| Autor: |
Roman, O. V., Zvonarev, E. V., Velyuga, L. D., Ustinova, G. P. |
| Zdroj: |
Powder Metallurgy and Metal Ceramics; October 1980, Vol. 19 Issue: 10 p669-674, 6p |
| Abstrakt: |
It is demonstrated that the Moiré method can be successfully employed for studying the stress-strain state produced in sintered porous materials by plastic working. The strained state in the stamping of impressions with a flat cylindrical punch in a porous solid is characterized by the existence of two impeded deformation zones (under the punch and at the bottom of the blank) and a nonuniform distribution of displacement rates of points in the solid, deformation rates, and deformation rate intensities Hi on a meridional section. With decreasing starting density all these phenomena become less pronounced, and at a starting density of 60% the impeded deformation zones practically vanish. The distribution of stresses on a specimen section in the initial stage of stamping an impression is characterized-by a marked nonuniformity. The nonuniformity of stress distribution diminishes with decreasing starting specimen density and on passing from upper to lower (bottom) specimen layers. Experimental contact normal and tangential stress distribution curves have enabled deforming loads to be calculated and the locations of tangential stress maxima to be determined. It has been established that tangential stresses have their maxima at the punch corners, which accounts for the increased wear of the punch edge. With increasing starting specimen density the deforming load in the stamping of an impression sharply grows. Calculated values of deforming load, Pcalc, are in good agreement with experimentally determined values, Pexp. |
| Databáze: |
Supplemental Index |
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