Open Access Open Access  Restricted Access Subscription Access

Mode-I Fatigue Crack Healing in CFRP Composites Using Thermoplastic Healant



Mode-I fatigue crack healing in carbon fiber-reinforced polymer (CFRP) composites subjected to fatigue loading is investigated in this study. Laminated composites are highly susceptible to delamination, and delamination due to fatigue loading is one of the most critical damage modes in composite structures that may lead to a catastrophic failure. Hence, it is paramount to investigate and quantify the delamination crack growth behavior due to fatigue loading and explore methods to heal the delamination. Therefore, double cantilever beam (DCB) specimens of a carbon fiber-reinforced thermoset polymer (CFRP) composite containing thermoplastic healants were manufactured. Mode- I fatigue delamination experiments were carried out for virgin (initial case) and up to seven repeated healing cycles. The main objective of using thermoplastic healants, i.e., polycaprolactone (PCL) and shape memory polymer (SMP), was to close and then heal the cracks formed during fatigue loading and retain the fatigue life of the DCB specimen. The in-situ healing was achieved by activating macro fiber composite (MFC) actuators bonded to the DCB specimen, where the high frequency vibration of the actuator provides the heat necessary to close the cracks using thermoplastic healants. The insitu healing was triggered using MFCs after 5000 cycles of initial loading to allow initial crack extension. The DCB specimen was then loaded up to half a million cycles to study the effect of healing on fatigue life. From the experimental data of the virgin and healed specimens, the Paris law parameters were extracted, and the results obtained were repeatable. Significant increase in maximum Mode-I strain energy release rate (G ) observed after in-situ healing is likely due to the increase in the bond stiffness of the DCB specimen material of the healed zone. More research is needed to investigate the exact mechanism for the increase of G . Mode-I fatigue life improvement of up to a factor of 2 was observed after in-situ healing for the same delamination crack growth with respect to the virgin cycle prior to healing. We envision that these findings will be helpful in extending the service life of composites and result in significant repair cost savings.


Full Text:



Williams, K. A., D. R. Dreyer, and C. W. Bielawski. 2011. “The Underlying Chemistry of Self-Healing

Materials,” MRS Bulletin, 33(8):759–765.

White, S. R., N. R. Sottos, P. H. Geubelle, J. S. Moore, M. R. Kessler, S. R. Sriram, E. N. Brown, and S.

Viswanathan. 2001. “Autonomic Healing of Polymer Composites,” Nature, 409:794- 797.

Trask, R. S., and I. P. Bond. 2006. “Biomimetic Self-Healing of Advanced Composite Structures using Hollow

Glass Fibres,” Smart Materials and Structures, 15(3):704-710.

Li, G. and P. Zhang. 2013. “A Self-Healing Particulate Composite Reinforced with Strain Hardened Short

Shape Memory Polymer Fibers,” Polymer, 54(18):5075–5086.

Pingkarawat, K., T. Bhat, D. A. Craze, C. H. Wang, R. J. Varley, and A. P. Mouritz. 2013. “Healing of

Carbon Fibre-Epoxy Composites Using Thermoplastic Additives,” Polymer Chemistry, 4(18):5007–5015.

Wu, D. Y., S. Meure, and D. Solomon. 2008. “Self-Healing Polymeric Materials: A Review of Recent

Developments,” Progress in Polymer Science, 33:479–522.

Hayes, S. A., F. R. Jones, K. Marshiya, and W. Zhang. 2007. “A Self-Healing Thermosetting Composite

Material,” Composites Part A: Applied Science and Manufacturing, 38:1116–1120.

Nji, J., and G. Li. 2012. “Damage Healing Ability of a Shape Memory Polymer based Particulate Composite

with Small Thermoplastic Contents,” Smart Materials and Structures, 21(2):025011.

Nji, J., and G. Li. 2010. “A Biomimic Shape Memory Polymer based Self-Healing Particulate Composite,”

Polymer, 51:6021-6029.

Chen, X., M. A. Dam, K. Ono, A. Mal, H. Shen, S. R. Nutt, K. Sheran, and F. Wudl. 2002. “A Thermally remendable

cross-linked polymeric material,” Science, 295(5560):1698-1702.

Reifsnider, K. L., and A. Talug. 1980. “Analysis of Fatigue Damage in Composite Laminates,” International

Journal of Fatigue, 2(1):3-11.

Stelzer, S., A. J. Brunner, A. Arguelles, N. Murphy, G. M. Cano, and G. Pintec. 2014. “Mode I Delamination

Fatigue Crack Growth in Unidirectional Fiber Reinforced Composites: Results from ESIS TC4 Round-

Robins,” Engineering Fracture Mechanics, 116:92-107.

Tumino, D., and B. Zuccarello. 2011. “Fatigue Delamination Experiments on GFRP and CFRP Specimens

under Single and Mixed Fracture Modes,” Procedia Engineering, 10:1791-1796.

Ramirez, F. M. G., F. P. Garpelli, R. C. M. Sales, G. M. Candido, M. A. Arbelo, M. Y. Shiino, and M. V.

Donadon. 2018. “Experimental Characterization of Mode I Fatigue Delamination Growth Onset in Composite

Joints: A Comparative Study,” Materials and Design, 160:906-914.

Dahlen, C., and G. S. Springer. 1994. “Delamination Growth in Composites Under Cyclic Loads,” Journal of

Composite Materials, 28:732-781.

Vishe, N., B. Jony, M. Thapa, S. B. Mulani, and S. Roy, “Healing of Mode-I Fatigue Crack in Fiber-

Reinforced Composites using Thermoplastic Healants,” presented at the AIAA SciTech 2020 Forum, Orlando,

Florida, Jan 05-10, 2020.

Jony, B., M. Thapa, S. B. Mulani, and S. Roy. 2019. “Repeatable Self-Healing of Thermosetting Fiber Reinforced

Polymer Composites with Thermoplastic Healant,” Smart Materials and Structures, 28(2):025037.

Jony, B., M. Thapa, S. B. Mulani, and S. Roy. 2018. “Repeatability of Non-Autonomous Self-Healing with

Thermoplastic Healing Agent in Fiber Reinforced Thermoset Composite,” presented at the ASC 33rd Annual

Technical Conference, Seattle, Washington, September 24-26, 2018.

Thapa, M., B. Jony, S. B. Mulani, and S. Roy. 2018. “Intelligent Self-Healing Composite Structure Using

Predictive Self-Healing and Dynamic Data-Driven Application System,” in Handbook of Dynamic Data

Driven Applications Systems, Springer.

Thapa, M., B. Jony, S. B. Mulani, and S. Roy. 2019. “Experimental Characterization of Shape Memory Polymer

Enhanced Thermoplastic Self-Healing Carbon/Epoxy Composites,” AIAA SciTech 2019 Forum, San Diego,

California, Jan 07-11, 2019.

Brown, E. N., S. R. White, and N. R. Sottos. 2005. “Retardation and Repair of Fatigue Cracks in a Microcapsule

Toughened Epoxy Composite-Part II: In Situ Self-Healing,” Composites Science and Technology, 65(15):2474-

Hojo, M., S. Matsuda, M. Tanaka, S. Ochiai, and A. Murakami. 2006. “Mode I Delamination Fatigue

Properties of Interlayer-Toughened CF/Epoxy Laminates,” Composites Science and Technology, 66(5):665-

Nakai, Y., and C. Hiwa. 2002. “Effects of Loading Frequency and Environment on Delamination Fatigue

Crack Growth of CFRP,” International Journal of Fatigue, 24:161-170.

McMurray, M. K., and S. Amagi. 1999. “The Effect of Time and Temperature on Flexural Creep and Fatigue

Strength of a Silica Particle Filled Epoxy Resin,” Journal of Materials Science, 34:5927-5936.

Arguelles, A., J. Vina, A. F. Canteli, M. A. Castrillo, and J. Bonhomme. 2008. “Interlaminar Crack Initiation and

Growth Rate in a Carbon-Fibre Epoxy Composite Under Mode-I Fatigue Loading,” Composites Science and

Technology, 68:2325-2331.

Pingkarawat, K., C. H. Wang, R. J. Varley, and A. P. Mouritz. 2012. “Self-Healing of Delamination Fatigue

Cracks in Carbon Fibre–Epoxy Laminate Using Mendable Thermoplastic,” Journal of Materials Science,


Maiti, S., C. Shankar, P. H. Geubelle, and J. Kieffer. 2006. “Continuum and Molecular-Level Modeling of

Fatigue Crack Retardation in Self-Healing Polymers,” Journal of Engineering Materials and Technology,


Liu, T., E. Koranteng, Z. Wu, W. Xiao, and Q. Wu. 2017. “Structure and Properties of a Compatible Starch-pcl

Composite Using p-Phthaloyl Chloride-Based Prepolymer,” Journal of Applied Polymer Science, 134 (41):45400


Eshraghi, S., and S. Das. 2010. “Mechanical and Microstructural Properties of Polycaprolactone Scaffolds with

One-dimensional, Two-dimensional, and Three-dimensional Orthogonally Oriented Porous Architectures

Produced by Selective Laser Sintering,” Acta Biomaterialia, 6(7):2467–2476.

Properties of Shape Memory Polymer MM 5520 (Ether Type), SMP Technologies Inc., en/smp/

Tobushi, H., D. Shimada, S. Hayashi, and M. Endo. 2003. “Shape Fixity and Shape Recovery of Polyurethane

Shape-Memory Polymer Foams,” Proceedings of the Institution of Mechanical Engineers, Part L: Journal of

Materials: Design and Applications, 217:135–143.

ASTM. 2013. “Standard Test Method for Mode-I Interlaminar Fracture Toughness of Unidirectional Fiber-

Reinforced Polymer Matrix Composites,” ASTM D5528-13, ASTM International (ASTM).

ASTM. 2019. “Standard Test Method for Mode-I Fatigue Delamination Growth Onset of Unidirectional Fiber-

Reinforced Polymer Matrix Composites,” ASTM International.

Koenig, M., R. Krueger, K. Kussmaul, M. von Alberti, and M. Gaedke. 1997. “Characterizing Static and Fatigue

Interlaminar Fracture Behavior of a First Generation Graphite/Epoxy Composite,” The Composite Materials:

Testing and Design, ASTM, 13:60-81.


  • There are currently no refbacks.