A simple and accurate method to calculate transient ehl film thickness in machine components undergoing operation cycles

L. Chang

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

This paper presents a new method to calculate EHL film thicknesses for contacts operating in transient conditions. The method approximates the EHL pressure distribution by its corresponding Hertz distribution. The transient Reynolds equation is simplified to a partial differential equation governing wave propagation of the film thickness from the inlet to the outlet of the Hertz contact region. The film thickness at the Hertz inlet is calculated by the Dowson-Toyoda formula in which the parameters are determined by the current operating conditions. These modeling techniques greatly enhance the robustness and computational efficiency of the method. A wide range of practical EHL problems can be solved, and film thicknesses for a full cycle of machine operation can be calculated on a PC in a few seconds of CPU time. The accuracy of the method is evaluated by comparing its results with those obtained by a full transient EHL model. The comparison is fairly favorable for a wide range of operating conditions with large variations of load and speed parameters and with a frequency of variation up to 1000 cycles per second. This method of transient film thickness calculations can be easily implemented into design programs for EHL machine elements. it also establishes a platform upon which other design calculations and analyses can be performed such as asperity contacts, temperature and traction.

Original languageEnglish (US)
Pages (from-to)116-122
Number of pages7
JournalTribology Transactions
Volume43
Issue number1
DOIs
StatePublished - Jan 1 2000

Fingerprint

Machine components
Film thickness
film thickness
cycles
Reynolds equation
traction
outlets
Computational efficiency
pressure distribution
Pressure distribution
partial differential equations
Wave propagation
Partial differential equations
Program processors
wave propagation
platforms
Temperature
temperature

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Cite this

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abstract = "This paper presents a new method to calculate EHL film thicknesses for contacts operating in transient conditions. The method approximates the EHL pressure distribution by its corresponding Hertz distribution. The transient Reynolds equation is simplified to a partial differential equation governing wave propagation of the film thickness from the inlet to the outlet of the Hertz contact region. The film thickness at the Hertz inlet is calculated by the Dowson-Toyoda formula in which the parameters are determined by the current operating conditions. These modeling techniques greatly enhance the robustness and computational efficiency of the method. A wide range of practical EHL problems can be solved, and film thicknesses for a full cycle of machine operation can be calculated on a PC in a few seconds of CPU time. The accuracy of the method is evaluated by comparing its results with those obtained by a full transient EHL model. The comparison is fairly favorable for a wide range of operating conditions with large variations of load and speed parameters and with a frequency of variation up to 1000 cycles per second. This method of transient film thickness calculations can be easily implemented into design programs for EHL machine elements. it also establishes a platform upon which other design calculations and analyses can be performed such as asperity contacts, temperature and traction.",
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A simple and accurate method to calculate transient ehl film thickness in machine components undergoing operation cycles. / Chang, L.

In: Tribology Transactions, Vol. 43, No. 1, 01.01.2000, p. 116-122.

Research output: Contribution to journalArticle

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