Stress waves in a lightweight substrate plate actuated with piezoelectric layers under sinusoidal time-dependent pressures

Abstract

The dynamic behavior of cantilever lightweight substrate plates actuated by surface layers of piezoceramic with a potential application as an energy harvester is presented in this paper. The utilized passive substrate is made of nanocomposite plates with embedded pores where both nanofillers and pores are functionally graded (FG) distributed. Carbon nanotubes (CNTs) are employed as the enhancement part of the substrate whereas their major distribution drawback which is CNT accumulating in some clusters has been taken into account by employing a modified Eshelby's approach for the calculation of nanocomposite's material properties. The proposed structure is assumed under a half wave of sinusoidal time-dependent pressure to model an impact load and by providing a meshless solution, its dynamic behavior in a framework of stress wave propagation analysis has been conducted. By exploring porosity and CNT effects, the achieved results revealed that there is an optimum value for porosity volume fraction which offers the highest wave frequency. Moreover, it was observed that although there is a great difference between stress waves in structures with pure polymeric and nanocomposite substrates, involving higher CNT amounts without a perfect distribution would considerably reduce the enhancement efficiency of CNTs due to accumulating CNTs in some clusters.