Title: The Effect of Material Variability on the Pre-Gelation Behaviour of Prepreg Composites

Authors: Caitlin Duffner, Navid Zobeiry and Anoush Poursartip

DOI: 10.33599/nasampe/s.20.0154

Abstract: Processes such as forming and AFP have become increasingly popular, and these manufacturing techniques require manipulation of the uncured pre-impregnated thermoset matrix composite material (prepreg). Interest in the initial state or pre-gelation behaviour of prepregs has grown due to these manufacturing trends as well as the increasing recent research connecting this regime to processing defects such as wrinkling and porosity. Historically, the pre-gelation behaviour of prepreg has been relatively unexplored due to the challenges that traditional testing methods have in handling the soft raw prepreg. It is shown here that Digital Image Correlation (DIC) can capture the prepreg behaviour through the entirety of a cure cycle on both a local and global level. This work presents the global response of the prepreg, showing the true pre-gelation response, which differs markedly from what has traditionally been presented as the expected behaviour. Additionally, the variability in local prepreg response can be linked back to local strain variations observed using DIC. With the insight into the variability of a ply and the pre-gelation strain response, the findings in this work emphasize the importance of understanding and accurately capturing the initial prepreg condition.

References: 1. Stewart AL, Poursartip A. 2018."Characterization of fibre alignment in as-received aerospace grade unidirectional prepreg". Compos Part A Appl Sci Manuf 2018;112:239–49. doi:10.1016/j.compositesa.2018.04.018. 2. Mohseni SM, Fernlund G, Lane M. 2018."Cure cycle design to suppress moisture-driven bubble growth in polymer composites". J Compos Mater 2018;52:1821–32. doi:10.1177/0021998317734393. 3. Stewart AL. 2018.Misalignment defects in unidirectional composite materials. The University of British Columbia, 2018. doi:10.14288/1.0375794. 4. Garstka T, Ersoy N, Potter KDD, Wisnom MRR. 2007."In situ measurements of through-the-thickness strains during processing of AS4/8552 composite". Compos Part A Appl Sci Manuf 2007;38:2517–26. doi:10.1016/j.compositesa.2007.07.018. 5. Duffner C. 2019."Experimental Study of the Pre-gelation Behaviour of Composite Prepreg" 2019. doi:10.14288/1.0387323. 6. HEXCEL. 2016."HexPly® 8552 Product Data Sheet". Hexcel 2016:1–6. 7. Van Ee D, Poursartip A. 2009."NCAMP Hexply Material Properties Database for use with COMPRO CCA and Raven". Natl Cent Adv Mater Perform 2009:141. 8. Convergent Manufacturing. 2017."RAVEN simulation software" 2017. http://www.convergent.ca/products/raven-simulation-software. 9. Mehdikhani M, Aravand M, Sabuncuoglu B, Callens MG, Lomov S V., Gorbatikh L. 2016."Full-field strain measurements at the micro-scale in fiber-reinforced composites using digital image correlation". Compos Struct 2016;140:192–201. doi:10.1016/j.compstruct.2015.12.020. 10. Knowles KR, Tu J, Wiggins JS. 2017."Thermal and volumetric property analysis of polymer networks and composites using elevated temperature digital image correlation". Polym Test 2017;58:48–53. doi:10.1016/j.polymertesting.2016.12.013. 11. Heinz SR, Wiggins JS. 2010."Uniaxial compression analysis of glassy polymer networks using digital image correlation". Polym Test 2010;29:925–32. doi:10.1016/j.polymertesting.2010.08.001. 12. Bing P, Hui-min X, Tao H, Asundi A. 2009."Measurement of coefficient of thermal expansion of films using digital image correlation method". Polym Test 2009;28:75–83. doi:10.1016/j.polymertesting.2008.11.004. 13. Jerabek M, Major Z, Lang RW. 2010."Strain determination of polymeric materials using digital image correlation". Polym Test 2010;29:407–16. doi:10.1016/j.polymertesting.2010.01.005. 14. Jackson MB, Heinz SR, Wiggins JS. 2012."Fluid ingress strain analysis of glassy polymer networks using digital image correlation". Polym Test 2012;31:1131–9. doi:10.1016/j.polymertesting.2012.08.007. 15. Zobeiry N, Vaziri R, Poursartip A. 2015."Characterization of strain-softening behaviour and failure mechanisms of composites under tension and compression". Compos Part A Appl Sci Manuf 2015:29–41. 16. Rust-Oleum Consumer Brands Canada. 2015.Rust-Oleum White Safety Data Sheet. 17. Products Krylon. 2019.KRYLON® Camouflage Paint Black-Safety data sheet. 18. Mobuchon C, Poursartip A. 2019."Linear dependences of the cure shrinkage and thermal expansion of thermoset polymers on degree of cure", unpublished work. 19. Mobuchon C, Zobeiry N, Duffner C, Poursartip A. 2018."A Multifaceted Approach for Process Characterization of Polymer- matrix Composites". 12th Canada-Japan Work. Compos., Takayama: , p. 1–8. 20. Chatterjee S. 2014."Thermo-mechanical characterization of 8552 resin and AS4/8552 prepreg", unpublished work. 21. Zobeiry N, Duffner C. 2018."Measuring the negative pressure during processing of advanced composites". Compos Struct 2018;203:11–7. doi:10.1016/j.compstruct.2018.06.123. 22. DUFFNER C, ZOBEIRY N, POURSARTIP A. 2018."Examination of Pre-gelation Behavior in AS4/8552 Prepreg Composites". Am. Soc. Compos. 2018, . doi:10.12783/asc33/25974. 23. Ersoy N, Garstka T, Potter K, Wisnom MR, Porter D, Clegg M, et al. 2010."Development of the properties of a carbon fibre reinforced thermosetting composite through cure". Compos Part A Appl Sci Manuf 2010;41:401–9. doi:10.1016/j.compositesa.2009.11.007. 24. Duffner, C, Courteau-Godmaire H, Zobeiry N, Poursartip A. 2019."Characterization of Prepreg Initial Morphology". 11th Can. Conf. Compos, Kelowna, July 2019.

Conference: SAMPE 2020 | Virtual Series

Publication Date: 2020/06/01

SKU: TP20-0000000154

Pages: 12

Price: FREE