Faculty Publications
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Item Sound radiation and transmission loss characteristics of a honeycomb sandwich panel with composite facings: Effect of inherent material damping(Academic Press, 2016) Arunkumar, M.P.; Jagadeesh, M.; Jeyaraj, J.; Gangadharan, K.V.; Mailan Chinnapandi, M.C.L.This paper presents the results of numerical studies carried out on vibro-acoustic and sound transmission loss behaviour of aluminium honeycomb core sandwich panel with fibre reinforced plastic (FRP) facings. Layered structural shell element with equivalent orthotropic elastic properties of core and orthotropic properties of FRP facing layer is used to predict the free and forced vibration characteristics. Followed by this, acoustic response and transmission loss characteristics are obtained using Rayleigh integral. Vibration and acoustic characteristics of FRP sandwich panels are compared with aluminium sandwich panels. The result reveals that FRP panel has better vibro-acoustic and transmission loss characteristics due to high stiffness and inherent material damping associated with them. Resonant amplitudes of the response are fully controlled by modal damping factors calculated based on modal strain energy. It is also demonstrated that FRP panel can be used to replace the aluminium panel without losing acoustic comfort with nearly 40 percent weight reduction. © 2016 Elsevier LtdItem Mechanical Properties of Natural Fiber Braided Yarn Woven Composite: Comparison with Conventional Yarn Woven Composite(Science Press bcanji@mail.sioc.ac.cn, 2017) RAJESH, M.; Jeyaraj, J.The effect of reinforcing natural fiber in the form of braided yarn woven fabric on mechanical properties of polymer composite was investigated. The results of braided yarn fabric composites were compared with the conventional yarn fabric composite and random oriented intimately mixed short fiber composites for the same percentage of fiber weight. The effect of intra-ply hybridization, by keeping two different natural fiber yarns along two different directions of a woven fabric, on mechanical properties of the woven fabric composite was also analyzed. Natural fiber braided yarn fabric reinforcement significantly increased the mechanical properties of the composites compared with that of the conventional woven fabric and short fiber reinforcements. Intra-ply hybridization of two different natural fibers improved the mechanical properties of the conventional woven fabric composite while it could not enhance the properties of the braided fabric composite. The improvement in impact property is very high compared to tensile and flexural properties due to the braided yarn fabric reinforcement. © 2017 Jilin UniversityItem Influence of textile properties on dynamic mechanical behavior of epoxy composite reinforced with woven sisal fabrics(Springer, 2020) Nagamadhu, M.; Jeyaraj, J.; Mohan Kumar, G.C.Due to low cost and environmentally friendly characteristics, natural fibers gain much attention over synthetic fiber. The aim of the present work is to characterize the textile properties of three different types of sisal fabric and study dynamic mechanical properties and water absorption behavior of the sisal fabric reinforced epoxy composite. Influence of grams per square meter of fabric, weaving pattern of the fabric on textile properties of the fabric is studied first. Further, the effect of the same on the dynamic mechanical properties of the sisal composites is studied. Effect of fiber weight percentage and dynamic frequency on dynamic mechanical properties also studied. Results reveal that the storage modulus (G?) decreases with increasing temperature in all the woven types of composites under consideration. However, Plain 2 (P2) and Weft Rib (WR) composites have shown better values of G? even after the glass transition temperature (Tg). From the results, it is also evident that storage and loss modulus (G??) increases when the yarn diameter decreases which is observed at a higher temperature also. It is also observed that fabric density also plays a significant role in the enhancement of G? and G?? values. The water absorption of Plain 1 (P1) based composites are found to be less compared to the other types of composites analyzed. © 2020, Indian Academy of Sciences.Item Fracture toughness of flax braided yarn woven PLA composites(Bellwether Publishing, Ltd., 2021) Kanakannavar, S.; Jeyaraj, J.Flax fiber braided yarn plain woven fabric reinforced Poly Lactic Acid (PLA) bio-composites are fabricated using film stacking and hot-press compression molding method. Effect of fiber weight fraction on tensile and fracture properties of the bio-composites is studied and fractured surfaces are analyzed using scanning electron microscope (SEM) images. It is found that tensile modulus and strength increases by 62.11 and 59.75% respectively for 35 wt.% of the braided fabric reinforcement compared to pristine PLA. Fracture toughness study is performed on single-edge-notched-bend (SENB) specimens using three point bending method. It is found that plane-strain fracture toughness (KIC) and strain energy release rate (GIC) values of the PLA composites are 71.61 and 124% higher than pure PLA for 35 wt.% braided fabric reinforcement. KIC values of the braided fabric reinforced PLA composites are much high compared to similar natural fiber composites reported in literature. This is attributed to high resistance offered by the interweaving yarns of the braided fabric hence more energy is required to begin crack propagation compared to other typical forms of reinforcement. © 2021 Taylor & Francis Group, LLC.Item Free vibration and stability of graphene platelet reinforced porous nano-composite cylindrical panel: Influence of grading, porosity and non-uniform edge loads(Elsevier Ltd, 2021) Twinkle, T.; Jeyaraj, J.Buckling and vibration characteristics of functionally graded(FG) porous(P), graphene platelet (GPL) reinforced cylindrical panel are presented. A multilayer model is considered for analysis with graphene and internal pores distribution varying in an uniformly or two different non-uniformly manner along the thickness. To evaluate the effective mechanical properties, extended rule of mixture together with modified Halpin-Tsai micromechanics model and mechanical properties of open-cell metal foams is used. Considering a higher order shear deformation theory, characteristics of the FG-P-GPL reinforced cylindrical panel under different edge loads such as uniform, triangular, trapezoidal and parabolic are investigated. The Hamilton's principle is used to formulate the governing partial differential equations and buckling and free vibration solutions are obtained by employing the Galerkins method. The influences of grading of GPL and internal pores, porosity coefficient on buckling and dynamic characteristics of functionally graded GPL reinforced porous cylindrical panel under uniform and non-uniform in-plane loads are presented. © 2020 Elsevier LtdItem Thermal buckling of braided flax woven polylactic acid composites(SAGE Publications Ltd, 2021) Kanakannavar, S.; Jeyaraj, J.This study presents influence of thermal environment on buckling behaviour of natural fibre braided yarn fabric reinforced polylactic acid composite beams. The thermal buckling study is carried out using an in-house built experimental set up for beam like composites exposed to different types of in-plane temperature variations. Influences of temperature variations, direction of loading and volume fraction of fibre are studied in detail. Results indicate that deflection behaviour of natural fibre braided fabric/polylactic acid beam is entirely different from the polylactic acid beam. Enhancement of natural fibre braided fabric reinforcement on thermal deflection is observed only at higher temperature as less deflection is observed for polylactic acid beams at lower temperature range (25°C to 45°C). According to the nature of heating, maximum deflection in the range of 0.503 cm to 1.082 cm corresponding to the temperature range of 63.443°C to 67.917°C is observed for polylactic acid beams. For natural fibre braided fabric/polylactic acid beams, the maximum deflection range is 0.826 cm to 0.105 cm corresponding to the temperature range of 57.031°C to 44.742°C according to the heating condition. Thermal deflection of natural fibre braided fabric beam is sensitive to testing orientation of the beam and maximum deflection for warp loading is 29% to 54% lower than the weft loading. © The Author(s) 2020.Item Tribological behaviour of natural fibre 3D braided woven fabric reinforced PLA composites(SAGE Publications Ltd, 2021) Kanakannavar, S.; Jeyaraj, J.; Ramesh, M.R.This study aims to investigate the potential of natural fibre 3D braided woven fabric (NFBF) reinforced PLA (poly lactic acid) composites for tribological applications. Composites with different fibre contents are prepared using film stacking process and hot press methods. Friction co-efficient and wear rate of the composites are analysed using pin-on-disc tribometer under dry contact sliding condition and various operating conditions (velocity and load) for a fixed sliding distance of 3000 m. The morphology of the worn surfaces is studied using scanning electron microscope (SEM). The reinforcement of fibre with the PLA reduced the polymer film generation and improved the surface roughness significantly. Wear rate of the composites are decreased drastically compared to pure PLA. Composite with 35 wt.% of NFBF reinforcement showed better wear characteristics. © IMechE 2020.Item Acoustic fluid–structure study of 2D cavity with composite curved flexible walls using graphene platelets reinforcement by higher-order finite element approach(Elsevier Ltd, 2021) Jeyaraj, J.; Gupta, P.; Vasudevan, V.; Polit, O.; Manickam, G.In the present study, acousto-vibration analysis of 2D fluid-filled cavities/tanks having flat and curved flexible walls is made using a trigonometric function based shear deformable theory and the Helmholtz wave model for fluid domain. The governing equation formed here is solved through higher-order finite element approach. The walls are modeled by C1 continuous 3-noded beam element and the fluid is idealized using an eight-noded quadrilateral element. Structural and coupled frequencies are evaluated for fluid-filled cavities with rigid/flexible vertical walls along with flat/curved beam on top. The sound pressure level is also predicted in the fluid domain due to a steady-state mechanical harmonic load on the top of the cavity. This investigation is conducted for metallic cavities and then extended to graphene platelets reinforced cavity. The effect of degree of fluid–structure coupling is examined assuming different fluid domains. Considering a wide range of cavity geometry and material parameters such as thickness ratio, curved beam angle, graded porosity and graphene platelets, porosity coefficient, loading of GPL, fluid medium, a comprehensive investigation is depicted to highlight their impacts on vibro-acoustic nature of fluid-filled cavities. It is observed that the dynamic characteristics of rigid and flexible wall cavities are significantly different from each other. © 2021 Elsevier LtdItem Fabrication and mechanical properties of braided flax fabric polylactic acid bio-composites(Taylor and Francis Ltd., 2022) Kanakannavar, S.; Jeyaraj, J.This paper primarily describes the development of flax braided yarn fabric reinforced thermoplastic composites. Plain woven fabric is made by interlacing 3D braided yarn produced by solid braiding method. Tensile properties of braided yarn and woven fabric are evaluated. Solution casting is used prior to composite fabrication to prepare polylactic acid (PLA) and (natural fiber braided fabric) NFBF–PLA sheets. Followed by this, composite laminates are prepared using through film stacking and compression molding. Influence of number of layers of fabric and loading along warp and weft directions on mechanical properties such as tensile, flexural and impact properties are presented. It is observed that the reinforcement enhances the tensile, flexural and impact properties of the composite significantly for the warp loading. Results also clearly indicates that braided yarn fabric reinforcement have the potential for significant improvement of mechanical and thermal properties of PLA composites. © 2021 The Textile Institute.Item A semi-analytical nonlocal elasticity model for static stability and vibration behaviour of agglomerated CNTs reinforced nano cylindrical panel under non-uniform edge loads(Elsevier Inc., 2022) Twinkle, C.M.; Jeyaraj, J.A semi analytical nonlocal elasticity model to analyze the effect of non-uniform edge loads on static stability and free vibration characteristics of agglomerated carbon nanotubes (CNTs) reinforced nano cylindrical panels are presented. Effective material properties of the agglomerated CNT reinforced composite are obtained using a two-parameter micro-mechanics model while Eringen's non-local theory is used to account the size effect. Sinusoidal shear deformation theory is adopted to analyze the buckling and vibration parameters using Galerkin's approach. The accuracy of the proposed model is presented first by comparing the results in the literature. Then a comprehensive study is carried out to analyze the influence of various degrees of agglomeration (complete, partial), nature of edge load, and non-local effects on the buckling and free vibration response of CNT reinforced nano cylindrical panel. The results revealed that non-local size effect leads to a reduction in stiffness and thus reduces buckling and dynamic characteristics. Moreover, it is observed that critical buckling load varies with type of in plane load and reduction in natural frequency is different for different in plane loading conditions. © 2021 Elsevier Inc.