Study On Correlation Method Of Concrete Microscopic Characteristics And Macroscopic Shock Compression Behavior

A multi-scale method of concrete materials has been presented which bridges the meso-scale characters and macro-scale dynamic behavior. The meso-scale model has been built following the distribution of real structure. The behavior of concrete under dynamic and static loading has been analyzed with reduced-order homogenization method in two scales. The simulation results agree well with corresponding experimental data. The main contents and conclusions are as follows:(1) Methods for generating multi-phase meso-scale model of concreteConcrete was considered as a three-phase composite material composing of aggregates, mortar and the ITZ(Interfacial Transition Zone) phase for simplification. A random aggregate model, which followed the probability distribution of real structure, was established and used in FEM analysis. Algorithms for generating, distributing and meshing of random convex polyhedrons were presented. After disordering the distribution turns of aggregate and rebar, a reinforced concrete meso-scale model was established.(2) Reduced order homogenization method based on homogenization theoryEquations had been concluded from the asymptotic expansion of FEM equations in two scales based on homogenization theory and the meso-scale displacement field was constructed. Considering its compatibility with commercial finite element software ABAQUS and meso-scale model of concrete, solving steps of reduced order homogenization theory had been concluded with the idea of RVE(Representative Volume Element).(3) Two scale study on static mechanical properties of concrete based on reduced order homogenization theoryThe validity of concrete’s meso-scale model was verified through simulation of uniaxial static compression. Uniaxial static compression simulations of concretes with different strengths were conducted with the two-scale algorithm. It was shown that the two-scale simulation results agreed well with both the experimental results and the meso-scale simulation results.(4) Two scale study on dynamic behavior of concrete based on reduced order homogenization theoryBased on reduced order homogenization method, a two-scale computational constitutive law for concrete subjected to dynamic loading had been programmed. It has been shown that the constitutive model worked well with the results of Split Hopkinson Pressure Bar (SHPB) test under different strain rates. Then dynamic behavior of concretes with different strengths during the SHPB test were presented under the same strain rate to validate the advantage of the two-scale method.