The Applied mechanical and mathematical model of grinding of a solid particle by static crushing

Abstract

Now crushers are one of the most common types of crushing equipment using the principle of a mechanical method of material destruction (for example, rollers, jaws, cone crushers, etc.). To provide effective parameters of the crusher, it is necessary to take into account the correlation between the physical and mechanical characteristics of the material (sizes, shapes, strengths, fragility, uniformity, etc.) and the energy parameters of the crusher (operation and power) at the design stage. The existing theories describing the mentioned dependence and relying on different classical hypotheses allow obtaining a very approximate (inaccurate) result. Consequently, it is necessary to develop a detailed theory of crushing capable of an accurate description of the mechanical process of material destructions by working members of the crushers. Thus, the authors have developed the crushing theory as an original solution of a complex constructively nonlinear engineering and technical problem on the static contact of a spherical model of a comminuted brittle substance with absolutely rigid convex-concave surfaces of cylindrical rolls designed for coarse and medium grinding. The theory is based on the classical assumptions of the mechanics of an elastically deformable continuous medium, the fundamental analytical dependences of Hertz-Shtaerman and the Kirpichev-Kick volumetric energy hypothesis. During the quantitative assessment of the bearing capacity of the ball, we used the well-known physical and mathematical problem of Weber on the stress state of a sphere loaded by two equal forces applied at the poles, and the Kulon-Mor’s strength criterion, which describes the process of destruction of a wide class of brittle homogeneous materials. The developed theory of fragmentation has been brought to the design formulas and illustrated with a typical numerical example.