MESOSCOPIC NUMERICAL SIMULATION ON DYNAMIC BIAXIAL TENSION-COMPRESSION FAILURE CRITERION OF CONCRETE

Concrete structures in normal service are often subject to complex stresses and are inevitably subject to the sporadic dynamic loads. The failure criterion is the foundation for the study of mechanical properties of concrete under complex loads. Limited by the test equipment and other conditions, the existing dynamic biaxial tension-compression strength failure criterion has a complex form, lacks of higher strain rate and lateral stress ratio range and has not yet considered the coupling effect of strain rate and lateral stress ratio comprehensively. In order to further propose a more applicable and accurate failure criterion of concrete dynamic biaxial tension-compression strength, a 3D random numerical model of cubic concrete is established on a mesoscale in this study. The dynamic tension-compression failure behavior of concrete materials under different strain rates and lateral stress ratios are simulated. The influence of strain rate and lateral stress ratio on the failure modes and dynamic biaxial strengths of concrete are discussed respectively. The failure criterion of dynamic biaxial tension-compression strength of concrete is put forward. The simulation results indicated that with the increase of strain rate and lateral stress ratio, the internal damage of concrete specimen increases and the number of cracks increase. Under dynamic biaxial tension-compression loads, with the increasing strain rate, the dynamic spindle compressive strength and dynamic lateral tensile strength of concrete increase gradually. With the increasing lateral stress ratio, the dynamic spindle compressive strength decreases while the dynamic lateral tensile strength increases. The dynamic biaxial Tension-Compression failure criterion of concrete proposed in this paper has the advantages of wide range of applicable strain rate and lateral stress ratio, concise form, no longer restricted by physical test conditions and considering the coupling effect of strain rate and lateral stress ratio, etc. The established failure criterion of concrete has been verified from different angles.