Revised adjusted factor for delamination measurement in drilling of composites


  • Ritesh Bhat Department of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, India 576104
  • Nanjangud Mohan Department of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, India 576104
  • Sathyashankara Sharma Department of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, India 576104


composites, damage analysing models, delamination, drilling, fibres


Delamination, an inter-ply damage, is a major concern during the drilling of FRP composites.  It is evident from past studies that the focus of the researchers has been mostly on reducing the delamination damages by optimising the input parameters, cutting parameters, tool geometry parameters and work materials properties, rather than improving the model for quantifying the delamination factor to get near-to right values.  Though Davim’s adjusted model overcomes the demerits of mostly proposed models, it is believed to give the exaggerated values of the delamination factor.  Thus, the present study proposes a revised basic two-dimensional model to quantify the delamination factor for fibre-reinforced polymer composites, while addressing the exaggeration effect caused by the most commonly used adjusted delamination factor model.  The developed model in this work resulted from combining two prior stated models: Davim’s adjusted model and Da Silva's minimum delamination factor model.  The proposed model is validated experimentally and reconfirmed with additional experiments concerning its applicability and efficacy.  The delamination damage in this work is characterised by the peel up mechanism for the experimental validation purpose.  The results indicate that the exaggeration effect is reduced by 13 to 15% in determining delamination factor value using the proposed model, compared to the existing two-dimensional adjusted factor model.


Abrão, A. M., Rubio, J. C. C., Faria, P. E., & Davim, J. P. (2008). The effect of cutting tool geometry on thrust force and delamination when drilling glass fibre reinforced plastic composite. Materials and Design, 29(2), 508-513. DOI:

Bhat, R., Mohan, N., Kulkarni, S. M., & Sharma, S. (2019). Predictive analysis of peel up delamination in glass fibre reinforced polyester composite drilling. International Journal of Mechanical and Production Engineering Research and Development, 9(Special Issue 2), 694-702.

Bhat, R., Mohan, N., Sharma, S., Shandilya, M., & Jayachandran, K. (2019). An integrated approach of CCD-TOPSIS-RSM for optimising the marine grade GFRP drilling process parameters. Materials Today: Proceedings, 19, 307-311. DOI:

Chen, W. C. (1997). Some experimental investigations in the drilling of carbon fiber-reinforced plastic (CFRP) composite laminates. International Journal of Machine Tools and Manufacture, 37(8), 1097-1108. DOI:

Davim, J. P., Reis, P., & António, C. C. (2004). Experimental study of drilling glass fibre reinforced plastics (GFRP) manufactured by hand lay-up. Composites Science and Technology, 64(2), 289-297. DOI:

Davim, J. P., Rubio, J. C., & Abrao, A. M. (2007). A novel approach based on digital image analysis to evaluate the delamination factor after drilling composite laminates. Composites Science and Technology, 67(9), 1939-1945. DOI:

Ekici, E., Motorcu, A. R., & Uzun, G. (2021). Multi-Objective Optimisation of Process Parameters for Drilling Fiber-Metal Laminate Using a Hybrid GRAPCA Approach. FME Transactions, 49(2), 356-366. DOI:

Ficici, F., & Ayparcasi, Z. (2015). Effects of cutting parameters on delamination during drilling of Polyphthalamide (PPA) matrix composite material with 30% glass fibre reinforcement. Acta Physica Polonica A, 127(4), 1118-1120. DOI:

Ficici, F., Ayparcasi, Z., & Unal, H. (2017). Influence of cutting tool and conditions on machinability aspects of polyphthalamide (PPA) matrix composite materials with 30 % glass fibre reinforced. International Journal of Advanced Manufacturing Technology, 90(9-12), 3067-3073. DOI:

Gaitonde, V. N., Karnik, S. R., Rubio, J. C., Correia, A. E., Abrão, A. M., & Davim, J. P. (2008). Analysis of parametric influence on delamination in high-speed drilling of carbon fibre reinforced plastic composites. Journal of Materials Processing Technology, 203(1-3), 431-438. DOI:

Gemi, L., Morkavuk, S., Köklü, U., & Gemi, D. S. (2019). An experimental study on the effects of various drill types on drilling performance of GFRP composite pipes and damage formation. Composites Part B: Engineering, 172, 186-194. DOI:

Geng, D., Liu, Y., Shao, Z., Lu, Z., Cai, J., Li, X., ... & Zhang, D. (2019). Delamination formation, evaluation and suppression during drilling of composite laminates: a review. Composite Structures, 216, 168-186. DOI:

Hassan, M. H., & Abdullah, J. (2019). Drilling of fibre-reinforced composites: An innovative tool design. In Hole-Making and Drilling Technology for Composites (pp. 47-62). Elsevier. DOI:

Hejjaji, A., Singh, D., Kubher, S., Kalyanasundaram, D., & Gururaja, S. (2016). Machining damage in FRPs: Laser versus conventional drilling. Composites Part A: Applied Science and Manufacturing, 82, 42-52. DOI:

Ho-Cheng, H., & Dharan, C. K. H. (1990). Delamination during drilling in composite laminates. Journal of Manufacturing Science and Engineering, Transactions of the ASME, 112(3), 236-239. DOI:

Karataş, M. A., Motorcu, A. R., & Gökkaya, H. (2020). Optimization of machining parameters for kerf angle and roundness error in abrasive water jet drilling of CFRP composites with different fiber orientation angles. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 42(4), 1-27. DOI:

Karimi, N. Z., Heidary, H., Fotouhi, M., & Minak, G. (2017). Experimental analysis of GFRP laminates subjected to compression after drilling. Composite Structures, 169, 144-152. DOI:

Kumar, D., & Singh, K. K. (2015). An approach towards damage-free machining of CFRP and GFRP composite material: A review. Advanced Composite Materials, 24(sup1), 49-63. DOI:

Liu, D. F., Tang, Y. J., & Cong, W. L. (2012). A review of mechanical drilling for composite laminates. Composite Structures, 94(4), 1265-1279. DOI:

Liu, L., Qi, C., Wu, F., Xu, J., & Zhu, X. (2018). Experimental thrust forces and delamination analysis of GFRP laminates using candlestick drills. Materials and Manufacturing Processes, 33(6), 695-708. DOI:

Liu, L., Wu, F., Qi, C., Liu, T., & Tian, J. (2018). High-frequency vibration analysis in drilling of GFRP laminates using candlestick drills. Composite Structures, 184, 742-758. DOI:

Mohan, N. S., Kulkarni, S. M., & Ramachandra, A. (2007). Delamination analysis in drilling process of glass fiber reinforced plastic (GFRP) composite materials. Journal of Materials Processing Technology, 186(1-3), 265-271. DOI:

Palanikumar, K., Srinivasan, T., Rajagopal, K., & Latha, B. (2016). Thrust Force Analysis in Drilling Glass Fiber Reinforced/Polypropylene (GFR/PP) Composites. Materials and Manufacturing Processes, 31(5), 581-586. DOI:

Panneerselvam, T., Raghuraman, S., & Vidyasundar, A. (2014). A study to minimise delamination value during drilling chopped strand mat GFRP material. International Journal of Machining and Machinability of Materials, 15(3-4), 136-146. DOI:

Prakash, M., & Dileep Aditya Dhar, P. V. S. (2018). Investigation on the effect of drilling parameters on the tool wear and delamination of glass fibre-reinforced polymer composite using vibration signal analysis. Journal of Composite Materials, 52(12), 1641-1648. DOI:

Rubio, J. C., Abrao, A. M., Faria, P. E., Correia, A. E., & Davim, J. P. (2008). Effects of high speed in the drilling of glass fibre reinforced plastic: evaluation of the delamination factor. International Journal of Machine Tools and Manufacture, 48(6), 715-720. DOI:

Silva, D. N. R. da. (2013). Image processing methodology for assessment of drilling-induced damage in CFRP. DOI:

Sorrentino, L., Turchetta, S., & Bellini, C. (2018). A new method to reduce delaminations during drilling of FRP laminates by feed rate control. Composite Structures, 186, 154-164. DOI:

Srinivasan, T., Palanikumar, K., Rajagopal, K., & Latha, B. (2017). Optimisation of delamination factor in drilling GFR–polypropylene composites. Materials and Manufacturing Processes, 32(2), 226-233. DOI:

Tabatabaeian, A., Baraheni, M., Amini, S., & Ghasemi, A. R. (2019). Environmental, mechanical and materialistic effects on delamination damage of glass fiber composites: Analysis and optimisation. Journal of Composite Materials, 53(26–27), 3671-3680. DOI:

Tsao, C. C., Kuo, K. L., & Hsu, I. C. (2012). Evaluation of a novel approach to a delamination factor after drilling composite laminates using a core-saw drill. International Journal of Advanced Manufacturing Technology, 59(5-8), 617-622. DOI:

Xu, J., Li, C., Mi, S., An, Q., & Chen, M. (2018). Study of drilling-induced defects for CFRP composites using new criteria. Composite Structures, 201, 1076-1087. DOI:




How to Cite

Ritesh Bhat, Mohan, N. ., & Sharma, S. . (2023). Revised adjusted factor for delamination measurement in drilling of composites. Journal of Current Science and Technology, 12(1), 32–42. Retrieved from



Research Article