The elasto-plastic damage model for concrete under static loading,previously proposed,was extended to account for the concrete strain-rate through viscous regularization of the evolution of the damage variables.In ord...The elasto-plastic damage model for concrete under static loading,previously proposed,was extended to account for the concrete strain-rate through viscous regularization of the evolution of the damage variables.In order to describe the energy dissipation by the motion of the structure under dynamic loading,a damping model which only includes stiffness damp stress was proposed and incorporated into the proposed rate dependent model to consider the energy dissipation at the material scale.The proposed model was developed in ABAQUS via UMAT and was verified by the simulations of concrete specimens under both tension and compression uniaxial loading at different strain rates.The nonlinear analysis of Koyna concrete dam under earthquake motions indicates that adding stiffness damp into the constitutive model can significantly enhance the calculation efficiency of the dynamic implicit analysis for greatly improving the numerical stability of the model.Considering strain rate effect in the model can affect the displacement reflection of this structure for slightly enhancing the displacement of the top,and can improve the calculation efficiency for greatly reducing the cost time.展开更多
A theoretical and numerical study has been performed on an air film dumper attached to a plate structure. Combined with the analysis by Fox and Whittorg a damping model of the air fiim damper has been developed. A com...A theoretical and numerical study has been performed on an air film dumper attached to a plate structure. Combined with the analysis by Fox and Whittorg a damping model of the air fiim damper has been developed. A complex stiffness was introduced to represent the air pressure in the damper cavity. The stain energy and dissipated energy were integrated from the real part and imaginary part of the complex stiffness to determine the stiffness and damping. The response of the plate with the air film damper was considered by treating the air film as multiple discrete damping-stiffness elements using ANSYS.展开更多
基金Project(2006BAJ03A03)supported by the National Key Technology R&D Program during the 11th Five-Year Plan Period of China
文摘The elasto-plastic damage model for concrete under static loading,previously proposed,was extended to account for the concrete strain-rate through viscous regularization of the evolution of the damage variables.In order to describe the energy dissipation by the motion of the structure under dynamic loading,a damping model which only includes stiffness damp stress was proposed and incorporated into the proposed rate dependent model to consider the energy dissipation at the material scale.The proposed model was developed in ABAQUS via UMAT and was verified by the simulations of concrete specimens under both tension and compression uniaxial loading at different strain rates.The nonlinear analysis of Koyna concrete dam under earthquake motions indicates that adding stiffness damp into the constitutive model can significantly enhance the calculation efficiency of the dynamic implicit analysis for greatly improving the numerical stability of the model.Considering strain rate effect in the model can affect the displacement reflection of this structure for slightly enhancing the displacement of the top,and can improve the calculation efficiency for greatly reducing the cost time.
文摘A theoretical and numerical study has been performed on an air film dumper attached to a plate structure. Combined with the analysis by Fox and Whittorg a damping model of the air fiim damper has been developed. A complex stiffness was introduced to represent the air pressure in the damper cavity. The stain energy and dissipated energy were integrated from the real part and imaginary part of the complex stiffness to determine the stiffness and damping. The response of the plate with the air film damper was considered by treating the air film as multiple discrete damping-stiffness elements using ANSYS.
