Fluid Transport Phenomena During the Engagement of Fiber-Reinforced Polymeric Friction Materials

Two important phenomena which govern the performance of wet friction composite materials operating in transmission oils have been examined. Both the elastic deformation behavior, and the liquid permeability of fiber reinforced polymeric wet friction composite materials are important input parameters to any accurate oil flow model which predicts the interface temperature of wet friction clutch facing polymeric materials. Liquid permeability, pore size, and pore size distribution of three different classes of wet friction materials were measured by a recently developed automated pore permeameter. Darcy's Law for laminar flow through homogenous porous media can be used to describe the anisotropic liquid permeability of wet friction materials. The elastic deformation of the three classes of wet friction materials was also determined. It was found that both the anisotropic liquid permeability and elastic deformation behaviors are important in affecting the durability of polymeric wet friction composite materials.