Abstract
Apparent internal friction factors of powders have been evaluated under various test conditions by a direct shear tester providing the following four sets of shearing stress-normal stress diagram, and compared with each others; (i) maximum shearing stress (τx, max)—applied normal stress (σz, w), (ii) steady shearing stress (τx, s)—σz, w, (iii) τx, max—actual normal stress (σz, m—measured directly by three pressure sensors in the vicinity of the shearing plane and averaged), and (iv) τx, s—σz, m diagrams. Among these diagrams, the τx, s—σz, m relation gives the internal friction factor which is fairly independent of the test conditions and can be arranged in the order of Carr's flowability index for respective powders.
