Computational Micromechanics Investigation of Percolation and Effective Electro-Mechanical Properties of Carbon Nanotube/Polymer Nanocomposites using Stochastically Generated Realizations: Effects of Orientation and Waviness

Abstract

The electrical and mechanical properties of carbon nanotube/polymer nanocomposites depend strongly upon several factors such as CNT volume fraction, CNT alignment, CNT dispersion and CNT waviness among others. This work focuses on obtaining estimates and distribution for the effective electrical conductivity, elastic constants and piezoresistive properties as a function of these factors using a stochastic approach with numerous CNT/polymer realizations coupled with parallel computation. Additionally, electrical percolation volume fraction and percolation transitional behavior is also studied. The effective estimates and percolation values were found to be in good agreement with experimental works in the literature. It was found that with increasing CNT volume fraction, the mechanical properties improved. However, due to the interaction of CNTs with one another through electrical tunneling, the conductivity and piezoresistivity properties evolved in a more complex manner. While the degree of alignment played a strong role in the effective properties making them anisotropic, the effect of waviness was found to be insubstantial.

Computer Simulation of Composite Materials Behavior under Pressing

“…The first step is to determine the effect of heat treatment, which is preceded by mechanical treatment, based on the basic principles of building three-dimensional structural models of composites based on statistical data on the mechanical properties (elastic, plastic, and strength) of inclusions and matrix, finite element models of composites are built in the ANSYS Workbench program. A stress–strain diagram is obtained by simulating the stretching process of a sufficiently small element of a cubic-shaped composite [ 43 , 44 , 45 ]. The material’s strength and bearing capacity are considered with an analysis of the accumulation of damage in the model [ 46 , 47 ].…”

Cation Bimetallic MOF Anchored Carbon Fiber for Highly Efficient Microwave Absorption

“…[32][33][34][35] Recently, in view of the relatively low percolation threshold value of 1D fillers, [36,37] a novel microwave absorber of CNTs-anchored MOF derivatives was constructed, which presented a wide effective absorption band (EAB) of 6.7 GHz and minimum reflection loss (RL min ) of −59.8 dB with a mass percent of only 9 wt.%. Although the impedance matching problem has been solved and desirable MA performance was achieved, it can be noted that the mass percent of absorbers is still high compared with that of many carbon fillers used as reinforcing filler (eg, CNTs (0.1-6 wt.%), [38][39][40][41][42] graphene (0.5-5 wt.%), [43][44][45][46][47] carbon black (1-5.5 wt.%), [48,49] CF (0.5-5.5wt.%), etc. [50][51][52] ), which will inevitably lead to the deterioration of the mechanical properties of the final composite.…”