Modified strain gradient plate model for nonlinear dynamics of sinusoidal impulsive actuated porous/piezoelectric laminated microharvesters

Abstract

Size dependency plays an important role in mechanical responses of structures at microscale. In this regard, within the framework of the modified strain gradient theory (SGT), the nonlinear dynamic characteristics of porous/piezoelectric laminated energy microharvesters under sinusoidal impulsive mechanical actuation are explored. The through-thickness porosity dispersion pattern relevant to the passive core of the considered laminated microharvesters is assumed based upon three different functions including a uniform and two graded ones satisfying the necessary requirements associated with the rule of Gaussian random field. In order to derive numerically the solution of the constructed microscale-dependent energy harvester model, the meshless collocation approach as an efficient subset of the meshfree technique is utilized possessing multiquadric radial basis function. It is indicated that by considering a higher value for the microstructural gradient parameters utilized in the SGT-based microharvester model leads to a more prominent effect of the strain gradient tensors which makes more decrement in the value of attained voltage. In this regard, for the laminated energy microharvester under simply edge condition, the value of attained voltage reduces from 232.9795mv in the conventional case to the SGT-based value of 224.1054μv (3.81% decrement) associated with the microstructural gradient parameters equal to 15μm, to the SGT-based value of 208.8456mv (10.36% decrement) associated with the microstructural gradient parameters equal to 30μm, and to the SGT-based value of 175.1994mv (24.80% decrement) associated with the microstructural gradient parameters equal to 45μm. On the other hand, for the laminated energy microharvester under clamped edge condition, the value of attained voltage reduces from 119.3314mv in the conventional case to the SGT-based value of 114.6559mv (3.92% decrement) associated with the microstructural gradient parameters equal to 15μm, to the SGT-based value of 104.2985mv (12.60% decrement) associated with the microstructural gradient parameters equal to 30μm, and to the SGT-based value of 81.6482mv (31.58% decrement) associated with the microstructural gradient parameters equal to 45μm.