energy harvesters having the thickness of 50nm, 20nm, and 10nm, the reductions in the average achieved voltage due to the surface stress effects are, respectively, about 8.33%, 27.35%, and 48.85%, but the required time decreases from 38.92 mu s to 38.43 mu s, from 33.42 mu s to 32.04 mu s, and from 26.58 mu s to 24.62 mu s, respectively.