Multiscale Mass-Spring Models of Carbon Nanotube Foams

摘要

This article is concerned with the mechanical properties of dense, vertically aligned carbon nanotube foams subject to one-dimensional compressive loading. We develop a discrete model directly inspired by the micromechanical response reported experimentally for CNT foams, where in nitesimal portions of the tubes are represented by collections of uniform bi-stable springs. Under cyclic loading, the given model predicts an initial elastic deformation a non- homogeneous buckling regime, and a densi cation response, accompanied by a hysteretic unloading path. We compute the dynamic dissipation of such a model through an analytic approach. The continuum limit of the microscopic spring chain de nes a mesoscopic dissipative element (micro-meso transition), which represents a nite portion of the foam thickness. An upper scale model formed by a chain of nonuniform mesoscopic springs is employed to describe the entire CNT foam. A numerical approximation illustrates the main features of the proposed multiscale approach. Available experimental results on the compressive response of CNT foams are tted with excellent agreement.