www.tjprc.org editor@tjprc.org INFLUENCE OF FIBER ORIENTATION ON THE PROPERTIES OF COMPOSITES M. ASHOK KUMAR 1 , K. DEEPAK 2 , CH. V. K. N. S. N. MOORTHY 3 & B. SUBRAMANYAM 4 1, 2 Department of Mechanical Engineering, Vardhaman College of Engineering, Hyderabad, India 3 Department of Mechanical Engineering, Institute of Aeronautical Engineering, Hyderabad, India 4 Department of Mechanical Engineering, MLR Institute of Technology, Hyderabad, India ABSTRACT Damage pattern on the surface of laminate with fiber orientations (0 0 /15 0 ), (0 0 /30 0 ), and (0 0 /45 0 ) have been studied. E-glass/Epoxy composite laminate of thickness 4mm with size 100mmx100mm clamped on all the edges has been used. The laminate is subjected to quasi-static indentation at center with 8 mm diameter steel ball indenter. Damage is quantified in terms of opacity of the indented area, that represent delaminations, debonds and fiber fracture. Results indicated that damage is directly proportional to the fiber angle and also the internal damage is limited to the surrounding area of indentation spot. Observations from scanning electron micrographs have been correlated with visual observations. KEYWORDS:Delamination, Epoxy, Fiber,Indentation & Laminate Received: Nov 22, 2017; Accepted: Dec 18, 2017; Published: Jan 08, 2018; Paper Id.: IJMPERDFEB201854 INTRODUCTION Fiber-reinforced composites are widely used in shipbuilding, aerospace and other commercial applications whenever high specific modulus, low specific weight, and damage tolerance are needed. The composites play significant role of absorbing energy due to intralaminar and interlaminar damage mechanisms like matrix crack, delamination, and fiber breakage. Therefore, estimation of penetration resistance, damage and energy absorption has become difficult. Sun et al. [1] presented that the damage mechanism in low velocity impact is same as that of quasi-static loading. The indenter displacements for damage in static and dynamic loading were comparable. Due to difference in strain rate the degree of damage per unit time was different. Johnson et al. [2] developed a computation method based on CDM model to predict impact damage of composite structures. Yen et al. [3] presented a damage model by generalizing the layer failure model in LS-DYNA. The load-displacement curve presented by Sun et al. [4] shows a small drop in load indicating the initiation of delamination in the laminate. The increase in load exhibits an oscillatory nature during the progress of delamination. After reaching the peak load, it drops suddenly to a minimum value and stays at that level. This corresponds to the friction that develops between punch and laminated plate. The damage mechanism approach incorporate softening behavior and progressive damage of a laminate after damage initiation. Matzenmiller et al. [5]. Williams et al. [6] used principles of damage mechanism along with the fiber and matrix failure criteria to analyse damage in low velocity loading. Load- displacement curves and damage patterns were comparable with the experimental results. Original Article International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN (P): 2249-6890; ISSN (E): 2321-8001 Vol. 8, Issue 1, Feb 2018, 487-494 © TJPRC Pvt. Ltd.