Simplified Rule-of-Mixture Model to Predict the Elastic Modulus of Brake Linings with High Viscoelastic Content

This work presents the modeling and investigation of the mechanical behavior of brake pad materials with high viscoelastic content, reinforced with particles and fibers. A simplified model is presented, with the purpose of prediction of the elastic modulus of this class of material. The model consists in the modification of the Rule of Mixtures, with the introduction of a term referring to the particle phase present in the composite material. It is introduced an alignment factor, in order to adjust the magnitude of orientation of the fibers in the stage of material compaction process. Also, the influence of the viscoelastic phase is modeled according to the percolation theory. Three standard brake pad materials with different viscoelastic contents were produced and tested. The composite materials produced were tested by three-point bending, in order to determine their mechanical properties. The comparison between mechanical properties obtained experimentally and the theoretical results demonstrate good agreement with the real behavior of the composite material.