Effects of structural tests on aircraft safety [Conference Object]

Abstract

This paper investigates the effects of structural tests on aircraft safety. In particular, the paper focuses on the effect of the number of coupon tests and structural element tests on the final distribution of failure stress. The mean failure stress is assumed to be predicted by a failure criterion (e.g. Tsai-Wu), and the initial distribution of this mean failure stress reflects the uncertainty in the analysis procedure that uses coupon test data to predict structural failure. In addition to the uncertainty in the mean failure stress, there is also uncertainty in its variability due to the finite number of coupon tests. The Bayesian technique is used to update the failure stress distribution based on results of the element tests. Structural design following the FAA regulations is considered and the tradeoffs between the number of tests, weight and probability of failure in certification and in service are explored. We find that these are not very sensitive to the number of tests. Copyright © 2009 by E. Acar, R.T. Haftka and N.H. Kim.