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Report of NADDRG Friction Committee on Reproducibility of Friction Tests within and Between Laboratories
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Abstract
The present paper offers a status report on round-robin tests conducted with the participation of ten laboratories, with drawbead simulation (DBS) as the test method. The results showed that, in most laboratories, the coefficient of friction (COF) derived from the test is repeatable within an acceptable range of ±0.01. Repeatability between laboratories was less satisfactory. Five laboratories reported results within the desirable band, while some laboratories found consistently higher values. In one instance this could be traced to incomplete transfer of clamp forces to the load cell, in other instances inaccurate test geometry is suspected. Therefore, numerical values of COF from different laboratories are not necessarily comparable. Irrespective of these inter-laboratory variations, the relative ranking of lubricants was not affected, and data generated within one laboratory can be used for relative evaluations and for a resolution of production problems. A further round robin is planned once the instrumentation and test geometry of all laboratories are brought into agreement.
Citation
Schey, J. and Smith, M., "Report of NADDRG Friction Committee on Reproducibility of Friction Tests within and Between Laboratories," SAE Technical Paper 930811, 1993, https://doi.org/10.4271/930811.Also In
References
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- Dalton G.M. University of Waterloo Internal Report 1991 Oct. 10
- Schey J.A. Geometric Factors Affecting Results from the Drawbead Simulation (DBS) Test
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