Paper number 675

IMPROVEMENT OF UNIDIRECTIONAL COMPOSITE STRENGTH PROBABILISTIC MODEL

Chris M. Boyer

Département Mécanique des Systèmes, Faculté Léonard De Vinci
92 916 Paris La Défense, Chris.Boyer@devinci.fr

Summary

This article presents improvements on unidirectional composite strength probabilistic model. This paper shows how to increase the preciseness of simulation, first by using a simple mechanical model to predict the load transfer around fibre breaks, and secondly by developing the probabilistic equations at the second order. From experimental multifragmentation test results and due to these improvements, the model is able to give the mean of the composite strength with an error of 8 % instead of 40 %. Nevertheless the model which is dedicated to predict also the strength scattering, underestimates it highly. That asks about the real origin of the scattering of unidirectional strength, underlining the testing problems and the design rules which take into account the reliability and the scale effect.

Keywords

unidirectional, load transfer, strength probabilistic model, mean, standard deviation, ineffective length.