Thermal analysis of filler reinforced polymeric composites
Abstract
Improving heat dissipating property of composite materials is becoming increasinglyimportant in domains ranging from the automotive industry, electronic devices toaeronautical industry. Effective heat dissipation is required especially in aircraft andracing tires to guarantee high performance and good service life [1]. The presentstudy is focused on improving the thermal conductivity of Emulsion-styrene butadienerubber (ESBR) which is a cheap alternative to other rubber composites. Thedisadvantages of ESBR are low thermal conductivity and high heat generation.Adding fillers with high thermal conductivity to ESBR is proposed as a techniquefor improving the thermal conductivity of ESBR. The purpose of the research is to predictthe thermal conductivity of ESBR when filled with fillers of much higher thermalconductivity and also to find out to what extent the filler properties affect the heattransfer capabilities of the composite matrix. The influence of different filler shapesi.e. spherical, cylindrical and platelets on the overall thermal capability of compositematrix is studied, the finite element modelings are conducted using Abaqus. Three-dimensionaland two-dimensional models are created in Abaqus to simulate the microstructure of the composite matrix filled with fillers.Results indicate that the overall thermal conductivity increases with increasingfiller loading i.e. for a filler volume fraction of 0.27, the conductivity increased byaround 50%. Filler shapes, orientation angle, and aspect ratio of the fillers significantlyinfluences the thermal conductivity. Conductivity increases with increasing aspectratio (length/diameter) of the cylindrical fillers since longer conductive chains areable to form at the same volume percentage as compared to spherical fillers. Thecomposite matrix reaches maximum thermal conductivity when the cylindrical fillersare oriented in the direction of heat flow.The heat conductivity predicted by FEM for ESBR is compared with that predictedby mean field theories. At low volume fractions the FEM and mean field theoryresults are matching. However, at high volume fractions, the results obtained by thetwo methods are not in agreement. This is due to the fact that mean field theorydo not consider the particle interactions happening at higher volume fractions.The present analysis can be used to tailor the thermal properties of ESBR forrequired thermal conductivity for a wide range of applications such as racing tires,electronic gadgets or aeronautical components. In addition, the proposed FEM modelscan be used to design and optimize the properties of new composite materialsproviding more insight into the thermal conductivity of composite polymers and aidin understanding heat transfer mechanism of reinforced polymers.