Dynamic Constitutive Model Of Concrete Based On The Two Shear Unified Strength Theory

Concrete structures are often subjected to dynamic loads such as earthquake, impact and blast. Now,for the earthquake resistant design and calculation of the key factor-concrete dynamic characteristics of the study has become the recognized problems in a dynamic structural analysis. Research results show that,concrete dynamic characteristics are affected by more of factors. Under the dynamic loads concrete materials show a strong strain rate sensitive effect, its strength and flexibility modulus increase more under great strain rate. So, concrete dynamic constitutive relation study has important theoretical significance and value of projects.Based on the viscoplastic theory of Perzyna and considering the influence of strain rate on initial elastic modulus, elastic-viscoplastic dynamic constitutive model for concrete was formulated. Through applying the viscoplastic theory of Perzyna to the dynamic stress analysis of concrete in plain stress state, using the yield criterion of the two shear unified strength theory, the elastic-viscoplastic dynamic constitutive model for concrete in plain stress state under uniaxial loading was derived.Through this research, the following main conclusions of this paper:â‘ Main influencing factor on dynamic response of concrete is the strengthening effect of strain rate.â‘¡The viscoplastic theory of Perzyna can be applied to characterize the dynamic behavior of concrete. The elastic-viscoplastic dynamic constitutive model for concrete considering of changing in the initial elastic modulus under uniaxial loading in the paper is better meeting the test data.â‘¢The plane stress state of the concrete elastic-viscoplastic dynamic constitutive model has a broad applicability, the simplification results are in good agreement with test datas.