INVESTIGATING THE STRESS STATE OF THE BENT SINTERED WIDE STRIP
A plastic pure bending of a wide strip of sintered non-hardening material under the conditions of plane deformation is studied. The problem is solved by two simplified methods, based on the known analytical formula of radial stress. The solution of the problem of plastic pure bending of a flat strip from a continuous non-hardening material is considered. The magnitudes of the main stresses, arising in the stretching and compressing layers of the plane-deformed strip are estimated. Formulae for the radial and circumferential stresses in dimensionless quantities, as well as formulae for determining their magnitude for various materials are given. In the first case, it is assumed that by analogy with a continuous material, to determine the circumferential stress of a strip of sintered material, its yield strength, depending on the porosity of the material, can be used. For this, we use the formula for the equivalent stress in the deformation theory of the plasticity of porous materials (DTPPM). It is shown that the yield stress of porous materials is expressed through the second function of porosity. In the second case, in addition to the equivalent stress formula, the condition of the plane strain and the equation of the relation between the deformation and stresses of the DTPPM, which allow the equivalent stress to be represented through the radial and circumferential stresses, are also used. As a result, a quadratic equation is obtained with respect to the circumferential stress, the solution of which is the formula for determining the circumferential stress. To solve the numerical example, the simplest porosity functions, initial data of solid material and sintered material with 10% initial porosity are selected. An algorithm for determining the components of the stress state is developed. Numerical calculations are performed in the MathCAD software environment. On the height of the strip thickness, stress plots are constructed with and without consideration of the porosity of the material, and their analysis is carried out.