Testing of Automotive Hub Units

Methods are described for the testing of automotive hub units under quasi-static, impact, and dynamic conditions. It is shown that the overall time required to reliably determine the rolling contact fatigue life of such units can be reduced by the selection of a suitable test strategy. A strategy is described in which fifteen ‘sudden death’ groups of four units are tested simultaneously. When any one unit in a group fails, then the complete group is considered to have failed. Weibull analysis is then applied to these results to estimate the L₁₀ life of the unit. This ‘sudden death’ strategy has a better discriminating power than a conventional ‘five failures from ten tested units’ strategy, and can be completed in a much shorter test time.