Approximate interval estimates for mechanical reliability

Abstract

Two approximate interval estimation procedures for mechanical component reliability, P(XY), are developed and their accuracy evaluated by computer simulations. The strength, X, of the component and the stress, Y, applied to it are independent normally distributed variables with unknown means and variances. In the first interval procedure the variances are equal. In the second procedure the variances may be unequal. The derived intervals are quite accurate for the cases simulated which include large and small sample sizes. These procedures are simple to apply and require the use of percentile points of the Student's distribution. In the second procedure, the degrees of freedom of the associated t statistic is a function of the test data, and therefore it is random.