抄録
The mechanical properties of a powder are determined from the yield locus. The yield locus is often determined by approximating the results of shear tests by Coulomb equation, or by Warren-Spring equation. Meanwhile, the yield characteristics of a powder are expressed by Roscoe condition diagram. In this diagram, the yield locus appears orthogonal to the normal stress axis at both ends. However, yield locus approximated by the Coulomb and Warren-Spring equations is not orthogonal to the normal stress axis at both ends. So, the abovementioned mechanical properties obtained from the yield locus are likely to be affected by the approximate expression of the yield locus.
In this paper, I propose an approximation equation for a yield locus which expresses both the shape of yield locus in Roscoe condition diagrams and the experimental results. Then, these yield loci obtained by our equation, Coulomb and Warren-Spring equations are used to determine the mechanical and flow properties of powder beds. These values are compared with each other in order to discuss the effect of an approximation equation on mechanical properties.
