Analysis of porosity and mechanical behavior of composite T-joints produced by random vibration-assisted vacuum processing


Voids are viewed as one of the most significant manufacture defects found within the composite T-joints and have been demonstrated to reduce their mechanical performance. In this work, the random vibration was introduced into the curing process with vacuum bag pressure to minimize the void content and improve the mechanical behavior of the composite T-joints. The range of accelerations was covered from 5 to 15 g, for different period of random vibrations. Identical static samples were produced by autoclave process with different pressures. The effects of application of random vibration on void content and mechanical performance were comprehensively assessed by combining the microscopy method and pull-off test. The results reveal that application of random vibration can improve the fluidity of matrix, impede the void growth, while, at the same time, develop the adhesion between fibers and matrix. For this reason, void content was reduced to less than 1%, and their morphological characteristics were similar to the pattern cured under high pressure. With the large observed decrease in void content, the ultimate pull-off load increases from 1006 N to higher than 3000 N compared to 0 MPa autoclave process. Meanwhile, significant successive cusps were formed along the crack propagation direction on the fracture surfaces due to the improvement of the fiber-matrix bonding caused by application of vibration, which indicated that the carrying capacity in direction perpendicular to fibers was improved. Therefore, application of random vibration could reduce the dependence of final forming qualities on high curing pressure.

This is a preview of subscription content, log in to check access.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 8
Fig. 9
Fig. 10


  1. 1.

    Wang H, Hu Y, Cong W, Burks AR (2019) Rotary ultrasonic machining of carbon fiber–reinforced plastic composites: effects of ultrasonic frequency. Int J Adv Manuf Technol 104:3759–3772

    Article  Google Scholar 

  2. 2.

    Chen F, Zhan LH, Xu YQ (2015) Simulation of mold temperature distribution in a running process autoclave. Iran Polym J 24:927–934

    Article  Google Scholar 

  3. 3.

    Prasad N, Agrawal VK, Sinha S (2016) Banana fiber reinforced low-density polyethylene composites: effect of chemical treatment and compatibilizer addition. Iran Polym J 25:229–241

    CAS  Article  Google Scholar 

  4. 4.

    Chen F, Zhan LH, Li SJ (2016) Refined simulation of temperature distribution in molds during autoclave process. Iran Polym J 25:775–785

    Article  Google Scholar 

  5. 5.

    Ata MH, Abu-Okail M, Essa GMF, Mahmoud TS, Hassab-Allah I (2019) Failure mode and failure load of adhesively bonded composite joints made by glass fiber-reinforced polymer. J Fail Anal Prev 19:950–957

    Article  Google Scholar 

  6. 6.

    Pirouzfar V, Mosalmani M, Mortezaei M (2015) Experimental study, modeling and optimization to improve heat resistance of modified resole-pitch composites. Iran Polym J 24:829–836

    CAS  Article  Google Scholar 

  7. 7.

    Haddad RH, Marji CS (2019) Composite strips with U-shaped CFRP wrap anchor systems for strengthening reinforced concrete beams. Int J Civ Eng 17:1799–1811

    Article  Google Scholar 

  8. 8.

    Mangalgiri PD (1999) Composite materials for aerospace applications. Bull Mater Sci 22:657–664

    CAS  Article  Google Scholar 

  9. 9.

    Saito H, Kikuchi R, Kimpar I (2020) Evaluation of mode I interlaminar fracture toughness in asymmetric interlayer in CFRP laminates. Adv Compos Mater 29:163–177

    CAS  Article  Google Scholar 

  10. 10.

    Abdus S, Cheng X, Huang W, Ahmed A, Hu R (2019) Bearing failure and influence factors analysis of metal-to-composite bolted joints at high temperature. J Braz Soc Mech Sci Eng 41:298–309

    Article  Google Scholar 

  11. 11.

    Guermazi N, Ben Tarjem A, Ksouri I, Ayedi HF (2016) On the durability of FRP composites for aircraft structures in hygrothermal conditioning. Compos Part B Eng 85:294–304

    CAS  Article  Google Scholar 

  12. 12.

    Chung DDL (2017) Processing-structure–property relationships of continuous carbon fiber polymer-matrix composites. Mat Sci Eng R 113:1–29

    Article  Google Scholar 

  13. 13.

    Bai JB, Shenoi RA, Yun XY, Xiong JJ (2017) Progressive damage modelling of hybrid RTM-made composite Π-joint under four-point flexure using mixed failure criteria. Compos Struct 159:327–334

    Article  Google Scholar 

  14. 14.

    Li S, Zhan L, Chang T (2018) Numerical simulation and experimental studies of mandrel effect on flow-compaction behavior of CFRP hat-shaped structure during curing process. Arch Civ Mech Eng 18:1386–1400

    Article  Google Scholar 

  15. 15.

    Li S, Pu Y, Zhan L, Bai H, Zhou Y, Yin R (2015) Effect of mandrel structures on co-curing quality for polymer composite hat-stiffened structures. Fiber Polym 16:1898–1907

    CAS  Article  Google Scholar 

  16. 16.

    Liu L, Zhang B-M, Wang D-F, Wu Z-J (2006) Effects of cure cycles on void content and mechanical properties of composite laminates. Compos Struct 73:303–309

    Article  Google Scholar 

  17. 17.

    Agius SL, Fox BL (2015) Rapidly cured out-of-autoclave laminates: Understanding and controlling the effect of voids on laminate fracture toughness. Compos A Appl Sci Manuf 73:186–194

    CAS  Article  Google Scholar 

  18. 18.

    Agius SL, Magniez KJC, Fox BL (2010) Fracture behaviour of a rapidly cured polyethersulfone toughened carbon fibre/epoxy composite. Compos Struct 92:2119–2127

    Article  Google Scholar 

  19. 19.

    Agius SL, Magniez KJC, Fox BL (2013) Cure behaviour and void development within rapidly cured out-of-autoclave composites. Compos Part B Eng 47:230–237

    CAS  Article  Google Scholar 

  20. 20.

    Zhu H, Wu B, Li D, Zhang D, Chen Y (2011) Influence of voids on the tensile performance of carbon/epoxy fabric laminates. J Mater Sci Technol 27:69–73

    CAS  Article  Google Scholar 

  21. 21.

    Wang X, Xie F, Li M, Zhang Z (2009) Influence of tool assembly schemes and integral molding technologies on compaction of t-stiffened skins in autoclave process. J Reinf Plast Compos 29:1311–1322

    CAS  Article  Google Scholar 

  22. 22.

    Burns L, Mouritz AP, Pook D, Feih S (2016) Strengthening of composite T-joints using novel ply design approaches. Compos Part B Eng 88:73–84

    Article  Google Scholar 

  23. 23.

    Bigaud J, Aboura Z, Martins AT, Verger S (2018) Analysis of the mechanical behavior of composite T-joints reinforced by one side stitching. Compos Struct 184:249–255

    Article  Google Scholar 

  24. 24.

    Koh TM, Feih S, Mouritz AP (2012) Strengthening mechanics of thin and thick composite T-joints reinforced with z-pins. Compos A Appl Sci Manuf 43:1308–1317

    CAS  Article  Google Scholar 

  25. 25.

    Ghiorse SR, Jurta RM (1991) Effects of low frequency vibration processing on carbon/epoxy laminates. Composites 22:3–8

    CAS  Article  Google Scholar 

  26. 26.

    Muric-Nesic J, Compston P, Stachurski ZH (2011) On the void reduction mechanisms in vibration assisted consolidation of fibre reinforced polymer composites. Compos A Appl Sci Manuf 42:320–327

    Article  CAS  Google Scholar 

  27. 27.

    Muric-Nesic J, Compston P, Noble N, Stachurski ZH (2009) Effect of low frequency vibrations on void content in composite materials. Compos A Appl Sci Manuf 40:548–551

    Article  CAS  Google Scholar 

  28. 28.

    Meier R, Kahraman I, Seyhan AT, Zaremba S, Drechsler K (2016) Evaluating vibration assisted vacuum infusion processing of hexagonal boron nitride sheet modified carbon fabric/epoxy composites in terms of interlaminar shear strength and void content. Compos Sci Technol 128:94–103

    CAS  Article  Google Scholar 

  29. 29.

    Kitselis A, Traiforos NA, Manolakos DE (2016) The effect of resonance on the void content in CFRP tubes. Compos B Eng 106:164–171

    CAS  Article  Google Scholar 

  30. 30.

    Trask RS, Hallett SR, Helenon FMM, Wisnom MR (2012) Influence of process induced defects on the failure of composite T-joint specimens. Compos A Appl Sci Manuf 43:748–757

    Article  Google Scholar 

  31. 31.

    Wu H, Xiao J, Xing S, Wen S, Yang F, Yang J (2015) Numerical and experimental investigation into failure of T700/bismaleimide composite T-joints under tensile loading. Compos Struct 130:63–74

    Article  Google Scholar 

  32. 32.

    Wang K, Tao JY, Chen X (2007) Analysis of exciting signals and their affecting factors of repetitive shock machines. J Vibr Eng 20:249–254.

    Article  Google Scholar 

  33. 33.

    Jiang P, Hou JJ (2010) Characteristics and principle of the new cyclostationary and non-Gaussian omni-axis vibration environment. In: 2010 2nd International Asia Conference on Informatics in Control, Automation and Robotics (CAR 2010), Wuhan, China, March, pp 117–121.

  34. 34.

    Charki A, Laronde R, Guérin F, Bigaud D, Coadou F (2011) Robustness evaluation using highly accelerated life testing. Int J Adv Manuf Technol 56:1253–1261

    Article  Google Scholar 

  35. 35.

    Chen Y-S, Chuong L-H (2014) Efficiency improvement of the highly accelerated life testing system by using multiple hammers. J Mech Sci Technol 28:4815–4831

    Article  Google Scholar 

  36. 36.

    Hernández S, Sket F, González C, Lorca JL (2013) Optimization of curing cycle in carbon fiber-reinforced laminates: void distribution and mechanical properties. Compos Sci Technol 85:73–82

    Article  CAS  Google Scholar 

  37. 37.

    Tan W, Naya F, Yang L, Chang T, Falzon BG, Zhan L, Molina-Aldareguía JM, González C, Llorca J (2018) The role of interfacial properties on the intralaminar and interlaminar damage behaviour of unidirectional composite laminates: experimental characterization and multiscale modelling. Compos B Eng 138:206–221

    CAS  Article  Google Scholar 

  38. 38.

    Chang TF, Zhan LH, Tan W, Li SJ (2017) Effect of autoclave pressure on interfacial properties at micro- and macro-level in polymer-matrix composite laminates. Fibers Polym 18:1614–1622

    CAS  Article  Google Scholar 

  39. 39.

    Little JE, Yuan X, Jones MI (2012) Characterisation of voids in fibre reinforced composite materials. NDT E Int 46:122–127

    CAS  Article  Google Scholar 

  40. 40.

    Huang CK (2003) Study on co-cured composite panels with blade-shaped stiffeners. Compos A Appl Sci Manuf 34:403–410

    Article  Google Scholar 

  41. 41.

    Burns L, Mouritz AP, Pook D, Feih S (2015) Bio-inspired hierarchical design of composite T-joints with improved structural properties. Compos B Eng 69:222–231

    CAS  Article  Google Scholar 

  42. 42.

    Loos AC, Springer GS (1983) Curing of epoxy matrix composites. J Compos Mater 17:135–169

    CAS  Article  Google Scholar 

  43. 43.

    Kardos JL, Dudukovic MP, Dave R (1986) Void growth and resin transport during processing of thermosetting-matrix composites. In: Dušek K (ed) Epoxy resins and composites IV. Advances in polymer science, vol 80. Springer, Berlin

    Google Scholar 

  44. 44.

    Lauterborn W, Kurz T, Mettin R, Ohl CD (1999) Experimental and theoretical bubble dynamics. In: Prigogine I, Rice SA (eds) Advances in chemical physics, vol 110. Wiley, New York, pp 295–380

    Google Scholar 

  45. 45.

    Zhang Y, Li S (2014) Mass transfer during radial oscillations of gas bubbles in viscoelastic mediums under acoustic excitation. Int J Heat Mass Transf 69:106–116

    Article  Google Scholar 

  46. 46.

    Park Y-B, Lee B-H, Kweon J-H, Choi J, Choi I-H (2012) The strength of composite bonded T-joints transversely reinforced by carbon pins. Compos Struct 94:625–634

    Article  Google Scholar 

  47. 47.

    Guo S, Morishima R (2011) Numerical analysis and experiment of composite sandwich T-joints subjected to pulling load. Compos Struct 94:229–238

    Article  Google Scholar 

  48. 48.

    Heimbs S, Nogueira AC, Hombergsmeier E, May M, Wolfrum J (2014) Failure behaviour of composite T-joints with novel metallic arrow-pin reinforcement. Compos Struct 110:16–28

    Article  Google Scholar 

  49. 49.

    Kim CH, Jo DH, Choi JH (2017) Failure strength of composite T-joints prepared using a new 1-thread stitching process. Compos Struct 178:225–231

    Article  Google Scholar 

  50. 50.

    Justo J, Reinoso J, Blázquez A (2017) Experimental failure investigation of pull-off tests of single T-stiffened composite specimens. Compos Struct 177:13–27

    Article  Google Scholar 

Download references


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. 51675538. The authors would like to gratefully acknowledge the composite research team members of Central South University for their support and useful discussions in this research.

Author information



Corresponding authors

Correspondence to Lihua Zhan or Xing Zhao.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Yang, X., Zhan, L., Zhao, X. et al. Analysis of porosity and mechanical behavior of composite T-joints produced by random vibration-assisted vacuum processing. Iran Polym J (2020).

Download citation


  • Composite T-joints
  • Random vibration-assisted vacuum processing
  • Autoclave process
  • Void content
  • Pull-off test