Author ORCID Identifier
Date Available
3-7-2025
Year of Publication
2025
Document Type
Master's Thesis
Degree Name
Master of Science in Mechanical Engineering (MSME)
College
Engineering
Department/School/Program
Mechanical Engineering
Advisor
Dr. Lyndon Scott Stephens
Abstract
A numerical analysis was conducted to investigate the viscoelastic effects of nonlinear materials on the sealing zone and contact pressure distribution of radial lip seals in a conventional geometric topology. The use of nonlinear materials in radial lip seal applications is desirable to improve operation and reliability of rotating machinery due to their high operating temperatures, chemical compatibility, and low friction coefficients. Examples include, but are not limited to, seals within industrial air compressors, turbine engines, aircraft landing systems, chemical processing equipment, and Freon pumps. This work focuses on analyzing the nonlinear viscoelastic response of pure Polytetrafluoroethylene (PTFE) and PTFE Glass MoS2 (GM) used in a radial lip seal used in railroad wheel bearings, subject to a specified radial shaft interference fit. A 2-D axisymmetric multi-scale finite element model (FEM) is developed that includes a railroad wheel bearing seal with a preload garter spring, rigid shaft, and contact elements along both regions of the sealing width. The viscoelastic effect is modeled using a two term Prony series that was obtained by curve fitting experimental relaxation modulus data obtained in previous work from Dynamic Mechanical Analysis (DMA) test data to the relative shear moduli. Results are presented showing the contact pressure distributions of varying scraper angles, barrel angles, garter spring stiffnesses, R-values, and the materials of interest. Discussion regarding the validity of the linear viscoelastic material assumption for pure PTFE and PTFE-GM is given. Regions of plasticity are identified for typical interference fits and recommendations are made for radial lip seal design parameters that result in non-plastic behavior, which is desirable from a sealing standpoint, and provide adequate sealing performance.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.05
Recommended Citation
Vogt, Madison, "ANALYSIS OF PTFE RADIAL LIP SEALS FOR WHEEL BEARING APPLICATIONS" (2025). Theses and Dissertations--Mechanical Engineering. 234.
https://uknowledge.uky.edu/me_etds/234
