The Three Points Bend Numerical Test Study On The Effect Of Micro-structure Of Concrete Beam On The Static And Dynamic Bearing Capacity Of Material

In this paper, with calculation micro-mechanics method, mass concrete was taken as three-phase composites, which consists of mortar matrix, aggregate and bond between matrix and aggregate. with finite element method, based on the secondary development of Ansys, the author introduced the Conduplicate-line damage evolvement model, then the simulation of static and dynamic mechanics performance of the three-graded concrete was studied by means of the software of Ansys,The author calculated the aggregate number of three-graded concrete,According to the calculation formula of the aggregate number,the random position coordinate of aggregate was generated by Monte Carlo method, then editing the subprogram using the Fortran program, this subprogram can make batch processing on the position coordinate of aggregate that generated before, then converted it to the command flow which can be recognize by Ansys. Furthermore, the random aggregate model was established. The mesh of finite element was generated and simulated the fabric of concrete. The different material property of elements was identified and assigned. The performance of complexity and heterogeneity of concrete was more actually. The stress-strain relationship of concrete under the different kinds of load was obtained through the numerical simulation calculation by using the elastic damage constitutive Relation. In this paper research work was summarized as follows:(1)The new random aggregate model of concrete was established by Ansys and Fortran program. In order to simulate the engineering practice, a new group of random aggregate models were established by changing the position of aggregate; these models had the same aggregate number but different position.(2) The P-S curve was obtained by the result of numerical simulation And strength criterion of concrete was defined from P-S curve(3) The static load and impact load was applied to the concrete. The static and dynamic strength change laws of the same load but different aggregate position were obtained from simulation result and P-S curve.(4) One of these models was chosen, and 4 types of impact load were applied to this model. The situation of strength changing and the relation between dynamic-static strength on this model was obtained (5) Cavity and inertia force ware successfully simulated by changing the parameters of the concrete. Thus the new concrete model was established. The new model was used to simulating. The effect of Cavity and inertia force to the strength of concrete was found by comparing the simulation result before.The mechanical properties and the situation of damage and failure element of concrete in different kinds of load were displayed in this paper. And a new method on study concrete was proposed.