Fracture Toughness and Shear Strength of the Bonded Interface Between an Aluminium Alloy Skin and a FRP Patch

  • Prashant Kumar
  • Prakash Sonyabapu ShindeEmail author
  • Gaurav Bhoyar
Original Contribution


The existing techniques to determine the fracture properties such as critical energy release rate in mode I (GIc) and mode II (GIIc) of an interface between two sheets of same material were modified to determine these properties between the sheets of dissimilar materials and thickness. In addition, the interface shear strength (ISS) was also determined. Experiments were carried out on the specimens made of a pre-cracked thin aluminium alloy skin and a Fiber reinforced polymer (FRP) patch. Two kinds of surface preparation of the aluminium skin were employed; (i) emery-paper roughened surface (ERS) and (ii) Sodium Hydroxide (NaOH) treated surface (NTS). GIc of ERS specimen was found to be 36.1 J/m2, while it was found to be much higher for NTS specimens, that is, 87.3 J/m2. GIIc was found to be 282.4 J/m2 for ERS specimens and much higher as 734.5 J/m2 for NTS specimens. ISS was determined as 32.6 MPa for ERS specimen and significantly higher for NTS specimen, that is, 44.5 MPa. The micrographs obtained from a field emission-scanning electron microscope (FE-SEM) and the surface roughness test showed that the NTS was significantly rougher than the ERS, explaining the higher values of all the three kinds of NTS specimens.


Critical energy release rate Mode I Mode II Interfacial shear strength Bonded interface 


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Copyright information

© The Institution of Engineers (India) 2018

Authors and Affiliations

  • Prashant Kumar
    • 1
  • Prakash Sonyabapu Shinde
    • 1
    Email author
  • Gaurav Bhoyar
    • 1
  1. 1.Department of Mechanical EngineeringCollege of Engineering PunePuneIndia

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