An Improved Method for Estimation of Elastic Lateral Stiffness of Brick Masonry Shear Walls with Openings

S. R. Balasubramanian,K. Balaji Rao,Dhiman Basu,M. B. Anoop,C. V. Vaidyanathan 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.2

From a review of literature, it is found that while few methods are proposed by various researchers for estimation of lateral stiffness of brick masonry walls with openings, these methods are suitable for strong spandrel-weak pier condition. For weak spandrel-strong pier condition, these methods over estimate the stiffness. An improved method for estimation of stiffness of brick masonry shear walls with opening is presented in this paper. For the weak spandrel-strong pier condition, they overestimate the stiffness of the wall. The proposed method is applicable to both strong spandrel-weak pier and weak spandrel-strong pier conditions. It has been observed that the results of the proposed method are generally in good agreement with the results of finite element analysis and experimental results and are better than the other methods available in literature.

Comparative Evaluation of the Abrasive Slurry Wear Behavior of Alloy Surfaces Produced by a Plasma Transferred Arc Hardfacing Process

C. S. Ramachandran,V. Balasubramanian,R. Varahamoorthy 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.2

Abrasive slurry wear is generally defined as a mechanical interaction in which the material becomes lost in a surface that is in contact with moving particles, such as laden liquid. Slurry wear abrasion occurs in extruders, slurry pumps, and pipes that carry the slurry of minerals and ores in mineral processing industries. The life of the components used under slurry abrasion conditions is governed by the process parameters,the properties of the abrasive particles in the slurry, and the material properties. This paper analyses in detail the effects of operating variables, such as abrasive particle size, slurry concentration, speed of rotation, and slurry bath temperature, on the abrasive slurry wear behavior of a iron based alloy (stainless steel), cobalt based alloy (stellite), and nickel based alloy (colmonoy) surfaces produced by a Plasma Transferred Arc (PTA) hardfacing process. Of the four variables considered in this investigation, it was found that the slurry concentration had a predominant effect on the wear rate of hardfaced surfaces compared to the other variables. Microstructural analyses of the worned surfaces were carried out using SEM. Both the experimental and mathematical investigations showed that the wear resistance of an iron based alloy was 4 times better than the base metal. Similarly, the cobalt based alloy exhibited a 3 times higher wear resistance while the nickel based alloy showed a 2 times higher wear resistance compared to the base metal (carbon steel).

Influences of Process Parameters on Tensile Strength of Friction Stir Welded Cast A319 Aluminium Alloy Joints

M. Jayaraman,R. Sivasubramanian,S. Babu,V. Balasubramanian 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.2

Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking. Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at four levels. The quality of weld zone was analyzed using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone microstructure. The joint fabricated with a 1200 rpm tool rotation speed, 40 mm/min welding speed, and 4 kN axial force showed superior tensile strength compared with the other joints. Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking. Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at four levels. The quality of weld zone was analyzed using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone microstructure. The joint fabricated with a 1200 rpm tool rotation speed, 40 mm/min welding speed, and 4 kN axial force showed superior tensile strength compared with the other joints.

Asymptotic Behavior of Solutions of a Class of Second Order Quasilinear Difference Equations

E. Thandapani,S. Pandian,R. K. Balasubramanian 경북대학교 자연과학대학 수학과 2004 Kyungpook mathematical journal Vol.44 No.2

In this paper, we study asymptotic behavior of solutions of a class of second order quasilinear difference equations. All proper solutions are classfied into four types by means of their asymptotic behavior. Necessary and / or suffcient conditions are given for such equations to have solutions of each of the four types.

Preparation of Biomass Based Carbon for Electrochemical Energy Storage Application

Harshini Priyaa, V.S.,Saravanathamizhan, R.,Balasubramanian, N. The Korean Electrochemical Society 2019 Journal of electrochemical science and technology Vol.10 No.2

The activated carbon materials were prepared from waste biomass by ultrasonic assisted chemical activation method (UCA), ultrasonic assisted physical activation method (UPA) and Manganese nitrogen doped carbon (Mn/N-C). The XRD result shows the turbostatic (fully disordered) structure. The cyclic voltammetry test was done at 50 mV/s using 1M sodium sulfate and the values of specific capacitance were found to be 93, 100 and 115 F/g for UCA, UPA and Mn/N-C respectively. The power density values for the samples UCA, UPA and Mn/N-C were found to be 46.04, 87.97 and 131.42 W/kg respectively. The electrochemical impedance spectroscopy was done at low frequency between 1 to 10 kHz. The Nyquist plot gives the resistant characteristics of the materials due to diffusional resistance at the electrode-electrolyte interface. The Energy Dispersive X-Ray Spectroscopyanalysis (EDAX) analysis showed that the percentage doping of nitrogen and manganese were 3.53 wt% and 9.44 wt% respectively. It is observed from the experiment Mn/N-C doped carbon show good physical and electrochemical properties.

Predicting the Dilution of Plasma Transferred Arc Hardfacing of Stellite on Carbon Steel Using Response Surface Methodology

( A. K. Lakshminarayanan ),( V. Balasubramanian ),( R. Varahamoorthy ),( S. Babu ) 대한금속재료학회 ( 구 대한금속학회 ) 2008 METALS AND MATERIALS International Vol.14 No.6

Control of dilution is important in hardfacing, where low dilution is typically desirable. At present, most fabrication industries use shielded metal arc welding, gas metal arc welding, gas tungsten arc welding and submerged arc welding processes for hardfacing purposes. In these processes, the percentage of the dilution level is higher, ranging between 10 % and 30 %. In Plasma Transferred Arc (PTA) hardfacing, a solidified metallurgical bond between the deposit and the substrate is obtained with minimum dilution (less than 10 %). This paper highlights the application of response surface methodology to predict and optimize the percentage of the dilution of a cobalt-based hardfaced surface produced by the PTA process. Experiments were conducted based on a fully replicable five-factor, five-level central composite rotatable design and a mathematical model was developed using response surface methodology. Furthermore, the response surface methodology was used to optimize the process parameters that yield the lowest percentage of dilution.

Modelling of strains in reinforced concrete flexural members using alpha-stable distribution

K. Balaji Rao,M. B. Anoop,K. Kesavan,S. R. Balasubramanian,K. Ravisankar,Nagesh R. Iyer 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.11 No.5

Large fluctuations in surface strain at the level of steel are expected in reinforced concrete flexural members at a given stage of loading due to the emergent structure (emergence of new crack patterns). This has been identified in developing deterministic constitutive models for finite element applications in Ibrahimbegovic et al. (2010). The aim of this paper is to identify a suitable probability distribution for describing the large deviations at far from equilibrium points due to emergent structures, based on phenomenological, thermodynamic and statistical considerations. Motivated by the investigations reported by Prigogine (1978) and Rubi (2008), distributions with heavy tails (namely, alpha-stable distributions) are proposed for modeling the variations in strain in reinforced concrete flexural members to account for the large fluctuations. The applicability of alpha-stable distributions at or in the neighborhood of far from equilibrium points is examined based on the results obtained from carefully planned experimental investigations, on seven reinforced concrete flexural members. It is found that alpha-stable distribution performs better than normal distribution for modeling the observed surface strains in reinforced concrete flexural members at these points.