Piecewise Linear Yield Criteria Research Articles

Kinematic-Hardening in Zinc-Alloy Tubes

The kinematic theory of strain-hardening is used to evaluate the post-yield behavior of tubular specimens subjected to axial force combined with internal pressure or torque. Prediction of yield-surface motion during strain-hardening is simplified through the use of piecewise linear yield criteria. The predicted behavior is compared with the results of experiments on tubes of Zamak-3 zinc alloy. After an initial loading beyond initial yield, the tubes were reloaded along a second stress path to subsequent yield. The observed state of stress at subsequent yield agreed rather well with the kinematic-hardening theory predictions.

A theory of linear plasticity for plane strain

A reformulation is made of the classical von Mises theory of plane strain rigid-perfect plasticity. The adoption of an anisotropic piecewise linear yield criterion results in two sets of field equations, each equivalent to the classical vibrating string equation. The development of the theory is routine. Certain properties of discontinuous stress and velocity fields are discussed, but the complete development of this aspect of the theory is not given here.