K.R.Y. Simha

Rotating anisotropic disc of uniform strength

A procedure to design a constant thickness composite disc of uniform strength by radially tailoring the anisotropic elastic constants is proposed. A special case of an isotropic disc with radially varying modulus is also examined. Analytical results are also compared with FEM calculations for two cases of radially varying anisotropy and for an isotropic disc with variable modulus

Stress concentration around irregular holes using complex variable method

Engineering materials are vulnerable targets for damage by chemical agents. This results in various types of irregular cavities which may subsequently change their shape under the combined action of loads and chemical attack. Such shape evolutions are subject to certain constraints. This paper explores the evolution in stresses as a result of an evolution in the shape of an isolated irregular hole in an infinite elastic plate subjected to remote uniform stress. The constraint employed here is a fixed area for the irregular hole with variable perimeter as a result of the evolution. Increase in perimeter implies decrease in strain energy on account of increased surface energy. Such phenomena could also occur in polymeric sheets on account of viscoelasticity even in the absence of chemical agents. This paper presents the evolution in boundary stresses as the cavity evolves to take different shapes. Complex variable methods are developed to tackle three cases of remote loading: (a) hydrostatic tension, (b) uniaxial tension, and (c) pure shear state. Of the above three cases, the first case of hydrostatic loading leads to a remarkably simple result for the boundary stress as shown in this paper. The last case is obtained by superposing a uniaxial tension and uniaxial compression along orthogonal directions.

Interface crack around circular inclusion: SIF, kinking, debonding energetics

The problem of an interfacial arc crack around a circular elastic inclusion embedded in an elastic matrix is examined. A general approach for generating uniform/non-uniform stress fields inside a test region through remotely applied point loads is demonstrated. The effects of stress gradient, arc crack angle, and elastic mismatch are discussed. Interfacial arc crack kinking is examined using the maximum tensile stress criterion only for such cases wherein the crack is open. Finally, the energetics of inclusion debonding is addressed for the specific case of hydrostatic loading.

Singularity in rotating orthotropic discs and shells

A unified formulation for studying stresses in rotating polarly orthotropic discs, shallow shells and conical shells is presented. The main focus of this paper is on the examination of singularities when tangential modulus of elasticity

Two Degrees of Freedom Modeling of Precracked Beams under Impact

(E_{\theta})

Re-examination of crack opening model of interface fracture

is smaller than the radial modulus

Applied Impact Mechanics

(E_r)

Analytical and Experimental Evaluation of Coldworking Process for Strain Hardening Materials

. The order of the singularity is extracted by expressing the solutions in terms of modified bessel function with complex argument. The order of the singularity is shown to be

Variable density approach for rotating shallow shell of variable thickness

(\sqrt{E_{\theta}/{E_r-1}})

Characterization of friction at three contact pairs by photoelastic isotropic point (IP)

in all the three cases studied here. There is no singularity present when