J. Rajasankar

Cumulative damage function model for prediction of uniform corrosion rate of metals in atmospheric corrosive environment

Abstract The main focus of the paper is on the development of a unified analytical model for predicting the rate of uniform corrosion for commonly used engineering metals exposed to the atmosphere. A cumulative damage function model is proposed on the presumption that the corrosion is primarily due to the presence of critical corrosive agents in the atmosphere. The model incorporates sensitivity factors to account for the corrosion sensitivity of the metal with respect to the critical corrosive agents and the presence of other corrosive agents. Predictions of the uniform corrosion rate of metallic structures made of iron, mild steel, carbon steel, and zinc are presented. Results predicted using the model are compared with the values expected for mild steel using the data available in the Corrosion Map of India.

Nonlinear analysis of RC shell structures using multilevel modelling techniques

Purpose – The purpose of this paper is to present integrated methodologies based on multilevel modelling concepts for finite element analysis (FEA) of reinforced concrete (RC) shell structures, with specific reference to account for the nonlinear behaviour of cracked concrete and the other associated features.Design/methodology/approach – Geometric representation of the shell is enabled through multiple concrete layers. Composite characteristic of concrete is accounted by assigning different material properties to the layers. Steel reinforcement is smeared into selected concrete layers according to its position in the RC shell. The integrated model concurrently accounts for nonlinear effects due to tensile cracking, bond slip and nonlinear stress‐strain relation of concrete in compression. Smeared crack model having crack rotation capability is used to include the influence of tensile cracking of concrete. Propagation and change in direction of crack along thickness of shell with increase in load and defo...

Probabilistic modelling of fatigue crack initiation from pits and pit clusters in aluminium alloys

Abstract A numerical model of crack initiation under high cycle fatigue loading from pits is investigated in this paper. A probability based pit growth model, which takes into account the influence of mechanical cyclic load and particle clusters present in alloys, is used for investigations. Critical pit sizes, calculated using linear elastic fracture mechanics principles, are used to determine the probability of crack initiation for different conditions. The results are critically compared to extract an insight on the parameters that control the pit growth behaviour and thereby the fatigue crack initiation.

Response Simulation of a Micro Reinforced Concrete Target Under Ballistic Impact

The response of concrete structures subjected to impact loading has received extensive attention in both civil and military applications. Research on improving the shock resistance of concrete has led to the development of cementitious composites. Micro Reinforced Concrete (MRC), a type of cementitious composite, is a concrete matrix embedded with multilayered steel wire meshes. This paper presents 3D hydrocode simulations of MRC panels subjected to impact under a ballistic range. A finite element model based on Lagrange formulation is used to represent both a 300 mm × 300 mm × 100 mm target with 30 layers of wire mesh and a 5.56 × 45 mm projectile in simulations. Penetration depth and damage patterns of the MRC mesh cement composite panel are numerically compared with those of the field experiment. The results show a relatively good agreement.