Content deleted Content added
m Typo fixing, typos fixed: i.e, → i.e., using AWB |
|||
Line 60:
Hence, both the normal to the yield surface and the plastic strain tensor are perpendicular to the stress tensor and must have the same direction.
For a [[strain hardening|work hardening]] material, the yield surface can expand with increasing stress. We assume Drucker's second stability postulate which states that for an infinitesimal stress cycle this plastic work is positive, i.e.,
:<math>
d\boldsymbol{\sigma}: d\boldsymbol{\varepsilon}_p \ge 0 \,.
| |||