PSI - Issue 17

Siegfried Frankl et al. / Procedia Structural Integrity 17 (2019) 51–57 Siegfried Frankl / Structural Integrity Pro edi 00 (2019) 000 – 000

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Fig. 7: Results for the incremental crack propagation model with different friction coefficients µ 1 , µ 2 showing (a) the strain energy U , (b) the crack length a and (c) the tensile force F plotted over the applied displacement u .

4. Conclusions

A model for predicting incremental crack growth of a fibre bundle pulled out of a rubber block was developed. The energy release rate G for a delamination crack is computed from energetic consideration of two models with different crack lengths. A mesh size that is sufficiently small for an accurate computation of G values has been identified. Computation times for that mesh size amount to about 2 minutes on a common desktop computer. From looking at the energy values, the contribution of the frictional dissipation for the calculation of G can be disregarded. For the incremental crack propagation model, previously run finite element models with various crack lengths were used to predict how the crack propagates with an applied displacement load. Depending on geometric parameters, material properties and fracture energy G c , force-displacement curves can be computed for the fibre pull-out test. In future work, the G c values will be fitted to test curves and the method for computing delamination crack growth can be extended to realistic applications with more complex geometry and competing damage modes, for example the possibility for the crack to deflect into the rubber part.

Acknowledgements

The funding of the research by the Austrian Research Promotion Agency, FFG, through the Project BeltSim within the Bridge 1 program is gratefully acknowledged.

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