Research Article Impact Response of Quasi-Isotropic Asymmetric Carbon Fabric/Epoxy Laminate Infused with MWCNTs Nand Kishore Singh, Prashant Rawat, and K. K. Singh Department of Mechanical Engineering, Indian School of Mines (ISM), Dhanbad 826004, India Correspondence should be addressed to Nand Kishore Singh; incredablespace@gmail.com Received 8 March 2016; Revised 24 June 2016; Accepted 14 July 2016 Academic Editor: Wei Zhou Copyright © 2016 Nand Kishore Singh et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Efect of embedding multiwalled carbon nanotubes (MWCNTs) on low velocity impact response of quasi-isotropic asymmetric laminate of plain woven carbon fabric/epoxy was investigated. Laminates were embedded with 0 wt.%, 2 wt.%, and 5 wt.% MWCNTs to improve impact resistance. Impact in laminates was conducted according to ASTM D7136 standard at an impact energy of 94.14 J corresponding to the impact velocity of 6 m/sec. Energy-time response, force-time response, and pyramidal damage area of laminates doped with varying weight percentage (wt.%) of MWCNTs were quantiied and compared with laminate without MWCNTs. Absorbed impact energy increases by 13.53% on doping of 2 wt.% MWCNTs, whereas it decreases by 10.49% on doping 5 wt.% MWCNTs. Damage area is reduced on doping 2 wt.% MWCNTs in laminate. 1. Introduction he properties like high strength, high stifness, and low density have increased the demand of iber reinforced poly- mer (FRP) composites. FRP composites have emerged as an alternative to traditional engineering materials and have wide scale application in aerospace, militaries, and automobiles sectors. However, high damage susceptibility of FRPs towards impact because of weak interface between plies is a concern for the application of FRPs. Weak interface causes delami- nation and matrix crack age leading to iber failure. here- fore, many researchers have reported various modiications (design, hybrid combination, carbon nanotubes doping, etc.) in order to enhance the impact resistance of FRP laminates. Karakuzu et al. [1] and Menna et al. [2] used GFRP lami- nates of diferent layup to analyze their impact characteriza- tion by simulating inite element models. Sevkat et al. [3] investigated the low velocity impact response of plain woven hybrid glass-graphite toughened epoxy composite. he stacking sequences of hybrid composite are glass fabric skin with graphite fabric as core and graphite fabric skin with glass fabric core. Gopinath et al. [4] emphasized two opposing inluence of matrix on ballistic performance of the armor. Matrix engages more yarns and prevents their relative sliding which improves ballistic performance. On the contrary to this, it also reduces lexibility and interaction among various layers which reduces ballistic performance. Jiang and Shu [5] investigate the efect of internal sheet involved in two-layer sandwich composites, subjected to low velocity impact. Ghasemnejad et al. [6] fabricated hybrid composite beam by using glass/epoxy and carbon/epoxy composite. For improv- ing impact response, hybrid composite beams were pinned by natural lax yarns before curing process. Addition of lax -pinning leads to improvement in impact resistance because it arrests the crack propagation. N. K. Singh and K. K. Singh [7] and Agarwal et al. [8] had done review on FRP (iber reinforced polymer) laminates impacted by diferent type of impactor with varying velocity at diferent impact locations. Efect of boundary conditions, core type, and transverse reinforcement were also analyzed. Allaoui et al. [9] synthe- sized composite of MWCNTs and epoxy by varying weight percentage of MWCNTs. Double and quadruple increase in Young’s modulus and yield strength was observed on addition of 1 wt.% and 4 wt.% MWCNTs. Transition of composite from insulator to conductor was observed by addition of 0.5 wt.% to 1 wt.% of MWCNTs. Ci and Bai [10] studied the reinforce- ment role of carbon nanotubes (CNTs) in epoxy composites with diferent matrix stifness. In sot and ductile matrix, Hindawi Publishing Corporation Advances in Materials Science and Engineering Volume 2016, Article ID 7541468, 7 pages http://dx.doi.org/10.1155/2016/7541468