International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 05 Issue: 05 | May-2018 www.irjet.net p-ISSN: 2395-0072 © 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 180 DAMAGE ASSESSMENT OF CFRP AND GFRP LAMINATES SUBJECTED TO LOW VELOCITY IMPACT Dipu Kumar 1 , AdithyaKrishna K R 2 , Aditya Deepak 3 1,2,3 B.TECH student, Department of Mechanical Engineering, PES UNIVERSITY, Karnataka, India -----------------------------------------------------------------------***----------------------------------------------------------------------- Abstract - Polymer Composite laminates are fast replacing structural heavy metals such as Cast Iron and steel because of their high strength to weight ratio, higher stiffness to weight ratio, improved fatigue resistance, improved corrosion re- sistance, higher resistance to thermal expansion and simplicity of manufacture. It is a common knowledge that due to high heterogeneity, these laminates have very poor low velocity impact behavior. To enable design of critical components of aero- space and automotive parts, it is necessary to thoroughly understand the mechanism of damage and suitably arrive at the constituents of the laminate layers. This paper presents the experimental study of damage behavior on glass fiber reinforced polymer and carbon fiber reinforced polymer of varied thickness (1 mm and 2 mm) subjected to low velocity impact test at different impact energy levels. Drop/falling weight impact method is conducted as per ASTM D7136 and the incident impact energy is varied by varying the height of the indenter and keeping the mass of the indenter constant. Composite laminates are prepared using Vacuum bag- ging process and is cured at room temperature. Bi-Woven cloth of 20 GSM is used as the fiber phase and Epoxy resin is used as the Matrix phase. For each level of impact energy, parameters such as absorbed energy, initial and degraded stiffness, peak- absorbed load, deflection at peak load, damage area and maximum damage diameter were determined. For characterizing and understanding the damage process of the impacted specimen, various Non-Destructive testing methods such as Visual Inspection, Radiography and Ultrasonic A-Scan tests are conducted. Key Words: Glass Fiber Reinforced Polymer, Carbon Fiber Reinforced Polymer, Low Velocity Impact, Drop weight Impact Method, Damage Assessment Non-Destructive Technique (NDT) Testing INTRODUCTION Glass Fiber reinforced polymers (GFRP) Glass Fiber reinforced polymers is a fiber strengthened plastic made from glass fibers. GFRP is cheaper and more flexible than CFRP. GFRP are used in boats, automobiles, bathtubs, and enclosures [1]. Carbon Fiber reinforced polymers (CFRP) Carbon fiber reinforced polymer (CFRP) is a fiber reinforced plastic made from carbon fibers. Carbon fiber reinforced pol- ymer (CFRP) is extremely strong and have high strength to weight ratio. Properties of CFRP rely upon the formats of the carbon fiber and the extent of carbon fiber with respect to polymer matrix [1]. Fabrication of Laminates The laminates of glass fiber reinforced polymer (GFRP) and Carbon fiber reinforced polymer (CFRP) of 1mm and 2mm thickness were set up by Hand Lay-Up process, following by vacuum bagging method to remove the entrapped air and overabundance resin. The resin used is epoxy resin with fiber orientation in 0 and 90 degrees. In the Hand Lay-Up process, liquid resin is poured into the mold and the reinforcement is placed on the top. A roller is used to impregnate the fibers with resin. Similarly, different layers of resin and reinforcement layer is applied to make a laminate of required thickness. The laminates prepared by Hand Lay-Up process are further processed by vacuum bagging technique and are cured at room temperature. The laminates sheets once cured are cut into dimension of 150X150 mm with the help of diamond cutter. Low velocity Impact loading Impact is defined as a high force or shock applied over a short period of time. The best example for impact is the collision of two bodies. When the two bodies encounter each other, they develop a contact force. In the case of drop weight impact test, when the indenter is impacted on the target, contact force is developed[7]. Impact is classified as low, intermediate, high and hyper velocity. Low velocity impact is one of the causes of damage in composite structures [3]. Low velocity im-