S.K. Kaushik

Mechanical behaviour of ferrocement composites: an experimental investigation

Abstract In-plane tension, compression and bending tests were conducted on plain mortar and ferrocement specimens with woven and welded meshes. Tension tests were also carried out on meshes. Bending tests were conducted using specimens with centre point loading. The objective of the study was to investigate the behaviour of material reinforced with varying number of mesh layers and orientations and to evolve a set of elastic and inelastic material properties. It is observed that the conventional empirical relations based on mortar crushing strength overestimate the mortar modulus. The elastic moduli obtained using the rule of mixtures compares well with the values evaluated from the tests on ferrocement specimens. The 45° orientation emerges as the weakest configuration both in terms of the Youngs modulus and ultimate stress because of the lowest volume fraction of wire mesh in the direction of loading at this orientation.

Convexity studies of two anisotropic yield criteria in principal stress space

Two anisotropic yield criteria, that employ quadratic stress functions and have been extensively used for the elastoplastic analysis of composite materials, are considered. Proposed by Hoffman and by Sun, both these criteria have been formulated using nine parameters. With appropriate choice of parameters they reduce to the well‐known isotropic von Mises criterion and the anisotropic Hill criterion. This paper investigates the convexity, which is an essential condition for any plasticity model, for these criteria in the principal stress space. In each case two orthogonal sections ‐ deviatoric and volumetric ‐ are used to study the shapes of the ensuing curves. Illustrative three‐dimensional plots are included. It is concluded that, while simple interrelationships between the parameters ensure convexity of the Hoffman criterion, conditions for the Sun criterion are quite stringent.