Raju Sethuraman

Semi-elliptical surface cracks subjected to cyclic bending loads are of importance to nuclear industry. In this study, the results of experimental studies on a SS316L(N) plate subjected to bending loads, at room temperature are presented. Plates with semi-elliptical surface cracks were experimentally subjected to cyclic bending loads. The crack profiles were monitored at regular intervals using a crack depth gauge. The crack profiles were used to characterize crack propagation laws along both surface and depth direction. The crack propagation profiles were simulated using available empirical equations and compared with the experimental results. The validity of the empirical equations for prediction of crack propagation was established. The experimental observations and empirical simulations indicate that the cracks tend to propagate more in the surface direction as compared to the depth direction, for the chosen loading and geometric conditions. The observed nature of crack propagation is significant for the design of the components for Leak Before Break (LBB).

The study of vibration behaviour of cracked system is an important area of research. In the present work we present a mathematical model to study the effect of inclination, location and size of the crack on the vibrational behavior of beam with different boundary conditions. The model is based on the assumption that the equivalent flexible rigidity of the cracked beam can be written in terms of the flexible rigidity of the uncracked beam, based on the energy approach as proposed by earlier researchers. In the present work the Differential Quadrature Method (DQM) is used to solve equation of motion derived by using Euler's beam theory. The primary interest of the paper is to study the effect of inclined crack on natural frequency. We have also studied the beam vibration with and without vertical edge crack as a special case to validate the model. The DQM results for the natural frequencies of cracked beams agree well with other literature values and ANSYS solutions.

This paper deals with the dynamic characteristics of hemispherical sandwich shells with electro-rheological (ER) fluid core under clamped free and clamped clamped conditions. The free vibration and damping analysis is carried out by using the semi-analytical finite element method. Three noded line elements with seven degree of freedom per node are used in meridional direction and Fourier series is assumed in circumferential direction. There are two types of electro-rheological fluid cores used in the present study. The damping variation of hemispherical sandwich shell for different radius to thickness (R/t) ratio and core to facing thickness ratio (tc/tf) are carried out. The variation of damping properties of ER fluid with electric field is also investigated.

In this paper, linear buckling and vibration behaviour of multiphase magnetoelectroelastic (MEE) cantilever beam is analysed using finite element approach. The constitutive equations for the magnetoelectroelastic materials are used to derive finite element equations involving the mechanical, electrical and magnetic fields for the structure. The multiphase magnetoelectroelastic beam consists of piezomagnetic (CoFe2O4) matrix reinforced by piezoelectric (BaTiO3) material for different volume fraction. The influences of material constants on critical buckling load were studied. Numerical study on multiphase magnetoelectroelastic beam with different volume fraction was attempted.