Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
Browse
11 results
Search Results
Item Influence of masonry infill on fundamental natural frequency of 2D RC frames(2010) Chethan, K.; Ramesh Babu, R.; Venkataramana, K.; Sharma, A.Reinforced Concrete (RC) framed structures with Un-Reinforced Masonry (URM) infill panels form a major portion of all the RC framed structures worldwide. The URM panels are considered as non-structural members, which is fairly good assumption under gravity loads, however, it is not the same under lateral forces. Under seismic loads, the stiffness additions due to infill panels modify the dynamic behavior of the structure significantly by altering the frequency of the structure. A research project has been taken up at Earthquake Engineering and Vibration Research Centre (EVRC), Central Power Research Institute (CPRI), Bangalore to investigate the influence of masonry infill on fundamental natural frequency of RC frames. 2D RC frames of one bay and two bay having single storey, double storey and three storeys are cast and tested for bare frame and many combinations of URM infill panels. Tri-axial shake table is used for testing. The details of the numerical analysis and experimentation carried out in the research project are brought out in this paper.Item Significance of modeling techniques in pushover analysis of RC buildings(2010) Thapa, M.; BabuNarayan, K.S.; Halemane, K.P.; Venkataramana, K.; Yaragal, S.C.; Ramesh Babu, R.; Sharma, A.; Reddy, G.R.The study presented here focuses on the effectiveness of the models adopted for the nonlinear static pushover (NSP) analysis and providing the best model that can predict the nonlinear response of RC buildings with sufficient accuracy with respect to the experimentally obtained results. NSP analysis considers material nonlinearity and is an effective tool to evaluate the performance of the structure under lateral seismic loads. However, the actual test data in order to verify the results of NSP analysis are very rare for RC structures, which are analytically sensitive to the models and procedure adopted by the analyzer. Under the present work three cases of geometric models; a) Frame with beamcolumn elements, b) Frame with beam-column elements and slabs modelled as a rigid diaphragm and c) Frame with beam-column elements and slabs modelled as shell element considering concrete as confined and unconfined were analyzed. Comparision of analytical curve with the experimental pushover curve, clearly suggests that frame modelled as confined beam-column elements and slabs modelled as a rigid diaphragm gives closer results. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Studies on concrete cylinders subjected to elevated temperatures(2010) Babu Narayan, K.S.; Anil Kumar, G.; Chandrakala, C.; Shashikumar, H.M.; Venkataramana, K.; Yaragal, S.C.; Chinnagiri Gowda, H.C.; Reddy, G.R.; Sharma, A.Concrete is a poor conductor of heat, but can suffer considerable damage when exposed to fire. Concrete in structures is likely to be exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. Unraveling the heating history of concrete is important to forensic research or to determine whether a fire exposed concrete structures and its components are still structurally sound or not. Assessment of fire damage concrete structures usually starts with visual observation of color change, cracking and spalling. On heating, a change in color from normal to pink is often observed and this is useful since it coincides with the onset of significant loss of concrete strength. This work reports the characteristics of concrete at elevated temperatures. Popular normal strength grades (M20, M25, M30, M35, M40 and M45) produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm diameter and 300mm height cylinders) to obtain more meaningful and realistic data. In the preliminary phase 150 mm diameter and 300mm height cylinders were cast, cured and tested by destructive method for gathering data on strength characteristics. Later these test samples were subjected to elevated temperatures ranging from 100°C to 800°C, in steps of 100°C with a retention period of 2 hours. After exposure, weight losses were determined and then again destructive tests were conducted to estimate the residual split tensile strength. Test results indicated that weight and strength significantly reduces with an increase in temperature. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Strength retention characteristics of concrete cubes subjected to elevated temperatures(2010) Yaragal, S.C.; Clarke, K.S.; Mahesh Babu, K.; Ashokumar, S.; Venkataramana, K.; Babu Narayan, K.S.; Chinnagiri Gowda, H.C.; Reddy, G.R.; Sharma, A.Concrete in structures is likely to be exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. The probability of its exposure to elevated temperatures is high due to natural hazards, accidents and sabotages. Therefore, the performance of concrete during and after exposure to elevated temperature is a subject of great interest to the designer. Physical changes like cracking, colour change, spalling and chemical changes like decomposition of Ca(OH)2 and the C-S-H gel take place when subjected to elevated temperatures. This work reports the characteristics of concrete at elevated temperatures. Popular normal strength grades (M20, M25, M30, M35, M40 and M45) produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm cubes) to obtain more meaningful and realistic data. In the preliminary phase 150 mm cubes were cast, cured and tested by destructive method for gathering data on strength characteristics. Later these test samples were subjected to elevated temperatures ranging from 100°C to 800°C, in steps of 100°C with a retention period of 2 hours. After exposure, weight losses were determined and then again destructive tests were conducted to estimate the residual compressive strength. Test results indicated that weight and strength significantly reduces with an increase in temperature. © 2010 CAFET-INNOVA TECHNICAL SOCIETY.Item Studies on normal strength concrete cubes subjected to elevated temperatures(2010) Yaragal, S.C.; Babu Narayan, K.S.; Venkataramana, K.; Kulkarni, K.S.; Gowda, H.C.C.; Reddy, G.R.; Sharma, A.Concrete in structures is likely to be exposed to high temperatures during fire. The probability of its exposure to elevated temperatures is high due to natural hazards, accidents and sabotages. Therefore, the performance of concrete during and after exposure to elevated temperature is a subject of great importance and interest to the designer. Popular normal strength grades of concrete produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm cubes), cured and tested by destructive method for gathering data on strength characteristics. Later, these test samples were subjected to elevated temperatures ranging from 100 C to 800 C, in steps of 100 C with a retention period of 2 hours. After exposure, weight losses and the residual compressive strength retention characteristics are studied. Test results indicated that weight and strength significantly reduces with an increase in temperature. Residual compressive strength prediction equations are proposed for normal strength concretes subjected to elevated temperatures.Item Studies on the influence of infill on dynamic characteristics of reinforced concrete frames(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Chethan, K.; Ramesh Babu, R.; Venkataramana, K.; Sharma, A.The basic investigation under dynamic loads starts with the estimation of the natural frequencies of the structure or system under consideration. This is an important parameter under dynamic analysis. Hence a detailed study has been carried out on the influence of masonry infill (MI) on fundamental natural frequency of RC frames. MI though considered as non-structural element largely affect the strength, stiffness and ductility of the framed structure during the application of lateral forces such as wind and earthquake loads. Experimental and Numerical studies are carried out on RC frames under different configurations of MI in addition to bare frames. The RC frames are designed and detailed as per the relevant Indian standard codes. A simple numerical method has been formulated to obtain the natural frequencies of RC frames with MI using FE analysis. Tri-axial shake table is used for the determination of natural frequencies experimentally. This is a part of the collaborative project between BARC, Mumbai and CPRI, Bangalore focusing on the Response evaluation of RC frames under dynamic loading. This paper consists of numerical formulation, FE analysis, Shake table tests and comparison of results. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Ageist Spider Monkey Optimization algorithm(Elsevier B.V., 2016) Sharma, A.; Sharma, A.; Panigrahi, B.K.; Kiran, D.; Kumar, R.Swarm Intelligence (SI) is quite popular in the field of numerical optimization and has enormous scope for research. A number of algorithms based on decentralized and self-organized swarm behavior of natural as well as artificial systems have been proposed and developed in last few years. Spider Monkey Optimization (SMO) algorithm, inspired by the intelligent behavior of spider monkeys, is one such recently proposed algorithm. The algorithm along with some of its variants has proved to be very successful and efficient. A spider monkey group consists of members from every age group. The agility and swiftness of the spider monkeys differ on the basis of their age groups. This paper proposes a new variant of SMO algorithm termed as Ageist Spider Monkey Optimization (ASMO) algorithm which seems more practical in biological terms and works on the basis of age difference present in spider monkey population. Experiments on different benchmark functions with different parameters and settings have been carried out and the variant with the best suited settings is proposed. This variant of SMO has enhanced the performance of its original version. Also, ASMO has performed better in comparison to some of the recent advanced algorithms. © 2016Item Modified null space strategy to solve consensus problem(University of Kuwait, 2016) Sharma, A.; Kurapati, N.G.; Jagannath, R.P.K.; Wira, P.; Lal, S.; Narasimhadhan, A.V.In the domain of multi robot systems, several applications necessitate agreement of all the individual robots at consensus/rendezvous point. Such an agreement can only be achieved by means of a control strategy. However, presence of obstacles in the navigation-environment makes the achievement of control objective floundering. This paper accentuates the failure of extant null space based control strategy to circumvent rectangular obstacles by means of mathematical proofs and extensive simulation studies. To over-come these short-comings, a modified null space based control strategy is proposed to solve the consensus problem. Proposed control strategy is tested in a complex environment consisting of rectangular and concave obstacles by means of computer simulations. Finally, a qualitative comparative analysis is presented to contrast the differences between conventional null space based strategy and the proposed modified null space strategy. © 2016, University of Kuwait. All rights reserved.Item An investigation on CRDi engine characteristic using renewable orange-peel oil(Elsevier Ltd, 2019) Bragadeshwaran, B.; Kasianantham, K.; Arumuga Perumal, D.A.; Babu, J.M.; Tiwari, A.; Sharma, A.Aiming towards discovering a solution for the imminent fossil fuel crisis, the research contributes towards the utilisation of orange peel oil as a potential alternative to mineral diesel while strictly adhering to the emission norms. The study reveals the performance, combustion and emissions characteristics obtained upon operating a 20% by volume of OPO blended with diesel, in a compression ignition engine, integrated with a common rail direct injection (CRDi) system. The fuel injection pressures were varied as 400 bar, 500 bar and 600 bar. Furthermore, two stage injection strategies were employed while varying the pilot charge quantity as 10%, 20% and 30%. Subsequently, 10% EGR was employed for the test with 30% pilot injection quantity upon realising that the respective NOx emissions were the highest for the same. All the results were compared with the test results while utilising diesel at 600 bar injection pressure. For OPO20 the brake thermal efficiency at full load was observed to be 31.37% higher and the brake specific fuel consumption 5.53% lower than that for diesel. In-cylinder pressure values recorded were almost similar to diesel corresponding to brake power. Heat release rate was significantly higher in case of orange peel oil. Additionally, it was found that smoke, unburned hydrocarbons content and carbon monoxide emission decreased by 16.30%, 27.63% and 42.28% respectively in the engine exhaust. Oxides of nitrogen were recorded to be 15.46% higher than that of diesel. © 2018 Elsevier LtdItem Quality Dimensions of Augmented Reality-based Mobile Apps for Smart-Tourism and its Impact on Customer Satisfaction & Reuse Intention(Routledge, 2023) Anand, K.; Arya, V.; Sheena, S.; Sharma, A.The COVID-19 pandemic has severely affected the tourism industry, with national lockdowns aimed at curbing the spread of the virus mandating travel restrictions and prohibiting events and gatherings. The shift to online video conferencing tools, which offer limited interactivity, has spurred the need to integrate augmented reality (AR) in various contexts, such as meetings, exhibitions, museums, and travel. This quantitative study examines visitors’ perspectives on AR-based apps in tourism. It investigates the influence of three kinds of quality determinants, such as information quality, system quality, and service quality, on visitors’ perspectives on AR apps. Their impact on visitor satisfaction ultimately triggers visitors to reuse AR-based mobile apps. The research makes a theoretical contribution to the literature on AR and the quality dimensions of mobile apps. We expect demand for AR-based apps to rapidly increase, as people continue to follow preventive measures even after COVID-19. © 2022 Informa UK Limited, trading as Taylor & Francis Group.