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A Methodology for Enhancing the Shear Response of Sandwich Composite Panel: Sandwich Composite Panel with Stair Keys


  • Department of Aerospace, Hindustan University, Chennai - 603103, Tamil Nadu, India


Objectives: In composite sandwich panel, delamination between the foam core and face sheet is due to inability to withstand shear load. Hence a methodology of introducing shear keys for enhancing the shear response to resist delamination is analysed in the present study. Methods/Statistical Analysis: The conventional sandwich panel under analysis is composed of Glass Fibre Reinforced Polymer (GFRP) skin with PVC (Polyvinyl chloride) foam core impregnated with epoxy resin. The present study is to introduce stair keys in between GFRP and PVC which are made by overlapping GFRP face sheets, with the length and depth to get the required step size. Parametric Finite Element (FE) investigation using ANSYS software has been performed to evaluate the foam core performance by grooving the foam material as stepped shapes. The effect of different length of the stepped grooves in foam material are analysed and its results are compared with conventional sandwich panel. The stair key response for number of steps ranging from n = 1, 3, 5 and 7 are investigated. Findings: The FE results showed an improvement in the shear stress response of the sandwich panel with stair grooved foam core with stair keys compared to conventional model. Also the stair inserts between the GFRP skin and the foam core increases the initial shear stiffness and ultimate shear strength of the proposed model of the sandwich panel. Application/Improvements: The present methodology acts as a new model of peel stopper mechanism, where the shear failure due to debonding of face sheet and foam core is rerouted to foam core. Also it is free from initial damage as there is no loss of solidarity of the bulk material at the foam core, cost effective and easy to design and manufacture compared to other pinning and stitching process.


Delamination, FEM Analysis, Sandwich Composite, Shear Response, Stair Keys, PVC Foam.

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  • Mitra N. A methodology for improving shear performance of marine grade sandwich composites: sandwich composite panel with shear key. Composite Structures.2010; 92(5):1065–72.
  • Kim JH, Lee YS, Park BJ, Kim DH. Evaluation of durability and strength of stitched foam-cored sandwich structures. Composite Structures. 1999,47(1–4):543–50.
  • Chang P, Mouritz AP, Cox BN. Properties and failure mechanisms of z-pinned laminates in monotonic and cyclic tension. Composite Part A. 2006, 37(10):1501–13.
  • Jakobsen J, Thomsen OT, Andreasen JH, Bozhevolnaya E. Crack deflection analyses of different peel stopper designs for sandwich structures. Composites Science and Technology.2009; 69(2):870–5.
  • George G , Deshpande T , Vikram S , Sharp S , Wadley K , Haydn NG. Hybrid core carbon fiber composite sandwich panels: Fabrication and mechanical response. Composites Science and Technology. 2013, 108:696–710.
  • Asha K , Varughese B , Saji D.Stress Analysis of a SteppedLap Bonded Repair Joint in Composite Laminate under Compressive Loading. ISAMPE National Conference on Composites INCCOM-12; 2012. p.1–8.
  • Mostafa A, Shankar K, Morozov EV. Effect of shear keys diameter on the shearperformance of composite sandwich panel with PVC and PU foam core: FEstudy. Composite Structures. 2013; 102:90–100.
  • Mitra N, Raja BR. Improving delamination resistance capacity of sandwichcomposite columns with initial face/ core debond. Composites Part B.2012; 43(3):1604–12.
  • Mukherjee A, Varughese B. Design guidelines for ply dropoff in laminated composite structures.Composites Part B Engineering. 2001; 32(2):153-64.
  • Mostafa A, Shankar K, Morozov EV. Insight into the shear behaviour ofcomposite sandwich panels with foam core. Materials Design. 2013; 50:92–101
  • Dransfield K, Baillie C, Mai Y-W. Improving the delamination resistance ofComposites Science and Technology. 1994; 50(3):305–17.
  • Mouritz AP, Leong KH, Herszberg I. A review of the effect of stitching on the in-plane mechanical properties of fibrereinforced polymer composites.Composites Part A. 1997; 28(12):979–91.
  • Grenestedt JL. Development of a new peel-stopper for sandwich structures.Composites Science and Technology. 2001; 61(11):1555–9.
  • Mouritz AP. Compression properties of z-pinned composite laminates. Composites Science and Technology. 2007; 67(15–16):3110–20.
  • Brien OTK, Krueger R. Influence of compression and shear on the strength ofcomposite laminates with z-pinned reinforcement. Applied Composite Materials.2006; 13(3):173–89.
  • Mouritz AP, Cox BN. A mechanistic approach to the properties of stitchedlaminates. Composites Part A. 2000; 31(1):1–27.
  • Jakobsen J, Bozhevolnaya E, Thomsen OT. New peel stopper concept forsandwich structures. Composites Science and Technology.2007; 67(15–16):3378–85.
  • Jakobsen J, Thomsen OT, Andreasen JH, Bozhevolnaya E. Crack deflection analyses of different peel stopper designs for sandwich structures. Composites Science and Technology. 2009; 69(6):870–5.
  • Loganathan TG, Murthy RK, Chandrasekharan K. Investigation on flexural response of GFRP composite laminate subjected to low velocity cyclic loading. Indian Journal of Science and Technology. 2015; 8(15):1–9. DOI: 10.17485/ijst/2015/v8i15/59383.
  • Gue-Wan H, Jae-Ung C. An analytical study on mechanical behavior of crack propagation in CFRP mode 2 adhesive specimens through simulation analysis. Indian Journal of Science and Technology. 2016; 9(24):1–7. DOI: 10.17485/ ijst/2016/v9i24/96014.


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