DOI: 10.18503/1995-2732-2024-22-4-98-105
Abstract
The aim of the work is to establish the features of shaping a flat blank at the transition of high-strength steel sheet stamping when obtaining a part of variable curvature. In the course of the work, the components of the stress tensor were calculated, the places of possible thinning and the features of the distribution of the deformation degree were considered. Tensile tests were previously carried out to determine the mechanical properties. Reference points were assigned on the blank, at which the wall thickness of the part was estimated after the stamping transition. The stress-strain state at each point was determined through the stress state index and the Lode coefficient. During computer modeling, an area located in the bending zone of the blank (point 2) was established, in which maximum thinning occurs. The degree of deformation of εр here is 0.125, the average normal stress σ is +213 MPa. The maxima of values are localized close to the inflection point, where the curvature changes sign, this point can be considered a dangerous cross section. With the relative elongation δ = 21 % obtained in the experiments, the calculated degree of deformation εр is 0.190. As it can be seen from the obtained value, the degree of deformation exceeds the calculated value in the dangerous section. However, this comparison does not take into account the fact that the linear stress state characteristic of the tensile test of the sample may not be performed in the dangerous section. At point 2, the maximum normal stresses σrr, σφφ, σzz are positive and equal to 254, 273 and 162 MPa, the calculated stress index k is 1.37, the Lode coefficient µσ is 0.62, respectively, triaxial stretching is observed, which can lead to a decrease in plasticity and further localization of the deformation degree. Localization of the deformation degree in one area can have negative consequences during further operation.
Keywords
extraction, stress tensor, thinning, Qform software module, high-strength steel
For citation
Faifer I.N., Loginov Yu.N. Plastic Bending of a Round Sheet Blank of Variable Curvature. Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2024, vol. 22, no. 4, pp. 98-105. https://doi.org/10.18503/1995-2732-2024-22-4-98-105
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