Overall Thermal Conductivity of Carbon Fiber Polymer Matrix Composites Undergoing Thermal Decomposition

摘要

The objective of this work is micromechanics-based prediction of the effectivelongitudinal and transverse thermal conductivity of carbon fiber reinforced polymer(CFRP) composites at high temperatures, when pyrolytic thermal decomposition ofthe polymer matrix takes place. Microstructure of the composite evolves withtemperature and consists of polymer phase, growing pores, which representpyrolytic gaseous phase, and continuous carbon fibers. Volume fractions ofpolymer and pores at different temperatures are obtained from the Arrhenius-typeequation describing decomposition of the polymer matrix. The char residueproduced during pyrolytic thermal decomposition is not considered in this study.Microstructure generation algorithms are developed to create densely packed,randomly distributed, poly-dispersed, particle filled microstructures consisting ofcircular (representing fibers) and elliptic (representing pores) inclusions. Statisticalanalysis of the generated microstructures is discussed to demonstrate theirsuitability. A two-step numerical homogenization technique is used to compute theeffective directional thermal conductivities of the composite. The computationalresults for the effective transverse and longitudinal thermal conductivities areobtained for the AS4/3501-6 composite in a temperature range up to 700 K.