Dislocation Dynamics and the Formulation of Constitutive Equations for Rate-Dependent Plastic Flow in Metals
Final technical rept. Jan 1969-Sep 1970
SYSTEMS SCIENCE AND SOFTWARE LA JOLLA CA
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A rate-dependent constitutive model is developed which describes a broad spectrum of elastic-plastic response in isotropic metals, ranging from quasi-static behavior through the thermally activated intermediate strain rate regime, up to the high strain rate region where phonon viscosity and relativistic effects appear to control the flow process. Upon reverse straining from a plastically prestrained state, the constitutive model exhibits a rate- dependent Bauschinger effect. An attempt has been made to utilize, wherever possible, current knowledge in the theory of dislocation dynamics in formulating the constitutive model. In most cases, only simple models of governing deformation mechanisms can be constructed and, even to accomplish this, considerable speculation sis required. Where dislocation theory is unable to provide guidance in defining and characterizing a particular mechanism, a phenomenological approach has been followed. The advanced constitutive model developed here has been incorporated into the one-dimensional, finite-difference RIP code. The application of this model to 6061-T6 aluminum is described.
- Metallurgy and Metallography
- Solid State Physics
- Unmanned Spacecraft