Viscoplastic Damage-Softening Constitutive Model for Concrete Subjected to Uniaxial Dynamic Compression
【摘要】：A new viscoplastic damage-softening constitutive model is presented. It is developed by integrating a Bodner-Partom viscoplastic model with a newdamage evolution equation. A set of ordinary differential equations( ODEs) is formulated,and a Runge-Kutta integral method is used to get stress-strain curves given by the model. Also,stress-strain curves of a wide range of strain-rates for concrete were obtained by split Hopkinson pressure bar( SHPB) tests. By fitting the integral stressstrain curves to the experimental ones with the least square optimization method,we determined the material parameters in our model. Some properties of the newmodel,such as strain-rate sensitivity,damage evolution characteristics,strain-rate jump effects and unloading feature,are explored.These results showthat our new model can describe dynamic behaviors of concrete very well,and our integrating-fitting-optimizing method to get material parameters is valid.