Thermal conductivity of a thermosetting advanced composite during its cure

Abstract

The thermal conductivity of a thermosetting advanced composite material during its cure was experimentally investigated and compared to analytical models. The thermal conductivity of graphite/epoxy was experimentally measured using a guarded hot plate apparatus. The through-thickness transverse thermal conductivity of composite laminates was measured at various resin degrees of cure and fiber volume fractions while using various ply lay-up angles. The in-plane thermal conductivity was measured using unidirectional laminates, as well as laminates with various ply lay-up angles. Techniques for manufacturing composite laminates with these various properties, as well as the guarded hot plate apparatus necessary for accurate measurements, are described. Finally, various analytical models were researched, and those that compare most favorably with the experimental data are presented. NomenclatureH c = thermal contact conductance of the experiment, W/m 2°C H r = resin heat of reaction for AS4/3501-6, J/g K = thermal conductivity, W/m°C L = laminate dimension in the x direction, m N = number of plies in a laminate p = function of the fiber volume fraction, Eq. (6) Q = total heat flux, W q = heat flux/area, W/m 2 q = resin energy generation rate per unit volume, W/m 3 q ln = heat flux/area applied by the guarded hot plate, W/m 2 T = temperature, °C t = laminate dimension in the z direction, m V = volume fraction of a constituent material W = laminate dimension in the y direction, m *, v, z = laminate coordinates defined in Fig. 1 a = resin degree of cure, scale of 0-1.0 y = function of material conductivities, Eq. (11) 8 = resin rectangle side parallel to measured K, fjun e = resin rectangle side J_ to measured K, /mi 0 = direction of ply alignment, Fig. 1, deg v' = function of material conductivities, Eq. (5) p = density, g/m 3 Subscripts act s= actual material property c = experimental setup contact region property comp = composite property

Stochastic Multi-Objective Optimisation of Composites Manufacturing Process

“…The thermal conductivity of the anisotropic composite material in the longitudinal direction is computed using an appropriate geometry-based model [13] and can be expressed as follows:…”

Inverse heat transfer for optimization and on-line thermal properties estimation in composites curing

“…The thermal conductivity of the anisotropic composite material is computed using an appropriate geometry-based model [12] that combines values for the resin and the carbon fiber. The values for the resin were obtained experimentally using a technique that measures the thermal conductivity of the thermoset while it cures.…”

Role of in-plane stacking sequence on transverse effective thermal conductivity of unidirectional composite laminates

“…This paper will explore laminated heterogeneous systems and study the dependence of the in-plane fiber volume fraction and fiber tow angle-ply sequence on the through-thickness thermal conductivity. Previous studies [6][7][8] did not explore in detail the effect of in-plane fiber tow orientation on transverse thermal properties. In this numerical study, the role of various microstructural arrangements and fiber tow contact points that influence the transverse thermal conductivity are characterized and their influence on effective transverse thermal conductivity of laminated composites is quantified.…”