Constitutive Modeling of Concrete by Using Nonassociated Plasticity

In recent years, the theory of plasticity has been widely adopted in the constitutive modeling of plain concrete. Unfortunately, the fundamental hypothesis that forms the basis of associated plasticity does not hold for concrete in some loading conditions, so that the associated plasticity models sometimes lead to great discrepancies between predicted and measured response (Chen 1981; Vermeer and de Borst 1984; Hu and Schnobrich 1988). In order to study a nonassociated plasticity for plane stress‐state concrete under short‐term monotonic loading, an elastic strain‐hardening plastic model is derived herein. This concrete material model has been tested against the experimental results of Kupfer et al. (1969). It has been demonstrated that the results achieved using an associated flow rule are usually poor, while the predictions based on the nonassociated flow rule show very good agreement with the test data.