ISSN 0970-0137
Current Issue
June – July 2018 issue, Vol. 45 No. 2

45-14 Shape memory alloy based smart link for aircraft wing structure: FE modelling and experimentsA.Vasanthanathan, P. Nagaraj, K. Karthick Raja, R. Kumar Arjun and M. Rajakalai127This article emphasizes on the development of Shape Memory Alloy (SMA) based smart link for the flight control system. SMA are the candidate material for the actuation of smart structures due to its Shape Memory Effect (SME). In this paper, Nitinol® is used as an SMA which is of 55% Titanium and 45% Nickel. Nitinol® in spring form, proposed in the present paper actuates the aileron which is a primary flight control system through a smart link system. The aileron facilitates the rolling motion of an aircraft. Due to symmetry, this paper addresses the actuation of aileron in one wing. Both experiments and finite element modelling are carried out. The finite element modelling of a cylindrical portion of SMA was performed so as to numerically exhibit the SME. The finite element simulation of the aileron actuation was performed by incorporating the effect of SMA spring. The finite element analysis reveals that as the temperature exceeds the phase transformation temperature (Tp), the material regain its original shape. The finite element analysis of SME was computed using ANSYS® Mechanical APDL 17.2 environment while the aileron actuation was simulated in ANSYS® 16.0 Rigid Dynamics environment. The SMA spring are actuated by heating to its phase transformation temperature. Analytical calculations are also presented for the detection of current value to be supplied into the SMA spring. Experiments are conducted in a Glass Fabric Reinforced Plastic (GFRP) wing model and the actuation of smart link has been investigated.
45-15Study on geopolymer mortar using hydrogen peroxide as foaming agentN. Anuja, and S. Prabavathy139A new arising technology called geopolymer with zero percentage of cement has been developed in order to protect our environment from harmful CO2 emission and further to save energy in the world for future use. Several drawbacks of ordinary portland cement such as low tensile strength, unstable crack propagation and low fracture resistance have been overcome by geopolymer. Further to make geopolymer as a good thermal insulating material with adequate strength, some foaming agents are added to the geopolymer mix. Foaming agents intend to develop pores inside the specimen to make it as lightweight. In this work, hydrogen peroxide is preferred as foaming agent which is added in diluted as well as undiluted form in the range of 0.3-1.8% at an interval of 0.3% so as to find the best specimen which has low density and thermal conductivity with adequate compressive strength. From the result, it was found that the geopolymer mortar cured at 80ºC for 24 hours in hot air oven with 0.9% hydrogen peroxide in diluted form gives the best result with compressive strength and density of 4.641MPa and 1209kg/m3. It also gives low thermal conductivity of 0.141W/mK when compared to normal geopolymer mortar.
45-16Experimental and finite element analysis of tubular conveyor galleryM. Gopinath, and R. Senthil148A conveyor system is a continuous system for haulage of the bulk materials. It enables us to haul anything from corn to iron ore in a continuous flow from one end of the plant to the other, feeding and reclaiming material through the different stages of the process. The tubular conveyor galleries consist of a tube, shop fabricated using steel plates forged to the required radius and welded at the longitudinal and circumferential joint section in a staggered pattern. This paper presents details of the finite element analysis (FEA) carried out to understand the behaviour of the tubular conveyer gallery systems subjected to concentrated load due to conveyer supporting system subjected to biaxial bending. Studies carried out to obtain the optimum size of the openings that can be provided for lighting and ventilation without affecting the stability of the structure to withstand dynamic loads are explained. Details of experimental investigations carried out on the scaled down model of the tubular conveyor gallery to compare the results of FEA is also presented in this paper.
45-17Comparative studies between Indian Standard codes IS 802 (part 1/ sec 1):2015 and IS 802 (part 1/ sec 1):1995 used for overhead transmission line towersVikki K. Shah, V.R. Panchal and Bipin B. Shah155Transmission line towers are steel lattice structures and were generally analyzed and designed as per Indian Standards code IS 802 (Part 1):1995. A revised code IS 802 (Part 1/ Sec 1):2015 is introduced recently for transmission line towers with modified load combinations and material input provisions. So far no attempts have been made to compare the previous code with the revised code in terms of design, analysis efficiency and economy. The present study is aimed to compare the loading, axial forces, deflection and weight of the tower using the analysis and design procedure of previous and revised codes. Two transmission line towers of same geometry were analyzed and designed using STAAD.Pro V8i software using provisions of previous and revised codes. The conclusions drawn from the comparison shows that the axial forces at critical points as per IS 802 (Part 1/ Sec 1):2015 design is 25 to 40 %, 15 to 25% and 18 to 30% for 132kV, 400kV and 765 kV respectively less than design based on IS 802 (Part 1/ Sec 1): 1995. The difference in total weight of the tower material as per IS 802-2015 design is 6.24%, 5.92% and 5.72% for 132kV, 400kV and 765 kV respectively lesser in comparison to IS 802:1995 lesser in comparison to IS 802 (Part 1/ Sec 1): 1995 design.
45-18Improved confinement model for reinforced concrete circular bridge columns under static flexural loadingNaresh Surepally and S. Suriya Prakash,161This study presents an improved analytical approach for the analysis of Reinforced Concrete (RC) circular bridge columns by proposing a new confinement model under static loading. Three widely used confinement models are examined and improvements are suggested. It is well known that the stress-strain behaviour of confined concrete is completely different from that of plain concrete. The level of confinement depends on amount of transverse reinforcement, amount of longitudinal reinforcement and spacing of rebars and level of axial load. The influence of these parameters on the section and member level behaviour is analysed and an improved model is proposed for the analysis of RC circular bridge columns under flexure. Predictions of the analytical model are compared with the experimental data of columns tested by the author and others from PEER DATABASE over a range of parameters. The comparisons indicate a very good agreement of the predictions of the proposed model with the test data.
45-19Earthquake-response of open ground storey reinforced concrete building retrofitted with and without yield type X shaped metallic elasto-plastic damperC.K. Madheswaran, N. Gopalakrishnan, J. Prakashvel and K. Sathish Kumar178A three-storey half scale Reinforced Concrete (RC) building frame model, fitted with yielding type X-shaped metallic elasto-plastic damper at the ground floor level, is designed and fabricated to study its seismic response characteristics. Experimental studies are carried out using the 4m × 4m tri-axial shake-table facility to evaluate the seismic response of a retrofitted RC frame building with Open Ground Storey (OGS) structure using yielding type X-shaped metallic elasto-plastic dampers (also called as Added Damping and Stiffness-ADAS elements) and repairing ground storey columns using Geopolymer concrete composites. In general, earthquake loading introduces large displacements in an OGS structure, and under such large displacements, a yielding type elasto-plastic device made of X-shaped metallic dampers is expected to perform better. The supporting steel frame of ADAS element is of chevron type, serially contributing stiffness to the ADAS element. Free vibration tests on RC frame building without and with yielding type X-shaped metallic damper are carried out. The natural frequencies and mode shapes of model without and with yielding type X-shaped metallic elasto-plastic damper are obtained. The reinforced concrete building is subjected to earthquake excitations. Further, seismic responses of the structure with metallic damper are evaluated with different earthquake excitations.
45-20Mechanical behaviour of pre-stressed railway sleepers using geopolymer concreteS. Imran khan, D. Brindha and G. Panneerselvam187Geopolymer concrete can be considered as a green building technology which serves as alternatives for cement and fine aggregate by using Alkaline Activator Solutions (AAS) Fly Ash (FA) Granulated Blast Furnace Slag (GGBS) and Copper Slag (CS) in Geopolymer Concrete (GC). The High Strength Geopolymer Concrete (HSGC) M60 grade concrete was designed and used for the casting of Broad Gauge Pre-tensioned Pre-Stressed Concrete (PSC) sleepers as per Indian Railway Standard Specifications. Pre-tensioning wires of standard High Tensile Strength wire (HTS) were used with a pre-tensioning force of 50kN. Compaction was achieved through table vibrators and steam curing was adopted as per the standard manufacturing process of Indian Railways. The cured concrete sleepers were tested in the lab by stimulating the actual load transfer condones in the field called Rail Seat Centre Bottom (RSCB). Moment of Resistance (MR) and Moment of Failure (MF) of the sleeper was determined for either sides of the sleeper for a loading up to 230kN (MR) and 370kN (MF) as per the standard static bending test procedure. The test results proved that the Geopolymer concrete sleeper has high yield load and high ultimate load.
45-21Flexural behaviour of reinforced fly ash and paper sludge ash- based geopolymer concrete beamsP. Senthamilselvi, and T. Palanisamy201The Present study aims at incestications of the flexural behaviour of reinforced Fly Ash (FA) Based Geopolymer Concrete (GPC) and fly ash and Paper Sludge Ash (PSA) based geopolymer concrete beams (FA-PSA-GPC) with 10% replacement of FA by PSA. The beams were made of M35 grade concrete and cured under three curing conditions viz., Ambient Curing (AC), External Exposure Curing (EEC) and Oven Curing (OC) at 60°C. The beams were tested at 28th day by conducting two-point loading flexural test. Performance aspects such as Load Carrying Capacity (LCC), First Crack Load (FCL), load-deflection behaviour, and moment-curvature behaviour of both types of beams were studied. The load-deflection and moment-curvature behaviours of two types of beams observed from the experimental results under different curing conditions were compared and it was concluded that GPC can be produced using PSA with FA.
45-22Comparison of behaviour between rebar and stud shear connectors under monotonic loadingB. Saravanakumar, and R. Thenmozhi210In composite beams, shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface. The shear connectors also prevent relative displacement of concrete and steel elements at their interface and ensure composite action of the beam. Presently, the stud is the most widely used shear connector in composite constructions. However, the rebar can be used as a shear connector according to various international codes considering the fact that it can be fabricated to the required shape along with the reinforcement cage in the slab. This paper presents an experimental study of the behaviour of rebar shear connectors embedded in composite beam under monotonic load. Two different (8mm and 10mm) diameter rebar connectors of four different forms such as open link, closed stirrups, circular and rectangular spiral were used as shear connectors. Modified push-out tests were conducted to assess the ultimate strength, elastic stiffness, load-slip characteristics and failure pattern of the rebar shear connectors and the same are compared with conventional stud shear connectors. Rebar shear connector with circular spiral shows higher ultimate strength and superior ductile behaviour compared to conventional stud shear connector.
45-T1Parametric study on seismic behaviour of slab-column junctions in flat slab system subjected to punching shearVijaya Kumar Kandi, Lute Venkat, and G. Papa Rao221-
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