PSI - Issue 18

G. Quino et al. / Procedia Structural Integrity 18 (2019) 507–515

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G. Quino et. al/ Structural Integrity Procedia 00 (2019) 000–000

The residual is plotted with respect to the strain in Fig. 8. It is evident that the SM-obtained apparent distribution of strengths does not only provide an input for the model that leads to more realistic results, but also provides an output quantitatively closer to the real measurements. To make this point stronger the coefficient of determination � was computed between experimental curve, and the Weibull and the SM Apparent distribution models, obtaining 0.9102, and 0.9608 respectively. Thus, confirming the improvements of the model when relying on the SM obtained apparent strength distribution.

Fig. 8. Residuals from the two numerical experiments.

An important limitation observed in this study was the inability of the method to capture as many SM events as fibres within the bundle. More work is still needed to improve the methodology for calibration of the criteria to identify each SM event. 6. Concluding remarks and future work In this paper we explored the application of sound measurements (SM) on fibre bundles. The information obtained from the sound emitted when fibre break has shown that:  This technique has the capability of detecting the initiation and progression of failure with low cost and ease of implementation.  SM allows to reconstruct a set of values for “apparent strengths” that can act as an input for models. In this way, they provide results closer to the experimental evidence and with more realistic features, in contrast to what is obtained with approach of the Weibull set of strengths. Further work is still required to improve the way the threshold is chosen to try to capture all the failure events. Future directions of research should also explore the applicability of the method on other type of materials and fibre breaking detection within fibre reinforced composites. Acknowledgements The authors acknowledge the support of the Engineering Science Department, University of Oxford.