Statistical analysis of the mechanical properties of composite materials

The Weibull statistic is currently used in designing mechanical components made of composite materials. This work presents useful formulae to describe the behaviour of the Weibull modulus estimator, which in turn may be described by means of a three-parameter Weibull distribution. Expressions for the parameters of this latter distribution, dependent on the sample size, are also given in the paper, so, the percentage points, published until now in tabular form, may be directly calculated. Empirical expressions are derived for determining the A-basis and the B-basis material properties as a function of the sample size.