The Thermal Conductivities of Periodic Fibrous Composites as Defined by a Mathematical Model

Abstract

Abstract:In this paper, a geometric body-centered model to simulate the periodic structure of unidirectional fibrous composites is presented. To this end, three prescribed configurations are introduced to predict in a deterministic manner the arrangement of internal and neighboring fibers inside the matrix. Thus, three different representative volume elements (RVEs) are established. Furthermore, the concept of the interphase has been taken into account, stating that each individual fiber is encircled by a thin layer of variable thermomechanical properties. Next, these three unit cells are transformed in a unified manner to a coaxial multilayer cylinder model. This advanced model includes the influence of fiber contiguity in parallel with the interphase concept on the thermomechanical properties of the overall material. Then, by the use of this model, the authors propose explicit expressions to evaluate the longitudinal and transverse thermal conductivity of this type of composite. The theoretical predictions were compared with experimental results, as well as with theoretical values yielded by some reliable formulae derived from other workers, and a reasonable agreement was found.

Investigations on the effect of hybrid carbon fillers on the thermal conductivity of glass epoxy composites

“…The heat flow across intermittent paths between the conducting filler network is mainly determined by the wt% of the two fillers, their orientation angles, and the interactions between the two fillers and their influences on the adhesion between glass fibers and the epoxy matrix. Based on finite element analysis‐based simulation, [ 34,35 ] it is reported that the random orientation of MWCNT will negatively impact the thermal conductivity, more than that of GNP. Hence, it is critical to fix the wt% of MWCNT and then determine the matching wt% of GNP for optimizing the thermal conductivity.…”