粗骨料超高性能混凝土疲劳损伤本构模型OA北大核心CSTPCD

The fatigue damage constitutive relation of ultra-high performance concrete is an important basis for the nonlinear fatigue analysis of its structural responses.In this study,an elastoplastic fatigue damage model of ultra-high performance concrete containing coarse aggregate(UHPC-CA)was developed based on continuum damage mechanics and elastoplastic theory.The fatigue damage criterion was established according to the loading/unloading irreversibility concept.As per previous test results,the fatigue damage development process of UHPC-CA,as well as the fatigue damage evolution rule considering coarse aggregate content and steel fiber characteristic parameters,were analyzed.The development of plastic deformation was determined by employing an empirical plastic model.The proposed model was verified upon the numerical implementation using a user-defined UMAT.The results show that the proposed model has broad applicability and can accurately predict the fatigue behaviors of UHPC under uniaxial compressive fatigue loading,uniaxial tensile fatigue loading,and conventional triaxial compressive fatigue loading.The research results can provide a theoretical basis for the anti-fatigue design and performance control of UHPC-CA structures.