A New, General Theory of Plasticity for Structural Metal Alloys
Final rept. 14 Oct 1969-17 Jul 1974
JOHNS HOPKINS UNIV BALTIMORE MD
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A new, general theory of plasticity for structural metal alloys of steel, aluminum, and copper is presented. Based on experiment, general constitutive equations are provided in the two-dimensional domain for any arbitrary loading path, whether proportional or non-proportional. Two regions of large deformation have been found, an intermediate elastic-plastic region and a totally plastic region, the former bounded by an inner and outer yield surface. The functional relation between the generalized stress and strain is parabolic, with detailed constitutive relations given for each region of deformation. A new phenomenon of eruptive plastic deformation has been found when impact velocities are sufficiently high for the strain to reach the outer yield surface bounding the regions of plasticity. At this critical velocity the maximum strain increases from three to eight times, depending on the alloy, over that immediately below the critical value.
- Metallurgy and Metallography