Effect of uncertainty in characterization on the variability of fibre strength distributions

International audienceAccuracy of strength models for composite material applications is dependent on the accuracy of the input data for its constituents, namely fibre and matrix properties[1].Any errors or variability in constituent properties would lead to inaccurate or variable model predictions. In practicethe characterization of fibre properties have been known to be very challenging, due to their small cross-sections, inhomogeneity, morphological variations, etc. which may lead to variations in the results[2]. Fibre properties reported in the literature are usually not consistent, mainly due to these challenges. The variation is even larger for very brittle materials such as carbon fibres which are one of the most popular reinforcements for composites[3]. These challenges directly affect determination of fibre properties especiallystrength which isthus strongly dependent on measurement accuracy[4]. No measurement is perfectly accurate and there is some degree of uncertainty associated with every result. Uncertainties can arise from many sources such as limited precision of measurement tool, the individual performing the measurement, etc.[5, 6]. The work described here aims at understanding the influence that measurement errors can have on the calculated strengthof carbon and glass fibres and their corresponding strength distributions. This would help in identifying the critical parameters which strongly affect strength and modulus measurements and lead to uncertainty. Minimising the effect of these parameters may significantly improve the accuracy of determined results.REFERENCES:[1] F. Islam, S. Joannes, and L. Laiarinandrasana,Evaluation of critical parameters in tensile strengthmeasurement of single fibres,Journal of Composites Science, 3 (3), 69.[2] J.L. Thomason. “On the application of weibull analysis to experimentally determined single fibre strength distributions”. Composites Science and Technology, Vol. pp 77:74 –80, 2013.[3] S.Joannès,F.Islam, L.Laiarinandrasana,. Uncertainty in fibre strength characterisationdue to uncertainty in measurement and samplingrandomness,Applied Composite Materials.[4] F. Islam, S. Joannes, and L. Laiarinandrasana,Investigation of tensilestrength anddimensional variationof T700 carbon fibresusing an improvedexperimentalsetup, Journal of Reinforced Plastics and Composites.[5] F.Islam, S.Bucknell, Y.Leray, A.Bunsell, L.Laiarinandrasana, S.Joannès. Improvements in determination of carbon fibre strength distribution using automation and statistical data analysis. Fiber Society's Spring Conference 2018, Jun 2018, Tokyo, Japan. 3 p. ⟨hal-01959309⟩.[6] F.Islam, S.Joannès, S.Bucknell, Y.Leray, A.Bunsell, L. Laiarinandrasana,Towardsaccurate and efficient single fibre characterization to better assess failure strength distribution. ECCM 18 -18th European conference on composite materials, Jun 2018, Athenes, Greece. 7 p. ⟨hal-01958211