Conference Papers
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Item Thermal properties of maize fiber reinforced unsaturated polyester resin composites(2013) Saravana Bavan, B.D.; Mohan, K.G.C.Increase in demand for natural fiber composites are raising today because of more advantage when compared to traditional fiber composites. In the present work, natural fiber composite material is processed by vacuum assisted resin transfer molding technique and the fibers are maize stalk fibers with matrix of unsaturated polyester resin. With suitable catalyst and accelerator composite material is fabricated and thermal properties for the material is examined by thermal gravimetric analyzer, differential scanning calorimeter and the results are also compared with finite element method.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 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 Determination of apparent coupling factors for adhesive bonded acrylic plates using SEAL approach(American Institute of Physics Inc. subs@aip.org, 2018) Pankaj, A.C.; Shivaprasad, M.V.; Murigendrappa, S.M.Apparent coupling loss factors (CLF) and velocity responses has been computed for two lap joined adhesive bonded plates using finite element and experimental statistical energy analysis like approach. A finite element model of the plates has been created using ANSYS software. The statistical energy parameters have been computed using the velocity responses obtained from a harmonic forced excitation analysis. Experiments have been carried out for two different cases of adhesive bonded joints and the results have been compared with the apparent coupling factors and velocity responses obtained from finite element analysis. The results obtained from the studies signify the importance of modeling of adhesive bonded joints in computation of the apparent coupling factors and its further use in computation of energies and velocity responses using statistical energy analysis like approach. © 2018 Author(s).Item A comparison of the non-conforming and conforming sector finite element for free vibration of circular discs(Elsevier Ltd, 2020) Avvaru, H.T.; Joladarashi, S.; Kadoli, R.A twelve-term non-conforming and a sixteen-term conforming displacement polynomial are obtained from Pascal's triangle to deduce the shape functions for a sector element. Using the sector element circular disc is discretized. The number of degrees of freedom for the sector element at a given node is three and four. Kirchhoff's plate theory is the basis for strain energy and kinetic energy because of the transverse motion of the circular plate. Associated stiffness and mass matrices for the sector element are derived in closed form using MATHEMATICA. Using the Lagrange equation, the free vibration equation of motion for the circular disc is derived. A validation study is conducted, and non-dimensional frequencies from the finite element solution are compared with the analytical solutions reported in the literature. Subsequently, the natural frequencies of Al-Al2O3functionally graded circular disc with gradation in the thickness direction are evaluated for a variety of boundary conditions. © 2020 Elsevier Ltd. All rights reserved.Item Buckling analysis of functionally graded materials by dynamic approach(Elsevier Ltd, 2020) Swaminathan, K.; Hirannaiah, H.; Rajanna, T.Laminated composites exhibit difference in the mechanical properties at the interface between two materials resulting in stress concentration. This may lead to damages in the form of delamination, matrix cracking and adhesive bond separation. Functionally Graded Materials (FGM) are formed by gradual variation of two or more material over a particular volume, thereby overcomes these issues. Buckling problems of FGM plates are usually solved by static approach. In some cases, particularly non-uniform loading and geometric discontinuity, the stress concentration usually occurs. In such cases, the solution to the buckling problem by dynamic approach is most suitable. In the dynamic approach, the natural frequencies are calculated by applying in-plane loads. As the intensity of the in-plane load increases, the frequency of the material decreases and finally becomes zero at the onset of buckling. The load at which the natural frequency becomes zero that load is called a buckling load. In this investigation, the vibration and buckling characteristics of FGM panels subjected to uniaxial and biaxial loading conditions have been studied by using the finite element method (F.E.M). In the Finite element (FE) formulation, the effective material properties of FGM plates are assumed to vary in the thickness direction according to the power-law distribution of volume fraction of the constituents. The plate is modelled by using 8-noded serendipity element by incorporating the effect of transverse shear deformation and rotary inertia. The effect of different parameters such as volume fraction index (n), the thickness of the panel (h) and boundary condition of the plate are considered to study the buckling behaviour of the FGM plate under uniaxial loading conditions. © 2020 Elsevier Ltd. All rights reserved.Item Effect of initial stresses on vibration behavior of functionally graded materials(Elsevier Ltd, 2020) Swaminathan, K.; Hirannaiah, H.; Rajanna, T.Functionally Graded Materials (FGM) is the result of continuous gradation of two or more constituent materials over a certain volume. This type of material overcomes many problems, particularly delamination, cracking and damages which are very frequently found in laminated composite materials. The FGMs are commonly found in space structures, and these structural elements are subjected to various kinds of loadings during its service period, in which in-plane loading is the one which significantly affects the vibration characteristics of the structural elements. In this investigation, the effect of tensile and compressive stresses on vibration characteristics of FG panels has been studied by using finite element technique (FE). For mathematical modelling Poisson's ratio is assumed constant and Young's modulus of elasticity is assumed to vary according to the power-law distribution of volume fraction of the constituents. The plate is modelled by using 8-noded isoparametric element by considering the effect of transverse shear deformation and rotary inertia. The effect of different factors such as volume fraction index, the thickness of the panel, boundary condition and tensile as well as compressive edge loads are considered to study the vibration behaviour of the FGM plate under tensile and compressive uniaxial edge loads. © 2020 Elsevier Ltd. All rights reserved.Item Seismic Response of Basal Geogrid Reinforced Embankments Supported on a Group of Vertical and Batter Piles(Springer Science and Business Media Deutschland GmbH, 2021) Patel, R.M.; Jayalekshmi, B.R.; Shivashankar, R.; Surya, N.R.Basal geogrid reinforced embankments supported on vertical piles are proven to be a feasible and effective solution for constructing embankments over thick soft clay deposits and bridge approaching embankments. These solutions minimize the lateral displacements, total and differential settlements of embankment crest and toe by transmitting embankment loads into the deeper stratum through pile foundations and arching action of geogrid. Basal geogrid reinforcements provide good restraint against lateral spreading of the toe. Providing batter piles near the toe will further enhance this restraint against lateral spreading. Not many studies are available in literature on performance of batter piles below embankment toe, especially under seismic excitations. The present study aims to find the advantages of providing batter piles below embankment toe under seismic excitations. A 6 m high basal geogrid reinforced embankment having 1 V:1.5H side slope constructed over 28 m thick soft clay is considered for the 3-Dimensional finite element analysis. The soft clay is stabilized with 22 m long 300 mm diameter vertical and batter piles spaced at three times the pile diameter. Embankment crest vertical displacements, toe horizontal displacements, maximum differential settlements at the crest and crest lateral accelerations are analysed for different batter angles of 0°, 5°, 10°, 15°. Analysis of results reveals that larger the batter angle more is the reduction of toe horizontal displacements. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Assessment of Effect of Deep Excavation on Adjacent Structures Using Finite Element Analysis(Springer Science and Business Media Deutschland GmbH, 2022) Hulagabali, A.M.; Bariker, P.; Solanki, C.H.; Dodagoudar, G.R.Deep excavations and its impact on neighboring buildings is one of the most important issues when planning to construct new facility. In metropolitan city, it’s a challenging task for the execution of underground construction due to limited space and high cost of land. Hence, this implies that deep excavation has become necessary for the proper utilization of available space. Therefore, it’s important to make sure that adjacent structures are safe against deep excavation-induced deformation. In this study, a two-dimensional Finite Element Method in PLAXIS 2D has been chosen for the soil–structure analysis of deep excavation supported by contiguous pile wall located in Addis Ababa. For the numerical analysis two constitutive models Mohr–Coulomb and Hardening Soil have been applied in drained effective stress condition. The objective of this study is to investigate the effect of deep excavation on adjacent structures by considering support stiffness, ground water condition, neighboring building distance from face of excavation, and building load. The analysis of this study monitors parameters like maximum lateral wall deflection (δhm), maximum settlement (δvm), angular distortion of the neighboring structures, horizontal strain, and maximum bending moment of contiguous pile wall. Moreover, normalization of lateral wall deflection (δhm/He) and settlement (δvm/He) to the excavation depth (He) and neighboring building distance-excavation (D/He) has been presented. Parametric studies have been carried out by varying parameters of diameter of contiguous pile wall, horizontal anchor spacing, and pre-stress force of anchor. The analysis result has been recorded in terms of lateral wall deflection, ground settlement, and bending moment. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Numerical Simulation of Field Vane Shear Test Using Finite Element Method(Springer Science and Business Media Deutschland GmbH, 2022) Hulagabali, A.M.; Bariker, P.; Solanki, C.H.; Dodagoudar, G.R.One of the most versatile and widely used devices for investigating the undrained shearing strength and sensitivity of soft deposits of clay is the field vane shear test. However, despite its common usage, the interpretation of the vane test has been quite often a controversial issue. Thus, this paper aims to analyze the effects of vane blade thickness and the conventional interpretation of determining shear strength from the vane shear test using the finite element method. The soil stress–strain response has been simulated using the Mohr–Coulomb constitutive model and the Hardening soil model. The sensitivity analysis of boundary conditions has been performed to select the best boundary condition among the different alternatives and to use it properly to get better output for further analysis. The results of numerical simulations have been compared with the conventional interpretation results in verifying and analyzing the performance of the numerical model. It is observed that the measured torque at failure obtained from PLAXIS 3D using the Hardening soil model fits well with the result from the theoretical calculation. However, the Mohr–Coulomb gave too large the torque at failure and the big difference between simulated and hand calculation. The measured undrained shear strengths are inversely proportional to the perimeter ratio of the vane and the same type of soil but different blade thickness, the undrained shear strength can vary significantly. The failure geometry around the blade is recognized in the plastic points, more emphasized at the top than in the middle of the device. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.