New Metrics for Evaluating Monte Carlo Tolerance Analysis of Assemblies

Monte Carlo simulation may be used by engineering designers to predict the effects of manufacturing variations in mechanical assemblies. Validity of the predictions depends on the accuracy of the input variations, simulation sample size and the fit of a statistical distribution to the resultant assembly data. New metrics are presented for assessing the accuracy of variation analysis methods. Errors due to sample size are estimated for the mean, variance, skewness and kurtosis of the resultant distribution, and the predicted rejects. Simple algebraic expressions are derived, which can be used to predict the error in the assembly variation parameters without having to repeat the simulation.