Accession Number:

ADA158457

Title:

Inelastic Deformation of Metals and Structures under Dynamic and Quasi-Static Cyclic Loading

Descriptive Note:

Final technical rept.

Corporate Author:

CAIRO UNIV (EGYPT) DEPT OF MECHANICAL DESIGN AND PRODUCTION

Personal Author(s):

Report Date:

1984-05-01

Pagination or Media Count:

132.0

Abstract:

The modified version of the torsional split Hopkinson bar apparatus was further exploited to generate new data bases for OFHC copper and mild steel related to their stress strain characteristics at ambient temperature under sequential reverse loading at impact strain rates, and different large values of the constant cyclic strain amplitude. The observed response was compared with that obtained under similar but quasi-static strain rate conditions. All data were evaluated in terms of various Bauschinger effect parameters. It is shown that the common practice of using quasi-static reverse loading characteristics in the analysis of problems where impact strain rates are predominant can yield to an overly safe and non-economical design, particularly if strain rate sensitive materials are being used. As expected, the present data do not conform with the predictions of classical plasticity theories. since experimental conditions involved essentially large, high strain-rate and adiabatic deformations. Examination of the literature on advanced constitutive equations for metals seems to indicate that the theories of Bodner and associates and of Cernocky and Krempl offer the greatest promises for modeling the present data. Further in-depth studies in that direction are being recommended. Also investigated was the problem of the simple thick-walled tube subjected to steady internal pressure and cyclic thermal gradient.

Subject Categories:

  • Metallurgy and Metallography
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE