The elastic properties of micrometer-sized hollow colloidal particles obtained by emulsion templating are probed by nanoindentation measurements in which point forces are applied to solvent-filled particles supported on a flat substrate. We show that the shells respond linearly up to forces of 7-21 nN, where the indentation becomes of the order of the shell thickness (20-40 nm). In the linear r...

We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells are subject to a wrinkling instability. We study wrinkling in depth, presenting scaling laws for the critical indentation at which wrinkling occurs and the nu...

In the present research, a unified formulation for free vibration analysis of the bidirectional functionally graded conical and cylindrical shells and annular plates on elastic foundations is developed. To cover more individual cases and optimally tailored material properties, the material properties are assumed to vary in both the meridian/radial and transverse directions. The shell/plate is a...

Keywords: Incompressible Initial stress Anisotropic S-wave Gravity field a b s t r a c t In this paper, propagation of shear waves in a non-homogeneous anisotropic incompress-ible, gravity field and initially stressed medium is studied. Analytical analysis reveals that the velocity of propagation of the shear waves depends upon the direction of propagation, the anisotropy, gravity field, non-ho...

Buckling of cylindrical sandwich shells subject to axial compression is addressed for shells having foamed metal cores. Optimal face sheet thickness, core thickness and core density are obtained which minimize the weight of a geometrically perfect shell with a speci®ed load carrying capacity. Constraints imposed by wrinkling and yielding of the face sheets and yielding of the core are all consi...

INTRODUCTION Computational modelling in orthopaedic biomechanics often uses continuum homogenised finite element models of the bone which require accurate definitions of its elastic properties. In this study the variation of the orthotropic elastic constants of cortical bone from the female anterior femoral midshaft were evaulated. Micro-finite-element (μFE) analysis of bone samples from 27 fem...

We derive an expression relating the axial load, the indentation depth, and the elastic constants of an orthotropic material, and simplify it to that for a cubic material (e.g., an FCC single crystal). We use this formula and results of three virtual (i.e., numerical) indentation tests on the same specimen oriented differently to find values of the elastic moduli, and show that they agree well ...