3-D Numerical Simulation Of Meso-Damage Of Ceramsite Concrete Under Impact Loading

In this paper,the mechanical properties and meso-damage process of ceramsite concrete were researched by means ofsimulation.Based on meso-mechanics,the ceramsite concrete is simplified as two-phase composites material composed of ceramsite aggregate and mortar matrix.used the secondary development function of large-scale commercial software ANSYS/LS-DYNA,the 3-D numerical meso-model of ceramsite concrete was established.According to the size of the test samples,the mortar mix ratio and the volume fraction of ceramsite,the number of ceramsite aggregate is calculated.Based on the Monte Carlo random number method,the three-dimensional mathematical model of aggregate in the specimen and the spatial geometric model of ceramsite concrete is established.Based on this,used the "projection grid" modeling method to mesh the whole sample,and then ?se the secondary development function of ANSYS software to judge the aggregate and mortar matrix automatically.According to the mechanical parameters of each component of ceramsite concrete,the material properties of each component are assigned.The three-dimensional numerical meso-model of ceramsite concrete was established.Numerical simulation of bundled Hopkinson pressure bars test under different impact loads was carried out.The whole process of crack initiation,propagation,coalescence and failure of ceramsite concrete under different loads are obtained.The stress wave signals in the SHPB bar are obtained.The stress-strain curves of ceramsite concrete under different impact loads were reconstructed and that was in good agreement with the experimental result after compared.The dynamic compressive strength of ceramsite concrete was increased with the increase of the stress wave pulse load,it shows obvio?s strain rate effect,which shows that ceramsite concrete is strain rate sensitive materialThe simulation results show that the three-dimensional numerical model can simulate the meso-damage process of ceramsite concrete under different impact loads.The damage of the ceramsite concrete under different impact loads begins with the weaker ceramsite aggregate area,and then extends to the mortar matrix,resulting in the overall failure of the specimen.