Thermal conductivity of multiphase particulate composite materials

Hollow particle filled composites, called syntactic foams, are used in weight sensitive structural applications in this paper. In this paper, homogenization techniques are used to derive estimates for thermal conductivity of hollow particle filled composites. The microstructure is modeled as a three-phase system consisting of an air void, a shell surrounding the air void, and a matrix material. The model is applicable to composites containing coated solid particles in a matrix material and can be further expanded to include additional coating layers. The model is successful in predicting thermal conductivity of composites containing up to 52% particles by volume. Theoretical results for thermal conductivity are validated with the results obtained from finite element analysis and are found to be in close agreement with them. A simplified approximation of the theoretical model applicable to thin shells is also validated and found to be in good agreement with the corresponding finite element results. The model is applicable to a wide variety of particulate composite materials and will help in tailoring the properties of particulate composites as per the requirements of the application.