Squeak and Rattle Behavior of Filled Thermoplastics: Effect of Filler Type and Content on Acoustic Behavior 2005-01-2542

As the use of thermoplastics, for interior and exterior automotive components, increases there is a risk of combining two frictionally incompatible materials, resulting in a noise such as a squeak, tick, chirp… When material pairs undergo sliding contact, friction forces can cause elastic deformation of components adjacent to the contacting surfaces. The elastic deformation is a mechanism for storing energy and when released, audible sound is produced. The sound that is heard may be a squeak (multiple stick slips (MSS)) or a tick (single stick slip (SSS)) either or which is perceived as unexpected and objectionable. However if the sliding material composition (e.g. coatings, low friction additives…) and the structure (amount of stiffness or compliance) of the sliding components can be properly selected, we can avoid an unwanted noise situation.

To provide engineering information to Forward Model Design Engineers, friction (squeak) and rattle testers have been used to measure audible noise, as a function of sliding velocity, normal load, surface roughness, filler type and amount, and random impact properties.