A three-dimensional elastoplastic constitutive model for concrete

Abstract

Strength of concrete materials can be described by the theory of nonlinear unified strength criterion with four independent parameters. The failure surface of the strength criterion in the principal-stress space is smooth, and therefore it has continuous partial derivatives. The theory of nonlinear unified strength criterion is applied as a yield function, plastic shear strain is used as the hardening and softening parameters, and the hardening and softening laws are given by the stress-strain relationship under uniaxial compression. Then a three-dimensional elastic-plastic constitutive model for concrete is established. A user-defined material mechanical behavior (UMAT) is developed based on the finite element analysis software ABAQUS. The load resistance and the deformation capacity of a reinforced concrete column under eccentric compression are simulated using the present model. The present theoretical results are comparable to the available material-test data, and the numerical results have a good agreement with the experimental observations of the concrete column. This indicates that the developed constitutive model is capable of describing the strength and deformation behaviors, and representing the strain softening behavior of concrete under three-dimensional stress state. Furthermore, the model has high efficiency and accuracy in the numerical analysis.