A viscoplastic damage constitutive model for concrete

Based on the static plastic damage framework forcontinuum, the dynamic-viscoplastic damage model for the nonlinear analysisof concrete structures under dynamic loading was developed in the presentpaper considering the rate-sensitivities of plastic strain and damageevolution. The Perzyna type viscoplasticity in the effective stress spacewas derived to account for the rate-sensitivity of the plastic strainevolution. The rate-dependent damage evolution was extended from the staticdamage evolution using the modified Perzyna type formulations. The uniaxialstatic damage evolution function was developed based on the parallel elementmodel. Then the multiaxial static damage evolution was established bysubstituting the energy equivalent strain into the uniaxial static damageevolution function. The stress-strain curves, the dynamic increase factorand the biaxial dynamic envelopes were simulated in the present paper. Theagreement between numerical results and experimental data indicates thevalidity of the proposed model.