PSI - Issue 14

T Sreekantha Reddy et al. / Procedia Structural Integrity 14 (2019) 265–272 Author name / Structural Integrity Procedia 00 (2018) 000–000

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Table 3. Front and rear side damage areas of all laminates impacted at 100 J energy and determined from IR thermography (Values in the bracket are calculated from visual observation) Thickness (mm) 3mm 5mm 7mm 10mm Front damage area (cm 2 ) 10.1 17.7 39.9 18 Rear damage area (cm 2 ) 12.76 ( 6.7) 16.6 (10.5) 29.1 (35.0) 24.8 (17.0) 4. Conclusions E-glass/epoxy composite laminates were subjected to low velocity impact and the effect of laminate thickness on impact parameters like peak force, maximum displacement, absorbed energy and damage area was experimentally evaluated. Peak force is highly sensitive to thickness of laminate, it has increased by 0.97 times, 1.79 times and 2.67 times for 5mm, 7mm and 10mm laminates, respectively over that of 3mm thick laminates. Maximum displacement has decreased with increase in laminate thickness. It was found that maximum displacement of 7mm and 10mm laminates has decreased about 28% and 50%, respectively over that of 5mm thick laminates when impacted at 100J energy. Absorbed energy and contact duration were decreased with increase in thickness. Visual observation of impacted laminates suggests that two types of damage regions namely fibre breakage area and delamination area were present but the contribution of these two types for total damage area is found to be thickness dependent. Acknowledgements Authors gratefully acknowledge Dr. Vikas Kumar, Director, Defence Metallurgical Research Laboratory (DMRL), Hyderabad for his encouragement to publish this work. The authors also acknowledge the support rendered by the staff of Armour Design and Development Division (ADDD). References ASTM D7136 / D7136M, 2007. Standard test method for measuring the damage resistance of a fiber-reinforced polymer matrix composite to a drop-weight impact event. p.1-16., West Conshohocken, PA. Baucom, J.N., Zikry, M.A., Rajendran, A.M., 2006. Low-velocity impact damage accumulation in woven S2-glass composite systems. Composite Science & Technology 66, 1229–38. Belingardi, G., Vadori, R., 2002. Low velocity impact tests of laminate glass-fibre-epoxy matrix composite material plates. International Journal of Impact Engineering 27, 213–29. Bogdanovich, A.E., Friedrich, K., 1994. Initial and progressive failure analysis of laminated composite structures under dynamic loading. Composite Structures 27, 439–56. Cantwell, W., Curtis, P., Morton, J., 1983. Post impact fatigue performance of carbon fibre laminates with non-woven and mixed-woven layers. Composites 14(3), 301–5. Cantwell, W.J., Curtis, P.T., Morton, J., 1984. Impact and subsequent fatigue damage growth in carbon fibre laminates. International Journal of Fatigue 6(2), 113–8. Karakuzu, R., Erbil, E., Aktas, M., 2010. Damage prediction in glass/epoxy laminates subjected to impact loading. Indian Journal of Engineering & Material Science, 17, 186-98. Ley, O., Godinez, V., 2013. Non-destructive evaluation (NDE) of aerospace composites: application of infrared (IR) thermography, Woodhead Publishing Limited, pp 309. Naik, N.K., Sekher, Y.C., 1998. Damage in laminated composites due to low velocity impact. Journal of Reinforced Plastics & Composites 17(14), 1232–63. Rama Subba Reddy, P., Sreekantha Reddy, T., Mogulanna, K., Madhu, V., 2016. Studies on behaviour of armour grade composites subjected to low and high velocity impacts. DMRL technical report No.: DRDO-DMRL-ADDG-118-2016. Shen, W.Q., 1997. Dynamic response of rectangular plates under drop mass impact. International Journal of Impact Engineering,19(3), 207–29. Sreekantha Reddy, T., Rama Subba Reddy, P., Madhu, V., 2016. Influence of hybridization on the performance of glass composites under low and high velocity impact, Advanced Material Letters 7(6), 491-6. Sreekantha Reddy, T., Rama Subba Reddy, P., Madhu, V., 2017. Response of E-glass/epoxy and Dyneema® composite laminates subjected to low and high velocity impact. Procedia Engineering 173, 278 – 85. Sutherland, L.S., Soares, C.G., 1999. Impact tests on woven-roving E-glass/polyester laminates. Composite Science & Technology 59, 1553-67. Yang, F.J., Cantwell, W.J., 2010. Impact damage initiation in composite materials. Composite Science & Technology 70, 336–42.