Static of Powder by Logarithmic Strain

Abstract

We established a fundamental differential equation of the statics of powder, relation between principal stress and principal strain and relation between stress and principal strain. As the deformation or the strain of powder, when it is pressed, is very large we used the logarithmic strain which is suitable in this case. Next we found a simple method to calculate the stress distribution by the aid of some experiment without solving the fundamental diff erential equation. The method is that we inserted some indexes to know the displacement of points in the powder and we found length of the principal axes of the strain ellipsoid. By the length of these axes we can calculate the stress distribution using the relation described above.