The effect of interfacial shear strength on damping behavior of carbon nanotube reinforced composites

Abstract

The effect of interfacial shear strength (ISS) on the mechanical and damping properties of carbon nanotube reinforced composites (CNT-RCs) is investigated in the present study using a multiscale simulation. The atomic lattice of CNTs is modeled with the modified molecular structural mechanics (MMSM) approach and reduced to an equivalent beam element (EBE) which is used as the basic building block for the construction of full length CNTs embedded in the polymer. Linear material properties are assigned to the EBEs, while a Maxwell–Wiechert material model is used for modeling the viscoelastic behavior of the polymer. The interfacial load transfer mechanism between the lateral surface of the carbon nanotube and the surrounding matrix is taken into account with a nonlinear bond-slip friction-type model. Finite element models of representative volume elements (RVEs) are constructed comprised of two independent meshes: a structured with solid elements for the matrix and a series of embedded EBEs for the full length CNTs inside the matrix. Straight as well as wavy CNTs are considered. In the case of wavy CNTs, random CNT geometries are generated using the spectral representation method with evolutionary power spectra (EPS) which are derived from processing scanning electron microscope (SEM) images. Stochastic average properties were derived with Monte Carlo simulation. The mechanical and damping properties of the CNT-RCs are assessed on the basis of sensitivity analyses with respect to various weight fractions and interfacial shear strength (ISS) values. Numerical results are presented, showing the significant effect of the ISS as well as the influence of CNT waviness on the damping behavior of CNT-RCs.