Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Static behavior of FG-CNT polymer nano composite plate under elevated non-uniform temperature fields(Elsevier Ltd, 2013) Jeyaraj, P.; Rajkumar, I.In this paper, static behavior of functionally graded carbon nanotube reinforced polymer composite plate under non uniform elevated temperature fields has been investigated using finite element method. The effective material properties of the composite plate are obtained using the extended rule of mixture along with carbon nanotube efficiency parameters (to include size-dependent material properties). Parameter studies are carried out to analyze influence of boundary conditions of the plate, type of functional grading of the carbon nanotube and type of non uniform thermal loading on static behavior of the functionally graded carbon nanotube reinforced composite plate. It is found that static behavior of the composite plate has been significantly influenced by nature of temperature field and nature of functional grading of carbon nanotubes. Static bending deflection of the plate increases with volume fraction of the carbon nanotube except for unsymmetrical distribution of carbon nanotube. © 2013 The Authors. Published by Elsevier Ltd.Item Bending, buckling and free vibration characteristics of FG-CNT-reinforced polymer composite beam under non-uniform thermal load(SAGE Publications Ltd, 2015) Mayandi, K.; Jeyaraj, P.Bending, buckling and free vibration behaviors of functionally graded (FG) carbon nanotube (CNT)-reinforced polymer composite beam under different non-uniform thermal loads have been analyzed using finite element method. Extended rule of mixture is used to obtain effective material property of the composite. Four different types of FG beam exposed to four different assumed one-dimensional temperature distributions along the length of the beam are analyzed. Parameters studies are carried out to investigate influences of the volume fraction of the carbon nanotube, functional grading and the nature of temperature variation on bending, buckling and free vibration characteristics. It is found that bending deflection reduces with increase in volume fraction of the CNT except for unsymmetrical functional graded beam. The static bending deflection and deformed shape of the beams are significantly influenced by the nature of temperature field. The critical buckling temperature of the beam with symmetric CNT distribution (where CNTs concentration is far from the neutral axis) is greater than other beams under different temperature fields and its value is less when the beams are exposed to uniform temperature rise above ambient temperature compared to other non-uniform temperature variations. However, the critical buckling temperature is not increasing significantly with increase in volume fraction of the CNT. The fundamental buckling mode shape is not sensitive to the nature of temperature variation but bending amplitude of the buckling mode shape is significantly influenced by functional grading of CNT and volume fraction of the CNT. The natural frequency of the beams reduces significantly with increase in temperature and the free vibration mode shapes are not influenced by temperature rise, nature of temperature variation and volume fraction of the CNT. © 2013 IMechE.Item Free Vibration Characteristics of Banana/Sisal Natural Fibers Reinforced Hybrid Polymer Composite Beam(Elsevier Ltd, 2016) RAJESH, M.; Jeyaraj, P.; Nagarajan, N.Natural fibers having more advantage compared to man-made fiber, such as glass, carbon, Kevlar fiber. But due to the hydrophilic nature of natural fiber gives poor adhesion between fiber-matrix. This will decrease the properties of polymer composite. In this study influence of surface pre-treatment with sodium hydroxide and hybridization effect of natural fiber are investigated on flexural test and free vibration behavior. In this work sisal and banana natural fibers are used in short and random orientations to prepare the polymer composites using compression moulding method. From the experimentation, it is found that chemical treatment improves the mechanical and free vibration properties of polymer composites due to the enhancement of interfacial bond between fiber and matrix as the result of chemical treatment. © 2016 The Authors.Item Buckling and Free Vibration Characteristics of a Uniformly Heated Isotropic Cylindrical Panel(Elsevier Ltd, 2016) Bhagat, V.; Jeyaraj, P.; Murigendrappa, S.M.In this paper buckling and free vibration characteristics of an isotropic cylindrical panel subjected to uniform temperature rise has been investigated using finite element method. The procedure involves the determination of critical buckling temperature, which is followed by modal analysis considering pre-stress due to the thermal field in the cylindrical panel. Detailed studies are carried out to analyze the influence of curvature ratio, thickness ratio and aspect ratio on the critical buckling temperature and free vibration behavior of an isotropic cylindrical panel. It has been found that as the curvature ratio and the thickness ratio increases the thermal buckling strength of the cylindrical panel decreases. It has also been found that free vibration frequencies reduce with an increase in temperature and the reduction is more significant for the lowest frequency mode. It is observed that free vibration mode shapes at ambient temperature changes with an increase in temperature. © 2016 The Authors.Item Effect of Core Topology on Vibro-acoustic Characteristics of Truss Core Sandwich Panels(Elsevier Ltd, 2016) Arunkumar, M.P.; Jeyaraj, P.; Gangadharan, K.V.; Mailan Chinnapandi, M.C.L.This paper presents numerical simulation studies on effect of core topology on vibro-acoustic behaviour of truss core sandwich panels with metal facings. Free and forced vibration responses of the panels are obtained using finite element method based on the equivalent 2-dimensional models. Sound radiation characteristics of the panel are obtained using Rayleigh integral. It is found that influence of nature of core topology on sound radiation is significant in lower frequencies. It is observed that compared to trapezoidal and rectangular core, triangular core is more suitable for low frequency application and also it radiates less sound compare to trapezoidal and rectangular core. © 2016 The Authors.Item Optimization of buckling strength and fundamental frequency of uniformly heated cylindrical panel using PSO(Institute of Electrical and Electronics Engineers Inc., 2017) Bhagat, V.; Jeyaraj, P.; Murigendrappa, S.M.In the present study, thermal buckling and fundamental frequency of symmetrically laminated cylindrical panel is optimized. Fiber orientation is considered as a design variable for the same. Eigenvalue buckling analysis and modal analysis is performed by using finite element method. Particle swarm optimization is used as optimization technique. MATLAB code is generated to integrate finite element method with particle swarm optimization. Finally, the influence of aspect ratio (L/S), curvature ratio (R/S), thickness ratio (R/h), effect of different weighting factors and boundary constraints on the optimum results are investigated. © 2016 IEEE.Item Buckling and Free Vibration Behavior of a Temperature Dependent FG-CNTRC Cylindrical Panel under Thermal Load(Elsevier Ltd, 2018) Bhagat, V.; Jeyaraj, P.; Murigendrappa, S.M.Present study deals with the buckling and free vibration behavior of functionally graded carbon-nanotubes reinforced composite (FG-CNTRC) cylindrical panel exposed to uniform thermal load. Stresses setup due to thermal load and temperature dependent properties influences the buckling and free vibration behavior of the heated structures. Approach employed in the present study consists of static analysis to compute thermal stresses, eigen-value buckling analysis to compute critical buckling temperature and finally modal analysis, taking thermal stresses into account. Influence of different CNTs grading pattern, CNTs volume fraction, geometric parameters, boundary constraints and temperature dependent properties on the buckling strength are investigated. It is observed that hybrid CNTs distribution pattern gives comparatively higher buckling strength and free vibration frequencies. Investigation on free vibration characteristics of the FG-CNTRC panel at elevated temperature signifies that the decline in free vibration frequencies is very drastic at a temperature close to buckling temperature along with temperature dependent properties. c 2017 Elsevier Ltd. All rights reserved. © 2018 Elsevier Ltd.Item Dynamic impact behavior of syntactic foam core sandwich composites(DEStech Publications Inc. info@destechpub.com, 2018) Breunig, P.; Damodaran, V.; Shahapurkar, K.; Waddar, S.; Doddamani, M.; Jeyaraj, P.; Mohan Kumar, G.C.M.; Prabhakar, P.Sandwich composites and syntactic foams have historically been used in many engineering applications to meet the needs of a system. However, there has been minimal effort to take advantage of the weight saving ability of syntactic foams in the cores of sandwich composites, especially with respect to the impact response of the structure. The goal of this experimental study is to investigate the mechanical response and damage mechanisms associated with sandwich composites with syntactic foam cores. The core was manufactured using epoxy resin as the matrix and cenospheres as the reinforcement with varying volume fractions of 0%, 20%, 40%, and 60%. The sandwich composites were manufactured with the vacuum assisted resin transfer molding (VARTM) process. Impact tests were performed on the specimens according to ASTM D7766 at two energy levels: 80J and 160J. The data from the tests was post-processed to gain quantitative understanding of the damage mechanisms present in the specimens. A qualitative understanding was obtained through MicroCT scanning imaging. The analysis showed that increasing the volume fraction of cenospheres in the syntactic foam made the damage mechanism more desirable, even at high energy levels. © 2018 by DEStech Publications, Inc. All rights reserved..Item A novel approach to determine the thermal transition of gum powder/hydro-gels using dynamic mechanical analysis(American Institute of Physics Inc. subs@aip.org, 2018) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.The dynamic characterization of materials plays a major role in the present area. The many researchers are worked on solid materials and its characterization, it can be tested using dynamic mechanical analyzer (DMA), however, no such work on powder a semiliquid samples. The powder and liquid samples can also easily characterization as like solid samples using DMA. These powder samples are analyzed with a material pocket method which can be used to accurately determine very low levels of variation in powder properties, due to the high sensitivity of DMA to glass transitions. No such DMA studies on hydrogel and Gum powders. The gum powders are used in various applications start from food industries, pharmacy, natural gums paste, biomedical applications etc. among all this applications gum Ghatti is one of the powders using for varies applications. Around 50 milligrams of Ghatti powders are placed inside material pocket and analyzed storage modulus (G′), loss modulus (G″) and tan delta (δ). Also, understand the curing and glass transition effect using water, glycerin and superplastic from room temperature to 200°C. The result shows that storage modulus decreases with increase in temperature in pure Ghatti powder. The surprising improvement in storage modulus was found with an increase in temperature with addition of water, glycerin, and superplastic. However, loss modulus and tan delta are also having very significant influence and also shows a clear peak of the tan delta. The loss modulus results were found to be improved by adding solidifying agents, along with this water and superplastic better influence. But glycerine found to be hydrogel in nature and thermodynamic properties are much influenced by frequency. © 2018 Author(s).Item Effect of stacking sequence on mechanical properties neem wood veneer plastic composites(American Institute of Physics Inc. subs@aip.org, 2018) Nagamadhu, M.; Mohan Kumar, G.C.; Jeyaraj, P.This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images. © 2018 Author(s).