Numerical study on rheological properties of epoxy/SiO2 ternary packing composites

Polymer matrix composites with shear thinning properties have a wide range of applications in the field of electronic packaging. The rheological properties of composite materials are critical to realization of specific functions. The optimization of filler gradation scheme is an effective method to improve fluidity of composites under high filling content. Nevertheless, the effect of filler gradation on the flow properties of composites with multiple filler sizes is not yet fully understood.In this paper, we investigated the shear thinning flow behaviors of epoxy/SiO
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ternary packing composites by semi-resolved CFD-DEM coupling method. Through the dynamic analysis of the shear stress distribution, velocity distribution and particle contact force networks of the composite system, it was found that the friction between the fillers of the composites with the optimal gradation is significantly reduced. Although the friction effect between particle is enhanced at high shear rate, the epoxy/SiO
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composites shows shear thinning characteristics. Our work will help to improve the understanding of the mechanisms of shear thinning.