Abstract
Out-of-plane joints, between hat (omega) stiffeners and skin panels are asymmetric parts of the composite structure. Studies show that physical-mechanical conditions in these joints significantly affect skin forming quality. In the present article, aimed to investigate the mechanism of the skin wrinkle in the joints of carbon fiber reinforced plastics (CFRP) hat-shaped structure, the pressure testing apparatus based on the Pascal principle is used to surveillance the resin pressure dynamically in out-of-plane joints. In this regard, several influencing factors such as first-order holding time, forming pressure and relative volume of unidirectional fillers are studied. Obtained results show that increasing the first stage holding time can prolong the viscous flow state of the resin, and time to achieve pressure equalization at each detection point, thereby improving the dispersion of the pressure and reducing the possibility of wrinkles. It is found that as the forming pressure increases, the degree of skin wrinkles in the out-of-plane joints ameliorates. Moreover, for fillers with a relative volume within the range of 0–50%, the pressure transfer effect and the skin flatness is relatively dissatisfactory. It is concluded that the filler with a relative volume of 80–120% improves the skin wrinkle in out-of-plane joints.
Funding source: National Science Foundation of China
Award Identifier / Grant number: No. 51675538
Funding source: National Key Basic Research Program of China (973 program)
Award Identifier / Grant number: No. 2014CB46502
Acknowledgements
The authors would like to gratefully acknowledge the research team members of Central South University for their support and useful discussions in this research.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: This investigation was supported by funding from the National Key Basic Research Program of China (973 program) under grant no. 2014CB46502 and the National Science Foundation of China under grant no. 1675538.
Conflict of interest statement: The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
References
1. Zhang, H., Liu, M. Development and applications of carbon fiber reinforced polymer. Eng. Plast. Appl. 2015, 43, 132–135.Search in Google Scholar
2. Williams, J. K., Stein, M. Buckling behavior and structural efficiency of open-section stiffened composite compression panels. AIAA J. 1976, 14, 1618–1626. https://doi.org/10.2514/3.61497.Search in Google Scholar
3. Yokozeki, T., Takemura, H., Aoki, T. Numerical analysis on the flexural strength of unidirectional CFRTP composites with in-plane fiber bundle waviness. Adv. Compos. Mater. 2020, 29, 89–100. https://doi.org/10.1080/09243046.2019.1650322.Search in Google Scholar
4. Minakuchi, S., Sawaguchi, K., Takagaki, K., Niwa, S., Takeda, N. Effect of inter-laminar toughened layers on process-induced strain and deformation of L-shaped composites. Adv. Compos. Mater. 2019, 28, 445–461. https://doi.org/10.1080/09243046.2019.1573452.Search in Google Scholar
5. Ancelotti Jr, A. C., Pardini, L. C., Bezerra, E. M., Roach, D. Use of the mar-lin criteria to determine the influence of porosity on the iosipescu and short beam shear properties in carbon fiber polymer matrix composites. Mater. Res. 2010, 13, 63–69. https://doi.org/10.1590/s1516-14392010000100014.Search in Google Scholar
6. Dashtizadeh, Z., Ali, A., Abdan, K., Behmanesh, M. The use of infrared thermography in detecting the defects in kenaf-poly urethane composites. Polym. Plast. Technol. Eng. 2012, 51, 1155–1162. https://doi.org/10.1080/03602559.2012.671427.Search in Google Scholar
7. Park, B., An, Y. K., Sohn, H. Visualization of hidden delamination and debonding in composites through noncontact laser ultrasonic scanning. Compos. Sci. Technol. 2014, 100, 10–18. https://doi.org/10.1016/j.compscitech.2014.05.029.Search in Google Scholar
8. Yang, P., Elhajjar, R. Porosity content evaluation in carbon-fiber/epoxy composites using X-ray computed tomography. Polym. Plast. Technol. Eng. 2014, 53, 217–222. https://doi.org/10.1080/03602559.2013.843700.Search in Google Scholar
9. Lee, Y. J., Hong, S. C., Lee, J. R., Hong, S. J. Corner inspection method for L-shaped composite structures using laser ultrasonic rotational scanning technique. Adv. Compos. Mater. 2020, published ahead of print; https://doi.org/10.1080/09243046.2020.1825154.Search in Google Scholar
10. Huang, C. K. Study on co-cured composite panels with blade-shaped stiffeners. Compos. Appl. Sci. Manuf. 2003, 34, 403–410. https://doi.org/10.1016/s1359-835x(03)00081-2.Search in Google Scholar
11. Wang, X. M., Xie, F. Y., Li, M., Zhang, Z. G. Influence of tool assembly schemes and integral molding technologies on compaction of T-stiffened skins in autoclave process. J. Reinforc. Plast. Compos. 2010, 29, 1311–1322. https://doi.org/10.1177/0731684409102765.Search in Google Scholar
12. Wang, H. L., Xiong, M. R., Duan, Y. X., Yang, J., Yan, D. X., Xu, S. C. The hand making of radius fillers and the establishment of its evaluative requirements. Adv. Mater. Res. 2014, 936, 1973–1984. https://doi.org/10.4028/www.scientific.net/amr.936.1973.Search in Google Scholar
13. Zou, J., Zhan, L. H., Zhang, Y. A., Zhang, Y. A., Zeng, L. R. Influence of radius filler filling amount on quality of T-shaped stiffeners. Fiber. Reinf. Plast. Compos. 2017, 3, 70–75.Search in Google Scholar
14. Li, S. J., Zhan, L. H., Chang, T. F. Numerical simulation and experimental studies of mandrel effect on flow-compaction behavior of CFRP hat-shaped structure during curing process. Arch. Civ. Mech. Eng. 2018, 18, 1386–1400. https://doi.org/10.1016/j.acme.2018.04.008.Search in Google Scholar
15. Chen, S. J. Composite technology and large aircraft. Acta Pharmacol. Sin. 2008, 29, 605–610.Search in Google Scholar
16. Lin, Z. J., Zhan, L. H., Li, Y. B., Chang, T. F., Deng, F., Jiang, C. B., Liu, G. M., Kang, X. H. Experimental study on forming quality of hat-shaped component based on combined mandrel pressurization method. Mater. Sci. Forum 2019, 953, 80–87. https://doi.org/10.4028/www.scientific.net/msf.953.80.Search in Google Scholar
17. Li, J., Yao, X. F., Liu, Y. H., Cen, Z. Z., Kou, Z. J., Hu, X. C., Dai, D. Thermo-viscoelastic analysis of the integrated T-shaped composite structures. Compos. Sci. Technol. 2010, 70, 1497–1503. https://doi.org/10.1016/j.compscitech.2010.05.005.Search in Google Scholar
18. Russell, J. D., Madhukar, M. S., Genidy, M. S., Lee, A. Y. A new method to reduce cure-induced stresses in thermoset polymer composites, part III: correlating stress history to viscosity, degree of cure, and cure shrinkage. J. Compos. Mater. 2000, 34, 1926–1947. https://doi.org/10.1106/uy9u-f2qw-2fkk-91kg.Search in Google Scholar
19. Genidy, M. S., Madhukar, M. S., Russell, J. D. A new method to reduce cure-induced stresses in thermoset polymer composites, part II: closed loop feedback control system. J. Compos. Mater. 2000, 34, 1905–1925. https://doi.org/10.1106/3m0y-44xm-6wp8-wt7j.Search in Google Scholar
20. Zhang, D. L., Xue, X. C., Liang, X. Z., Zhan, L. H., Yang, X. B., Zheng, X. L. Experimental analysis of the causes of skin wrinkles below the radius filler of hat-stiffened skins. Acta Mater. Compos. Sin. 2020, 12, 1–8.Search in Google Scholar
21. Madhukar, M. S., Genidy, M. S. A new method to reduce cure-induced stresses in thermoset polymer composites, part I: test method. J. Compos. Mater. 2000, 34, 1905–1925. https://doi.org/10.1106/hucy-dy2b-2n42-ujbx.Search in Google Scholar
22. Meeks, C., Greenhalgh, E., Falzon, B. G. Stiffener debonding mechanisms in post-buckled CFRP aerospace panels. Compos. Appl. Sci. Manuf. 2005, 36, 934–946. https://doi.org/10.1016/j.compositesa.2004.12.003.Search in Google Scholar
© 2021 Walter de Gruyter GmbH, Berlin/Boston
