Formula and Structure Effect of Frictional Materials on their Damping Properties and NVH Performance of Friction Joints

Fighting vibration and noise in vehicle brakes and transmissions consists today mainly in modifying design of friction joints, which involves alteration of the rubbing pair geometry or introduction of new damping elements into the structure, e.g. insulators. Although the beneficial effect of damping materials on brake NVH was supported by a large number of numerical and experimental investigations, the effect of composition and structure of frictional materials on their damping properties is still not explored adequately. The paper presents investigation results of the effect of composition and structure of frictional materials employed in brakes and transmissions on their dynamic properties and vibroacoustic activity of actual friction joints.

The results obtained present the dynamic properties of the materials depending on the type of polymer matrix, fiber filler orientation and dimensions, cure degree of the binder and the presence of plasticizer in the matrix phase. It has been found out that damping capacity of organic frictional materials depends strongly on their formula and structure and it tends to increase with temperature rise. The authors have elaborated the means of improving dynamic properties of frictional materials. The dynamometer tests of brakes and transmissions have also proved effective fighting of vibration and noise in friction joints via optimal choice of the formula and structure of frictional materials.