An investigation of mechanical and rheological properties of wheat grains

For the purposes of understanding the way in which wheat grains are able to withstand forces imposed during handling and processing, it is necessary to have some knowledge of their load-deformation behaviour. For light load conditions it is shown that the grain stresses can be analysed on the basis of elasticity theory, principally employing the Hertz stress analysis. As the loads are increased up to the point of failure, the stress distribution is rather complex and difficult to analyse theoretically. However, it is demonstrated that, with the aid of photoelastic and numerical techniques, it is possible to obtain quantitative results which show the pattern of the stress distribution within a cross-section of grain.