Relaxation of Thermoplastic Rotary Shaft Seals

In order to use the finite elements efficiently in the design of PTFE seals at an early stage a suitable material model is a basic requirement. To the knowledge of the authors such a material model is not yet commercially available.

So a typical polytetrafluorethylen (PTFE) compound with glass fiber and other fillers has been investigated. This type of compound is extensively used for main lip rotary shaft seals.

Material properties like stress-strain characteristics and relaxation under traction- and compression load were measured at various temperatures and their dependence on time was analyzed.

A material model was developed to be implemented into FE-programs.

Calculated and measured values of the radial load of shaft seals with varying loading over time were compared and prove the reliability of the proposed material model.