PSI - Issue 23

Jan Poduška et al. / Procedia Structural Integrity 23 (2019) 293–298 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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If the crack started propagating directly in the middle layer made of the recycled PE, the lifetimes would be much shorter, but the pipe would still qualify almost as a PE80 pipe (must have a lifetime of 50 years at the hoop stress of 8 MPa). The change in the thickness of this layer affects the lifetimes only slightly (in case the layer is thicker the lifetime is a little longer, as the crack can propagate longer, and vice versa).

5. Conclusions

IT was proposed that the recycled PE could be used to form layers in multi-layer pipes. Lifetimes of these pipes were estimated by an approach based on linear elastic fracture mechanics to see, if the performance of the pipes is significantly influenced by the presence of a layer of recycled material. It can be concluded from the presented results that making a pressure pipe of the recycled PE only is not possible. However, the utilization of recycled PE in multi-layer pipes would not significantly lower the lifetime of the pipe, if the outer layers were made of virgin material with high SCG resistance. Results were obtained using equipment from the Large Infrastructures for Research, Experimental Development and Innovation - project IPMinfra, LM2015069. The research was also funded from the COMET PCCL K1 – Center in Polymer Engineering and Science – a COMET-program of the Federal Ministry for Transport, Innovation, and Technology, and the Federal Ministry for Economy, Family, and Youth with contributions by the Department of Polymer Engineering and Science, University of Leoben (Austria). The PCCL is funded by the Austrian government and the state governments of Styria and Upper Austria. Calton, T. 2016. The European Plastic Pipes Industry – Recycling Commitment. Plastics Pipes XVIII. Berlin, Germany. Cruz, S. A., Zanin M., 2003. Evaluation and Identification of Degradative Processes in Post-Consumer Recycled High-Density Polyethylene. Polymer Degradation and Stability 80 (1), 31 – 37. https://doi.org/10.1016/S0141-3910(02)00379-8. Frank, A., Arbeiter, F.,Berger, I.,Hutař, P., Náhlík, L., Pinter , G., 2019. Fracture Mechanics Lifetime Prediction of Polyethylene Pipes. Journal of Pipeline Systems Engineering and Practice 10 (1), 1 – 14. https://doi.org/10.1061/(ASCE)PS.1949-1204.0000356. Frank, A., Berger, I., Arbeiter, F., Pinter, G., 2017. The Cyclic Cracked Round Bar Test as a New Standard for Accelerated Material Ranking of Polyethylene Pipe Grades. Annual Technical Conference - ANTEC, Anaheim, USA, Conference Proceedings 1976 – 1981. Hutař, P., Ševčík , M. ,Náhlík, L., Pinter, G., Frank, A., Mitev, I., 2011. A Numerical Methodology for Lifetime Estimation of HDPE Pressure Pipes. Engineering Fracture Mechanics 78 (17), 3049 – 3058. https://doi.org/10.1016/j.engfracmech.2011.09.001. ISO 18489: Polyethylene (PE) Materials for Piping Systems -- Determination of Resistance to Slow Crack Growth under Cyclic Loading -- Cracked Round Bar Test Method. 2015. Jin, H., Gonzalez-Gutierrez, J., Oblak, P., Zupančič, B., Emri, I., 2012. The Effect of Extensive Mechanical Recycling on the Properties of Low Density Polyethylene. Polymer Degradation and Stability 97 (11): 2262 – 2272. https://doi.org/10.1016/j.polymdegradstab.2012.07.039. Kratochvilla, T. R., Frank, A., Pinter, G., 2014. Determination of Slow Crack Growth Behaviour of Polyethylene Pressure Pipes with Cracked Round Bar Test. Polymer Testing 40 (December), 299 – 303. https://doi.org/10.1016/j.polymertesting.2014.10.002. Navratil, J., Manas, M., Mizera, A., Bednarik, M., Stanek, M., Danek, M., 2015. Recycling of Irradiated High-Density Polyethylene. Radiation Physics and Chemistry 106: 68 – 72. https://doi.org/10.1016/j.radphyschem.2014.06.025. Reis, J. M. L., Pacheco, L. J., Da Costa Mattos, H. S., 2013. Tensile Behavior of Post-Consumer Recycled High-Density Polyethylene at Different Strain Rates. Polymer Testing 32 (2): 338 – 342. https://doi.org/10.1016/j.polymertesting.2012.11.007. Singh, N., Hui, D., Singh, R., Ahuja, I. P. S., Feo, L., Fraternali, F., 2017. Recycling of Plastic Solid Waste: A State of Art Review and Future Applications. Composites Part B: Engineering 115, 409 – 422. https://doi.org/10.1016/j.compositesb.2016.09.013. Acknowledgements References