Agglomeration effects of CNTs on the energy harvesting performance of multifield interactive magneto-electro-elastic/nanocomposite unimorph smart beam

In this article, the effect of agglomeration of carbon nanotubes (CNTs) on the energy harvesting behavior of a unimorph multifunctional cantilever beam (UMCB) subjected to transverse and rotational vibrations is investigated analytically using a distributed parameter model. The top layer of the UMCB consists of the magneto-electro-elastic (MEE) material, formed by reinforcing a piezoelectric matrix with CNTs, acting as a piezomagnetic phase. The substructure of the UMCB is composed of a nanocomposite CNTs material. To address the issue of dispersion of the material, agglomeration or cluster formation of the CNTs in the substrate layer is considered. The agglomeration is modeled using the modified Eshelby-Mori-Tanaka (EMT) method. The ideal case of no agglomeration, partial and complete agglomeration, is considered for evaluation. The various distributions of the CNTs in the substrate and its volume fractions are also considered in the analysis. The coupled governing equations of motion and the subsequent frequency-response functions (FRFs) for the output parameters are derived based on the distributed parameter approach, in conjunction with the Euler-Bernoulli beam theory, Gauss and Faraday's laws. Various material and geometrical parametric studies are discussed in detail to understand the output response of the UMCB. Special focus is placed on the effect of the agglomerated CNTs substrate and the influence of various agglomeration parameters on the overall output response. The article is a stepping stone to developing and utilizing advanced composite structure-based energy harvesting devices and paves the way for further research into utilizing CNTs-based composite structures for various engineering applications.