Continuous Damage Monitoring of a Thin Composite Structural with Mismatched Stiffener in a Combined Joint Using Fiber Bragg Grating under Tension and Three-Point Loading


A joint combining riveting and bonding is considered in terms of structural performance if the composite structure has a mismatched stiffener. The transfer loading is correlated with high performance aerospace joints to increase delamination resistance in the out-of-plane direction. However, combined joints (rivet/bonded) will create a bearing area that induces another potential damage source aside from secondary bending moment on the edge of the stiffener. Another problem is that the structure is difficult to be inspected by using conventional methods because of limited accessibility. The use of embedded fiber Bragg grating (FBG) technology in the structure as a strain sensor can potentially solve the problem in structures that have a stiffness mismatch. The FBG can be used to detect and characterize delamination before it reaches a critical stage. The model used to represent this problem is a thin composite stiffened skin under two load cases: tension and three-point bending. Finite element modeling using a traction versus separation theory is performed to determine the critical area on the specimen for placement of the FBG before manufacturing and testing. Experiments were presented to determine the distribution of load in a combined joint under both loading cases using ideal loads to create a secondary bending moment and bearing loads in the stiffness-mismatched structure. In this research, the FBG successfully detected and characterized the delamination caused in both loading cases. In addition, FBG can predict the delamination growth quantitatively. A spectrum graph of the FBG results can be used to replace the conventional mechanical graph in composite structural health monitoring in real applications.

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A. Trilaksono, N. Watanabe, H. Hoshi, A. Kondo, Y. Iwahori and S. Takeda, "Continuous Damage Monitoring of a Thin Composite Structural with Mismatched Stiffener in a Combined Joint Using Fiber Bragg Grating under Tension and Three-Point Loading," Open Journal of Composite Materials, Vol. 3 No. 3, 2013, pp. 63-87. doi: 10.4236/ojcm.2013.33008.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] J. M. Gere and S. P. Timoshenko, “Mechanics of Materials,” 3rd SI Edition, Chapman & Hall, London, 1991.
[2] J. Schijve, “Secondary Bending Moment,” NLR 72036U, 1972.
[3] A. A. Baker, “Bonded Repair of Aircraft Structures,” Martinus Nijhoff Publishers, Leiden, 1988. doi:10.1007/978-94-009-2752-0
[4] S. Takeda, Y. Okabe, T. Yamamoto and N. Takeda, “Detection of Edge Delamination in CFRP Laminates under Cyclic Loading Using Small-Diameter FBG Sensors,” Composite Science and Technology Journal, Vol. 63, No. 13, 2003, pp. 1885-1894. doi:10.1016/S0266-3538(03)00159-3
[5] S. Huang, M. M. Ohn, M. Leblanc and R. M. Measures, “Continuous Arbitrary Strain Profile Measurements with Fiber Bragg Grating,” Smart Material and Structure, Vol. 7, No. 2, 1998, pp. 248-256. doi:10.1088/0964-1726/7/2/012
[6] S. Takeda, S. Minakuchi, Y. Okabe and N. Takeda, “Delamination Monitoring of Laminated Composites Subjected to Low-Velocity Impact Using Small-Diameter FBG Sensors,” Composites Part A: Applied Science and Manufacturing, Vol. 36, No. 7, 2005, pp. 903-908.
[7] K. Peters, P. Pattis, J. Botsis and P. Giaccari, “Experimental Verification of Response of Embedded Optical Fiber Bragg Grating Sensors in Non-Homogeneous Strain Fields,” Optics and Lasers in Engineering, Vol. 33, No. 2, 2000, pp. 107-119. doi:10.1016/S0143-8166(00)00033-6
[8] H. Wang, S. L. Ogin, A. M. Thorne and G. T. Reed, “Interaction between Optical Fibre Sensors and Matrix Cracks in Cross-Ply GFRP Laminates. Part 2: Crack Detection,” Composite Science and Technology, Vol. 66, No. 13, 2006, pp. 2367-2378. doi:10.1016/j.compscitech.2005.10.021
[9] N. Takeda, “Characterization of Microscopic Damage in Composite Laminates and Real-Time Monitoring by Embedded Optical Fiber Sensors,” International Journal of Fatigue, Vol. 24, No. 2-4, 2002, pp. 281-289. doi:10.1016/S0142-1123(01)00083-4
[10] S. Yashiro, N. Takeda, T. Okabe and H. Sekine, “A New Approach to Predicting Multiple Damage States in Composite Laminates with FBG Sensors,” Composite Science and Technology Journal, Vol. 65, No. 3-4, 2005, pp. 659-667. doi:10.1016/j.compscitech.2004.09.022
[11] J. Botsis, L. Humbert, F. Colpo and P. Giaccari, “Embedded Fiber Bragg Grating Sensor for Internal Strain Measurements in Polymeric Materials,” Optic and Lasers in Engineering, Vol. 43, No. 3-5, 2005, pp. 491-510. doi:10.1016/j.optlaseng.2004.04.009
[12] H. Y. Ling, K. T. Lau, L. Cheng and Z. Q. Su, “Mode II Fracture Behavior Monitoring for Composite Laminates using Embedded Fiber Bragg Grating Sensors,” Composite Structure, Vol. 76, No. 1-2, 2006, pp. 88-93. doi:10.1016/j.compstruct.2006.06.013
[13] P. P. Camanho, C. G. Davila and M. F. De Moura, “Numerical Simulation of Mixed-Mode Progressive Delamination Composite Materials,” Journal of Composite Materials, Vol. 37, No. 16, 2003, pp. 1415-1438. doi:10.1177/0021998303034505
[14] A. Turon, P. P. Camanho, J. Costa and C. G. Davila, “A Damage Model for the Simulation of Delamination in Advanced Composites under Variable-Mode Loading,” Mechanics of Materials, Vol. 38, No. 11, 2006, pp. 1072-1089. doi:10.1016/j.mechmat.2005.10.003
[15] Q. Yang and B. N. Cox, “Cohesive Models for Damage Evolution in Laminated Composites,” International Journal of Fracture, Vol. 133, No. 2, 2005, pp. 107-137. doi:10.1007/s10704-005-4729-6
[16] E. D. Reedy, F. J. Mello and T. R. Guess, “Modeling the Initiation and Growth of Delaminations in Composite Structures,” Journal of Composite Materials, Vol. 31, No. 8, 1997, pp. 812-831. doi:10.1177/002199839703100804
[17] J.-H. Kweon, J.-W. Jung, T.-H. Kim, J.-H. Choi and D.-H. Kim, “Failure of Carbon Composite-to-Aluminum Joints Combined Mechanical Fastening and Adhesive Bonding,” Composite Structures, Vol. 75, No. 1-4, 2006, pp. 192-198. doi:10.1016/j.compstruct.2006.04.013
[18] J. W. H. Yap, M. L. Scott, R. S. Thomson and D. Hachenberg, “The Analysis of Skin-to-Stiffener Debonding in Composite Aerospace Structures,” Composite Structures, Vol. 57, No. 1-4, 2002, pp. 425-435. doi:10.1016/S0263-8223(02)00110-1
[19] A. G. Magalhaes, M. F. S. F. de Moura and J. P. M. Goncalves, “Evaluation of Stress Concentration Effects Single-Lap Bonded Joint of Laminate Composite Materials,” Adhesion and Adhesive, Vol. 25, No. 4, 2005, pp. 313-319. doi:10.1016/j.ijadhadh.2004.10.002

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