Damage model for normal & high strength concrete

Abstract: An anisotropic damage model capable of predicting the response of normal and high strength concretes is presented in this study. The model utilizes a concrete appropriate effective compliance matrix in constructing the constitutive equations. Three parameters alpha, beta and gamma were used in the effective compliance matrix. Alpha and beta are introduced to model the different behaviour of concrete in tension and compression while the third parameter gamma was introduced to account for volumetric change. The concept of multiple surfaces i.e. limit fracture surface, loading function surface and bounding surface, defined in strain-energy release space, is used to define the evolution of damage. After calibration for various strengths of concrete, ranging from 27.6 MPa to 120 MPa, the predictive capability of the proposed elasto-damage model for uniaxial and biaxial stress paths was investigated for uniaxial compression, biaxial compression, uniaxial tension and tension-compression. The simulative capability of the model to capture the phenomenological behaviour of concrete such as strain softening, stiffness degradation, biaxial strength envelope, volumetric dilatation, different behaviour in tension and compression, and gain in strength under increasing confinement is reflected. The predicted results correlate well with the available experimental data