Grease material properties from first principles thermodynamics

Jude A. Osara*, Sathwik Chatra, Piet M. Lugt

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

3 Citations (Scopus)
2 Downloads (Pure)

Abstract

Thermodynamics has historically been used to derive characteristic material properties. In this study, fundamental thermodynamics is applied to grease. First-principle formulations of existing material properties—heat capacity and storage modulus—and new properties—thermal strain and stress coefficients, chemical resistance and thermo-chemical decay coefficient—are derived, some of which are experimentally determined. A new group of Maxwell relations is introduced by replacing the classical compression work (Formula presented.) with the grease shearing work (Formula presented.). The physical interpretations and implications of these properties on grease behaviour and performance are presented. Experimental measurements of the derived properties are performed in accordance with the theoretical formulations. Six different grease types are studied. Obtained results are shown to conform with anticipated, observed and established grease behaviours. The proposed properties can be used in grease performance and degradation analyses, as well as grease selection for lubrication applications.

Original languageEnglish
Pages (from-to)36-50
Number of pages15
JournalLubrication science
Volume36
Issue number1
DOIs
Publication statusPublished - Jan 2024

Keywords

  • UT-Hybrid-D
  • grease properties
  • lubricating grease
  • rolling bearings
  • thermodynamics
  • grease life

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