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Influence of stitching on the interlaminar fracture toughness energy – modes I and II – of unidirectional GFRP

  • Simon Backens

    Dr.-Ing. Simon Backens, born in 1990, studied mechanical engineering at the TU Kaiserslautern. Since 2016, he has been a research assistant at the Fraunhofer Institute for Large Structures in Production Engineering IGP in Rostock. He works in the Fiber Composite Technology Group of the New Materials and Processes Department. In 2024, he completed his doctorate on the topic of “ Recycling of carbon fiber-reinforced plastics with subcritical water.”

     EMAIL logo     , Stefan Schmidt

    Dr.-Ing. Stefan Schmidt, born in 1988, studied mechanical engineering at the University of Rostock and has been working at the Fraunhofer Institute for Large Structures in Production Engineering IGP in Rostock since 2014. In 2020, he completed his doctorate on the topic of “Structural bonding of fiber-reinforced plastic composites.” Since 2020, he is group leader of the Fiber Composite Technology Group.

         and Wilko Flügge

    Prof. Dr.-Ing. Wilko Flügge, born in 1969, studied mechanical engineering at the TU Clausthal. At the University of Paderborn, he completed his doctorate on the subject of “Punch riveting of stainless steels.” Until 2017, he worked in research in the field of application technology at Salzgitter AG. Since June 2017, he has been chair holder of the Chair of Production Engineering at the University of Rostock and head of the Fraunhofer Institute for Large Structures in Production Engineering IGP.
Published/Copyright: November 6, 2024
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Materials Testing
From the journal Materials Testing Volume 66 Issue 12

Abstract

The influence of stitching on the delamination resistance of unidirectional glass fiber-reinforced plastic laminates depends strongly on the loading mode. The application of a lock stitch with a stitch density of 3.4 cm−1 perpendicular to the fibers results in an increase of the interlaminar fracture toughness energy, mode I, G IC by a factor of 2.7 compared to an unstitched reference laminate. The Kevlar threads are pulled out of one half of the DCB specimen leaving large frayed fiber bundles sticking out of the other half. The same stitching, however, does not improve the interlaminar fracture toughness energy, mode II, G IIC. The Kevlar threads are not able to deform the surrounding matrix thereby expending additional energy. They fail directly at the mid-plane of the ENF specimens. An increased stitch density of 11.6 cm−1 can be expected to lead to a further significant increase in the G IC value. But the tight stitching pattern causes the bonded metal hinges to tear off. The force introduction would have to be changed to enable testing of corresponding DCB and subsequently ENF specimens.

Keywords: double cantilever beam; end notch flexure; glass fiber reinforced plastic; Kevlar stitching; lock stitch
Corresponding author: Simon Backens, Department of New Materials and Processes, Fraunhofer Institute for Large Structures in Production Engineering IGP, Albert-Einstein-Straße 30, 18059 Rostock, Germany, E-mail:

About the authors

Simon Backens

Dr.-Ing. Simon Backens, born in 1990, studied mechanical engineering at the TU Kaiserslautern. Since 2016, he has been a research assistant at the Fraunhofer Institute for Large Structures in Production Engineering IGP in Rostock. He works in the Fiber Composite Technology Group of the New Materials and Processes Department. In 2024, he completed his doctorate on the topic of “ Recycling of carbon fiber-reinforced plastics with subcritical water.”

Stefan Schmidt

Dr.-Ing. Stefan Schmidt, born in 1988, studied mechanical engineering at the University of Rostock and has been working at the Fraunhofer Institute for Large Structures in Production Engineering IGP in Rostock since 2014. In 2020, he completed his doctorate on the topic of “Structural bonding of fiber-reinforced plastic composites.” Since 2020, he is group leader of the Fiber Composite Technology Group.

Wilko Flügge

Prof. Dr.-Ing. Wilko Flügge, born in 1969, studied mechanical engineering at the TU Clausthal. At the University of Paderborn, he completed his doctorate on the subject of “Punch riveting of stainless steels.” Until 2017, he worked in research in the field of application technology at Salzgitter AG. Since June 2017, he has been chair holder of the Chair of Production Engineering at the University of Rostock and head of the Fraunhofer Institute for Large Structures in Production Engineering IGP.

Acknowledgments

The authors thank Laurens Nagel for manufacturing the GFRP laminates and carrying out the tests. They thank Kathrin Hasche, Nadine Reschke and Viktoria Nikolova (all New Materials and Processes, Fraunhofer IGP) for determining the fiber volume contents, taking the images of the fracture patterns and their support during manufacturing. Their thanks also go to Nordex Energy SE & Co. KG for providing the epoxy resin and the glass fibers.

  1. Research ethics: Not applicable.

  2. Informed consent: Not applicable.

  3. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Use of Large Language Models, AI and Machine Learning Tools: None declared.

  5. Conflict of interest: The authors state no conflict of interest.

  6. Research funding: None declared.

  7. Data availability: The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

References

[1] R. Rikards, A. Korjakin, F. G. Buchholz, H. Wang, A. K. Bledzki, and G. Wacker, “Interlaminar fracture toughness of GFRP influenced by fiber surface treatment,” J. Compos. Mater., vol. 32, no. 17, pp. 1528–1559, 1998. https://doi.org/10.1177/002199839803201701.Search in Google Scholar

[2] R. Rikards, F.-G. Buchholz, A. K. Bledzki, G. Wacker, and A. Korjakin, “Mode I, mode II, and mixed-mode I/II interlaminar fracture toughness of GFRP influenced by fiber surface treatment,” Mech. Compos. Mater., vol. 32, no. 5, pp. 439–462, 1996. https://doi.org/10.1007/BF02313863.Search in Google Scholar

[3] P. Robinson and J. M. Hodgkinson, “Interlaminar fracture toughness,” in Mechanical Testing of Advanced Fibre Composites, J. M. Hodgkinson, Ed., Cambridge, England, Boca Raton, FL, USA, Woodhead Publishing Limited, CRC Press, 2000. Ch. 9, pp. 170–210.10.1533/9781855738911.170Search in Google Scholar

[4] A. P. Mouritz, “Three-dimensional (3D) fibre reinforcements for composites,” in Composite Reinforcements for Optimum Performance, P. Boisse, Ed., Cambridge, England, Woodhead Publishing Limited, 2011. Ch. 6, pp. 157–199.10.1533/9780857093714.2.157Search in Google Scholar

[5] A. P. Mouritz, M. K. Bannister, P. J. Falzon, and K. H. Leong, “Review of applications for advanced three-dimensional fibre textile composites,” Composites, Part A, vol. 30, no. 12, pp. 1445–1461, 1999. https://doi.org/10.1016/S1359-835X(99)00034-2.Search in Google Scholar

[6] A. P. Mouritz, K. H. Leong, and I. Herszberg, “A review of the effect of stitching on the in-plane mechanical properties of fibre-reinforced polymer composites,” Composites, Part A, vol. 28, no. 12, pp. 979–991, 1997. https://doi.org/10.1016/S1359-835X(97)00057-2.Search in Google Scholar

[7] K. Dransfield, C. Baillie, and Y.-W. Mai, “Improving the delamination resistance of CFRP by stitching - a review,” Compos. Sci. Technol., vol. 50, no. 3, pp. 305–317, 1994. https://doi.org/10.1016/0266-3538(94)90019-1.Search in Google Scholar

[8] K. A. Dransfield, L. K. Jain, and Y.-W. Mai, “On the effects of stitching in CFRPs—I. mode I delamination toughness,” Compos. Sci. Technol., vol. 58, no. 6, pp. 815–827, 1998. https://doi.org/10.1016/S0266-3538(97)00229-7.Search in Google Scholar

[9] L. K. Jain, K. A. Dransfield, and Y.-W. Mai, “Effect of reinforcing tabs on the mode I delamination toughness of stitched CFRPs,” J. Compos. Mater., vol. 32, no. 22, pp. 2016–2041, 1998. https://doi.org/10.1177/002199839803202202.Search in Google Scholar

[10] L. K. Jain, K. A. Dransfield, and Y.-W. Mai, “On the effects of stitching in CFRPs—II. Mode II delamination toughness,” Compos. Sci. Technol., vol. 58, no. 6, pp. 829–837, 1998. https://doi.org/10.1016/S0266-3538(97)00186-3.Search in Google Scholar

[11] K. P. Plain and L. Tong, “An experimental study on mode I and II fracture toughness of laminates stitched with a one-sided stitching technique,” Composites, Part A, vol. 42, no. 2, pp. 203–210, 2011. https://doi.org/10.1016/j.compositesa.2010.11.006.Search in Google Scholar

[12] Y. Iwahori, T. Ishikawa, N. Watanabe, A. Ito, Y. Hayashi, and S. Sugimoto, “Experimental investigation of interlaminar mechanical properties on carbon fiber stitched CFRP laminates,” Adv. Compos. Mater., vol. 16, no. 2, pp. 95–113, 2007. https://doi.org/10.1163/156855107780918973.Search in Google Scholar

[13] N. R. Abdelal and S. L. Donaldson, “The effect of Nylon and kevlar stitching on the mode I fracture of carbon/epoxy composites,” Int. J. Mech. Ind. Aerosp. Eng., vol. 12, no. 4, pp. 347–352, 2018. https://doi.org/10.5281/zenodo.1316269.Search in Google Scholar

[14] N. R. Abdelal and S. L. Donaldson, “The effect of stitching with conductive and nonconductive materials on the mode I interlaminar fracture toughness of carbon fiber composites,” Polym. Compos., vol. 40, no. S2, pp. E1252–E1262, 2019. https://doi.org/10.1002/pc.24958.Search in Google Scholar

[15] A. Shah, D. A. Drake, and R. W. Sullivan, “Fracture toughness of stitched CFRP composites using optical fiber strains,” in 35th Tech. Conf. of the ASC. [Online], 2020.10.12783/asc35/34860Search in Google Scholar

[16] S. K. Sharma and B. V. Sankar, “Effect of stitching on impact and interlaminar properties of graphite/epoxy laminates,” J. Thermoplast. Compos. Mater., vol. 10, no. 3, pp. 241–253, 1997. https://doi.org/10.1177/089270579701000302.Search in Google Scholar

[17] W. Trabelsi, L. Michel, and R. Othomene, “Effects of stitching on delamination of satin weave carbon-epoxy laminates under mode I, mode II and mixed-mode I/II loadings,” Appl. Compos. Mater., vol. 17, no. 6, pp. 575–595, 2010. https://doi.org/10.1007/s10443-010-9128-0.Search in Google Scholar

[18] G.-C. Tsai and J.-W. Chen, “Effect of stitching on Mode I strain energy release rate,” Compos. Struct., vol. 69, no. 1, pp. 1–9, 2005. https://doi.org/10.1016/j.compstruct.2004.02.009.Search in Google Scholar

[19] H. P. Zhao, R. K. Y. Li, and X.-Q. Feng, “Experimental investigation of interlaminar fracture toughness of CFRP composites with different stitching patterns,” Key Eng. Mater., vols. 297–300, pp. 189–194, 2005. https://doi.org/10.4028/www.scientific.net/KEM.297-300.189.Search in Google Scholar

[20] R. Massabò, D. R. Mumm, and B. Cox, “Characterizing mode II delamination cracks in stitched composites,” Int. J. Fract., vol. 92, pp. 1–38, 1998. https://doi.org/10.1023/A:1007520324207.10.1023/A:1007520324207Search in Google Scholar

[21] B. V. Sankar and S. K. Sharma, “Mode II delamination toughness of stitched graphite/epoxy textile composites,” Compos. Sci. Technol., vol. 57, no. 7, pp. 729–737, 1997. https://doi.org/10.1016/S0266-3538(97)00032-8.Search in Google Scholar

[22] F. Aymerich, C. Pani, and P. Priolo, “Effect of stitching on the low-velocity impact response of [03/903]s graphite/epoxy laminates,” Composites, Part A, vol. 38, no. 4, pp. 1174–1182, 2007. https://doi.org/10.1016/j.compositesa.2006.06.005.Search in Google Scholar

[23] L. Francesconi and F. Aymerich, “Impact damage resistance of thin stitched carbon/epoxy laminates,” J. Phys.: Conf. Ser., vol. 628, 2015, Art. no. 012099. https://doi.org/10.1088/1742-6596/628/1/012099.Search in Google Scholar

[24] B. Liu, et al., “Experimental and numerical analysis of stitched composite laminates subjected to low-velocity edge-on impact and compression after edge-on impact,” Polymers, vol. 15, p. 2484, 2023. https://doi.org/10.3390/polym15112484.Search in Google Scholar PubMed PubMed Central

[25] V. Lopresto, V. Melito, C. Leone, and G. Caprino, “Effect of stitches on the impact behaviour of graphite/epoxy composites,” Compos. Sci. Technol., vol. 66, no. 2, pp. 206–214, 2006. https://doi.org/10.1016/j.compscitech.2005.04.029.Search in Google Scholar

[26] S. K. Sharma and B. V. Sankar, “Sublaminate buckling and compression strength of stitched uniweave graphite/epoxy laminates,” J. Reinf. Plast. Compos., vol. 16, no. 5, pp. 425–434, 1997. https://doi.org/10.1177/073168449701600503.Search in Google Scholar

[27] K. T. Tan, N. Watanabe, and Y. Iwahori, “Impact damage resistance, response, and mechanisms of laminated composites reinforced by through-thickness stitching,” Int. J. Damage Mech., vol. 21, no. 1, pp. 51–80, 2012. https://doi.org/10.1177/1056789510397070.Search in Google Scholar

[28] T. Rys, B. V. Sankar, and P. G. Ifju, “Investigation of fracture toughness of laminated stitched composites subjected to mixed mode loading,” J. Reinf. Plast. Compos., vol. 29, no. 3, pp. 422–430, 2010. https://doi.org/10.1177/0731684408099407.Search in Google Scholar

[29] R. Velmurugan and S. Solaimurugan, “Improvements in Mode I interlaminar fracture toughness and in-plane mechanical properties of stitched glass/polyester composites,” Compos. Sci. Technol., vol. 67, no. 1, pp. 61–69, 2007. https://doi.org/10.1016/j.compscitech.2006.03.032.Search in Google Scholar

[30] M. Tarfaoui and L. Hamitouche, “Mode I interlaminar fracture toughness of through-thickness reinforced laminated Structures,” Adv. Mater. Res., vol. 423, pp. 154–165, 2011. https://doi.org/10.4028/www.scientific.net/AMR.423.154.Search in Google Scholar

[31] R. Li, L. Ye, and Y.-W. Mai, “Interlaminar fracture of stitched GFRP laminates,” Adv. Compos. Lett., vol. 5, no. 1, pp. 5–8, 1996. https://doi.org/10.1177/096369359600500101.Search in Google Scholar

[32] S. Solaimurugan and R. Velmurugan, “Influence of in-plane fibre orientation on mode I interlaminar fracture toughness of stitched glass/polyester composites,” Compos. Sci. Technol., vol. 68, nos. 7–8, pp. 1742–1752, 2008. https://doi.org/10.1016/j.compscitech.2008.02.008.Search in Google Scholar

[33] D. Göktaş, W. R. Kennon, and P. Potluri, “Improvement of mode I interlaminar fracture toughness of stitched glass/epoxy composites,” Appl. Compos. Mater., vol. 24, no. 2, pp. 351–375, 2017. https://doi.org/10.1007/s10443-016-9560-x.Search in Google Scholar

[34] A. P. Mouritz and L. K. Jain, “Interlaminar fracture properties of stitched fibreglass composites,” in Proceedings of ICCM11, 1997, pp. 116–127.Search in Google Scholar

[35] S. Backens, S. Schmidt, and W. Flügge, “Influence of backing layers on the interlaminar fracture toughness energy – mode I – of quasi-unidirectional GFRP,” Mater. Test., vol. 66, no. 7, pp. 1031–1040, 2024. https://doi.org/10.1515/mt-2024-0020.Search in Google Scholar

[36] D. C. Hartlen, J. Montesano, and D. S. Cronin, “A composite rigid double cantilever beam specimen for assessing the traction–separation response of mode I delamination in composite laminates,” Exp. Mech., vol. 63, no. 8, pp. 1273–1283, 2023. https://doi.org/10.1007/s11340-023-00987-2.Search in Google Scholar
Published Online: 2024-11-06
Published in Print: 2024-12-17

© 2024 Walter de Gruyter GmbH, Berlin/Boston

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https://doi.org/10.1515/mt-2024-0208
Keywords for this article
double cantilever beam; end notch flexure; glass fiber reinforced plastic; Kevlar stitching; lock stitch

Articles in the same Issue

  1. Frontmatter
  2. Bending moment calibration for rotational bending fatigue testing machine based on strain measurement
  3. Structural monitoring of elevator guide rail bracket under normal running condition
  4. TiB-based coating formation on Ti6Al4V alloy
  5. Mechanical behavior of shape memory alloys considering the effects of body fluids corrosion for biomedical applications
  6. Impact of lattice designs and production parameters on mechanical properties of AlSi10Mg in laser powder bed fusion
  7. Effect of bio-waste conch filler addition on mechanical performance of glass fiber-reinforced epoxy polymer composite
  8. Effect of austempering temperatures on mechanical properties of dual matrix structure austempered ductile iron
  9. Influence of SiC content on the properties of Al/SiC composites produced by powder metallurgical route
  10. Effect of boron content and quenching temperature on the microstructure and wear resistance of high boron steel
  11. Influence of heat treatment on metallurgical and mechanical properties of aluminium Al6061 hybrid metal matrix composites
  12. Influence of stitching on the interlaminar fracture toughness energy – modes I and II – of unidirectional GFRP
  13. Hardfacing of GX40CrNiSi25-20 cast stainless steel with an austenitic manganese steel electrode
  14. Optimization and machinability evaluation for WEDM of austempered ductile iron
  15. Diffusion kinetics of borided of low entropy soft magnetic FeCo alloy
  16. Wear properties of Al6061/SiC + B4C + TiC hybrid composites produced by vacuum infiltration method
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