Tribomechanical analysis of interlayer shear and surface crack nucleation processes in compacted disperse materials

The effect of the internal (interparticle) and external friction on the limiting state generation has been analyzed in terms of the shear-induced failure criterion of the surface layers in the compacted disperse materials. The proposed design scheme based on the Mohr-Coulomb combined diagram has made it possible to develop an original method and derive analytic dependences for determining the normal and tangential stresses in the interlayer shear sites along with the orientation angles of these sites. It has been shown that, with increasing coefficient of external friction, the pressure in the interlayer shear sites reduces until tensile stresses are generated. This is accompanied by the nucleation of the crack at a right angle close to the side surface perpendicular of the formed item.