Ananthalakshmi K. Iyer¹, A. Rama Chra Murthy², Smitha Gopinath², Nagesh R. Iyer³

CMC-Computers, Materials & Continua, Vol.42, No.3, pp. 227-244, 2014, DOI:10.3970/cmc.2014.042.227

Abstract A non-linear fracture mechanics based approach is proposed to depict a typical fracture mechanism from initiation to growth, eventually leading to failure. This concept is developed for a lightly reinforced beam in flexure. The proposed model integrates the existing methodology of a Stress Intensity Factor equilibrium equation with the bridging forces developed in concrete cover and rebar. The model and solution algorithm outlined presents an elaborate understanding of the mechanism involved and is significant in predicting the behaviour of flexural members. The analysis is performed using MATLAB programming. The proposed approach ensures a maximum tolerable More >

Smitha Gopinath^1,2, J. Rajasankar¹, Nagesh R.Iyer¹, A.Rama Chandra Murthy¹

CMC-Computers, Materials & Continua, Vol.33, No.1, pp. 87-110, 2013, DOI:10.3970/cmc.2013.033.087

Abstract An integrated model is proposed to describe tension stiffening in reinforced concrete (RC) flexural members that are undergoing uniform corrosion of reinforcement. The tension stiffening model is taken as base to incorporate the effects of reinforcement corrosion. The model is developed in two steps. In the first step, tension stiffening of concrete is modelled using an exponential stress-strain curve defined as function of a decay parameter. Modular ratio and reinforcement ratio are considered in the definition of the decay parameter. In the second step, the effects of uniform corrosion of reinforcement are integrated with the… More >

Smitha Gopinath¹, C.K. Madheswaran¹, A. Rama Ch,ra Murthy¹, Nagesh. R. Iyer², Barkavi.T³

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.2, pp. 151-172, 2013, DOI:10.3970/cmes.2013.092.151

Abstract This paper presents the details of experimental and numerical investigations performed on fabric reinforced concrete (FABcrete) panels under impact loading. Experimental investigations have been carried out using drop weight impact on a square FABcrete panel to study the damage, failure mode and acceleration. The drop weight of 20 kg is used for the study and drop heights have been varied as 100mm, 200mm and 300mm. Numerical simulation of the drop weight impact tests on FABcrete panels have been carried out and observed that there is a good correlation between experimental and numerical predictions. It is More >

A. Ramachandra Murthy¹ , G.S. Palani¹ , Nagesh R. Iyer¹ , Smitha Gopinath¹ and V. Ramesh Kumar¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.5, pp. 409-434, 2012, DOI:10.3970/cmes.2012.086.409

Abstract This paper presents the details of projectile impact on reinforced concrete structural components. Nonlinear explicit transient dynamic analysis has been carried out by using finite element method. Concrete damage model has been employed to represent the nonlinear behaviour of target under impact load. Various methods of modeling of reinforcement have been explained. A brief note on equation of state for concrete, contact algorithms and nonlinear explicit transient dynamic analysis has been given. Numerical studies have been carried out to compute the response of concrete target due to impact of projectile. The computed penetration depth have More >

A Rama Chandra Murthy¹, Smitha Gopinath^1,2, Ashish Shrivastav¹, G. S. Palani¹, Nagesh R. Iyer¹

CMC-Computers, Materials & Continua, Vol.25, No.1, pp. 1-18, 2011, DOI:10.3970/cmc.2011.025.001

Abstract This paper presents methodologies for crack growth study and fatigue remaining life prediction of reinforced concrete structural components accounting for the corrosion effects. Stress intensity factor (SIF) has been computed by using the principle of superposition. At each incremental crack length, net SIF has been computed as the difference of SIF of plain concrete and reinforcement. The behaviour of reinforcement has been considered as elasto-plastic. Uniform corrosion rate has been assumed in the modeling. Corrosion effect has been accounted in the form of reduction in the diameter and modulus of elasticity of steel. Numerical studies More >

Smitha Gopinath^1,2, A. Ramach,ra Murthy¹, Nagesh R. Iyer¹

CMC-Computers, Materials & Continua, Vol.22, No.1, pp. 55-72, 2011, DOI:10.3970/cmc.2011.022.055

Abstract This paper presents the mathematical modeling techniques for nonlinear finite element analysis of RC structure to incorporate uniform corrosion effects. Effect of corrosion has been simulated as reduction in effective cross-sectional area of reinforcing bar, reduction in bonding phenomena and as reduction in material properties of reinforcing bar such as yield strength and elastic modulus. Appropriate constitutive laws for (i) corroded rebar elements and (ii) bond slip with corroded bar have been described. Procedure has been outlined to determine the global damage indicator by secant stiffness based approach. A corroded RC beam has been analysed More >

Smitha Gopinath¹, J. Rajasankar^1,2, Nagesh R. Iyer¹, T. S. Krishnamoorthy¹, B.H.Bharatkumar¹, N. Lakshmanan¹

Structural Durability & Health Monitoring, Vol.5, No.4, pp. 311-336, 2009, DOI:10.3970/sdhm.2009.005.311

Abstract In this paper, a two-phase strain-based constitutive model is proposed for concrete under tension. First phase deals with modelling uncracked concrete while the behaviour of concrete in cracked condition is modelled in second phase with appropriate theoretical support. A bilinear tension softening curve of concrete defined in crack width-stress space is taken as the basis to propose the model. Smeared representation of reinforcement and cracks along with multi-layered geometry definition of reinforced concrete (RC) structures is used to implement the model. Through this, it is shown that change in the orientation of tensile cracks with… More >

Hisham Abdel-Fattah¹, Sameer Hamoush²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.4, pp. 111-112, 2009, DOI:10.3970/icces.2009.011.111

Abstract This paper develops Fiber Reinforced Plastic (FRP) Composites retrofit systems to enhance the structural performance of deficient reinforced concrete beams. The paper highlights the design of the different FRP systems and then, systems with promising results are used to upgrade deficient beams. Structural evaluation for retrofitted beams is performed to evaluate the ductility and strength performance. This study mainly focuses on the uses of Glass Fiber Reinforced Plastics (GFRP), Carbon Fiber Reinforced Plastics (CFRP) and hybrid reinforced plastics that use a mixture of carbon and glass fibers. As part of the design of the FRP… More >

Gang Lin¹, Yinghua Liu^1,2, Zhihai Xiang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.3, pp. 217-252, 2009, DOI:10.3970/cmes.2009.047.217

Abstract Deterioration of reinforced concrete (RC) structures due to chloride ingress followed by reinforcement corrosion is a serious problem all over the world, therefore prediction of chloride profiles is a key element in evaluating durability and integrity of RC structures exposed to chloride environment. In the present paper, an integrated finite element-based computational framework is developed for predicting service life of RC structures exposed to chloride environment, which takes environment temperature and humidity fluctuations, diffusion and convection, chloride binding, as well as the decay of durability of structures caused by coupled deterioration processes into account. The… More >

Chun-Ying. Wu¹, R. Al-Khoury², C. Kasbergen², Xue-Yan. Liu², A. Scarpas²

CMES-Computer Modeling in Engineering & Sciences, Vol.17, No.3, pp. 163-172, 2007, DOI:10.3970/cmes.2007.017.163

Abstract 3D spectral element method in the article is presented to predict the pavement layer modules using field measurement of Falling Weight Deflectometer (FWD). To improve the computational efficiency of the layer-condition assessment, one type of spectral element is proposed to develop the dynamic analysis of 3D multi-layered system subjected to an impulsive load. Each layer in structure is simulated as two-noded layer spectral element or one-noded spectral element in frequency domain. In order to identify the parameters of layered structures, a nonlinear optimization method called Powell hybrid algorithm is employed. The optimization procedure is performed More >