Journal of Failure Analysis and Prevention

, Volume 19, Issue 1, pp 182–192 | Cite as

Enhanced Failure Load Bearing in Adhesively Bonded Strap Repairs: Numerical Analysis and Experimental Results

  • Mohammad Ali Saeimi SadighEmail author
Technical Article---Peer-Reviewed


Adhesively bonded repairs are frequently used to repair aluminum structures due to their attractive options compared to traditional methods such as welding or riveting. A new method of increasing the repair’s strength against uniaxial tensile loads is used in this study. For this purpose, standard single-strap (SS) and double-strap (DS) repairs were produced with aluminum patch. In the first step, an epoxy-based adhesive was employed to create SS and DS repairs using neat adhesive and 0.5 wt.% reduced graphene oxide (RGO)-reinforced adhesive. Afterward, samples of SS and DS joints with the reinforced adhesive were manufactured to study the effect of the added RGO. Uniaxial tensile tests were conducted and above 30% enhancement in the ultimate load was observed in the joints bonded with reinforced adhesive. The repaired joints were analyzed by finite element (FE) method using cohesive zone modeling technique to obtain failure loads. For this purpose, two sets of tests (a) double cantilever beam and (b) end notch flexure tests were implemented to estimate the cohesive zone model CZM parameters. Comparing the results obtained from experiments and the numerical simulations shows that FE models accurately predict the failure load in the reinforced and unreinforced repaired joints.


Patch repair Adhesive Cohesive zone model RGO 

List of symbols


Specimen width


Diagonal matrix


Identity matrix


Energies released (mode II)


Energies released (mode I)


Applied load


Maximum normal nominal stress


Maximum shear nominal stress


Vector of relative displacement


Current damage relative displacement in mode I


Onset damage relative displacement in mode II


Poisson’s ratio


  1. 1.
    E. Marques, L.F. da Silva, Joint strength optimization of adhesively bonded patches. J. Adhes. 84(11), 915–934 (2008)CrossRefGoogle Scholar
  2. 2.
    B.B. Bouiadjra, H. Fekirini, M. Belhouari, B. Boutabout, B. Serier, Fracture energy for repaired cracks with bonded composite patch having two adhesive bands in aircraft structures. Comput. Mater. Sci. 40(1), 20–26 (2007)CrossRefGoogle Scholar
  3. 3.
    A. Pinto, R. Campilho, I.R. Mendes, A. Baptista, Strap repairs using embedded patches: numerical analysis and experimental results. J. Adhes. Sci. Technol. 28(14–15), 1530–1544 (2014)CrossRefGoogle Scholar
  4. 4.
    Ş. Çitil, Ş. Temiz, H. Altun, A. Özel, Determination of mechanical properties of double-strap adhesive joints with an embedded patch. J. Adhes. Sci. Technol. 25(18), 2555–2567 (2011)CrossRefGoogle Scholar
  5. 5.
    Ş. Temiz, Application of bi-adhesive in double-strap joints subjected to bending moment. J. Adhes. Sci. Technol. 20(14), 1547–1560 (2006)CrossRefGoogle Scholar
  6. 6.
    A. Pinto, R. Campilho, I. Mendes, A. Baptista, Strap repairs using embedded patches: numerical analysis and experimental results. J. Adhes. Sci. Technol. 28(14–15), 1530–1544 (2014)CrossRefGoogle Scholar
  7. 7.
    S. Iijima, Helical microtubules of graphitic carbon. Nature 6348(48), 56–58 (1991)CrossRefGoogle Scholar
  8. 8.
    E. Flahaut, A. Peigney, C. Laurent, C. Marliere, F. Chastel, A. Rousset, Carbon nanotube-metal-oxide nanocomposites: microstructure, electrical conductivity and mechanical properties. Acta Mater. 48(14), 3803–3812 (2000)CrossRefGoogle Scholar
  9. 9.
    Y. Geng, M.Y. Liu, J. Li, X.M. Shi, J.K. Kim, Effects of surfactant treatment on mechanical and electrical properties of CNT/epoxy nanocomposites. Compos. Part A Appl. Sci. Manuf. 39(12), 1876–1883 (2008)CrossRefGoogle Scholar
  10. 10.
    P.C. Ma, J.-K. Kim, B.Z. Tang, Functionalization of carbon nanotubes using a silane coupling agent. Carbon 44(15), 3232–3238 (2006)CrossRefGoogle Scholar
  11. 11.
    J. Zhu, J. Kim, H. Peng, J.L. Margrave, V.N. Khabashesku, E.V. Barrera, Improving the dispersion and integration of single-walled carbon nanotubes in epoxy composites through functionalization. Nano Lett. 3(8), 1107–1113 (2003)CrossRefGoogle Scholar
  12. 12.
    P. Karapappas, A. Vavouliotis, P. Tsotra, V. Kostopoulos, A. Paipetis, Enhanced fracture properties of carbon reinforced composites by the addition of multi-wall carbon nanotubes. J. Compos. Mater. 43(9), 977–985 (2009)CrossRefGoogle Scholar
  13. 13.
    K.D.S. Davey, Development of Carbon Nanotube/Carbon Fiber Multiscale Reinforcement Composites, Electronic Theses, Treatises and Dissertations Paper 823 (2005)Google Scholar
  14. 14.
    F.H. Gojny, M.H. Wichmann, B. Fiedler, K. Schulte, Influence of different carbon nanotubes on the mechanical properties of epoxy matrix composites—a comparative study. Compos. Sci. Technol. 65(15), 2300–2313 (2005)CrossRefGoogle Scholar
  15. 15.
    S. Jana, W.-H. Zhong, Y.X. Gan, Characterization of the flexural behavior of a reactive graphitic nanofibers reinforced epoxy using a non-linear damage model. Mater. Sci. Eng. A 445, 106–112 (2007)CrossRefGoogle Scholar
  16. 16.
    Y.J. Kim, T.S. Shin, C.H. Do, J.H. Kwon, Y.-C. Chung, H.G. Yoon, Electrical conductivity of chemically modified multiwalled carbon nanotube/epoxy composites. Carbon 43(1), 23–30 (2005)CrossRefGoogle Scholar
  17. 17.
    M. Rahman, S. Zainuddin, M. Hosur, J. Malone, M. Salam, A. Kumar et al., Improvements in mechanical and thermo-mechanical properties of e-glass/epoxy composites using amino functionalized MWCNTs. Compos. Struct. 94(8), 2397–2406 (2012)CrossRefGoogle Scholar
  18. 18.
    M.-H. Kang, J.-H. Choi, J.-H. Kweon, Fatigue life evaluation and crack detection of the adhesive joint with carbon nanotubes. Compos. Struct. 108, 417–422 (2014)CrossRefGoogle Scholar
  19. 19.
    G. Gkikas, D. Sioulas, A. Lekatou, N. Barkoula, A. Paipetis, Enhanced bonded aircraft repair using nano-modified adhesives. Mater. Des. 41, 394–402 (2012)CrossRefGoogle Scholar
  20. 20.
    J. Kim, B.-S. Yim, J.-M. Kim, J. Kim, The effects of functionalized graphene nanosheets on the thermal and mechanical properties of epoxy composites for anisotropic conductive adhesives (ACAs). Microelectron. Reliab. 52(3), 595–602 (2012)CrossRefGoogle Scholar
  21. 21.
    U. Khan, P. May, H. Porwal, K. Nawaz, J.N. Coleman, Improved adhesive strength and toughness of polyvinyl acetate glue on addition of small quantities of graphene. ACS Appl. Mater. Interfaces 5(4), 1423–1428 (2013)CrossRefGoogle Scholar
  22. 22.
    S. Abdolhosseinzadeh, H. Asgharzadeh, H.S. Kim, Fast and fully-scalable synthesis of reduced graphene oxide. Sci. Rep. 5, 10160 (2015)CrossRefGoogle Scholar
  23. 23.
    M.A.S. Sadigh, G. Marami, Bearing and cleavage failure simulation of single lap bolted joint using finite element method. Trans. Indian Inst. Met. 69(8), 1613–1622 (2016)CrossRefGoogle Scholar
  24. 24.
    M.A.S. Sadigh, G. Marami, Investigating the effects of reduced graphene oxide additive on the tensile strength of adhesively bonded joints at different extension rates. Mater. Des. 92, 36–43 (2016)CrossRefGoogle Scholar
  25. 25.
    R. Campilho, M.D. Banea, A. Pinto, L.F. da Silva, A. De Jesus, Strength prediction of single-and double-lap joints by standard and extended finite element modelling. Int. J. Adhes. Adhes. 31(5), 363–372 (2011)CrossRefGoogle Scholar
  26. 26.
    P. Hu, X. Han, W. Li, L. Li, Q. Shao, Research on the static strength performance of adhesive single lap joints subjected to extreme temperature environment for automotive industry. Int. J. Adhes. Adhes. 41, 119–126 (2013)CrossRefGoogle Scholar
  27. 27.
    L.F. da Silva, T. Rodrigues, M. Figueiredo, M. De Moura, J. Chousal, Effect of adhesive type and thickness on the lap shear strength. J. Adhes. 82(11), 1091–1115 (2006)CrossRefGoogle Scholar
  28. 28.
    M. De Moura, J. Gonçalves, J. Chousal, R. Campilho, Cohesive and continuum mixed-mode damage models applied to the simulation of the mechanical behaviour of bonded joints. Int. J. Adhes. Adhes. 28(8), 419–426 (2008)CrossRefGoogle Scholar
  29. 29.
    M. de Moura, J. Gonçalves, A. Magalhães, A straightforward method to obtain the cohesive laws of bonded joints under mode I loading. Int. J. Adhes. Adhes. 39, 54–59 (2012)CrossRefGoogle Scholar
  30. 30.
    G. Marami, S.A. Nazari, S.A. Faghidian, F. Vakili-Tahami, S. Etemadi, Improving the mechanical behavior of the adhesively bonded joints using RGO additive. Int. J. Adhes. Adhes. 70, 277–286 (2016)CrossRefGoogle Scholar

Copyright information

© ASM International 2019

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringAzarbaijan Shahid Madani UniversityTabrizIran

Personalised recommendations