Three-dimensional particle model based numerical simulation on multi-level compressive cyclic loading of concrete

Under the framework of the particle flow code (PFC), a three-dimensional multi-level stress corrosion model (MSC) is proposed to reproduce the mechanical behaviour of brittle geo-materials and concrete exposed to multi-level cyclic compressive loading. The damage induced by the variable cyclic load levels during consecutive loading stages in numerical simulations is quantitatively characterized by time-stress-dependent reducing of the bond diameter. The change of maximum or minimum load levels correspond to different evolution characteristics of the bond diameter. The simulation results with the adoption of the MSC model shows good consistency with laboratory testing. The MSC model is proved to replicate the mechanical characteristics of concrete samples subjected to cyclic loading with both, variable maximum and minimum load levels. A three-dimensional acoustic emission (AE) monitoring system is implemented into PFC3D. The cumulative AE energy collected during the simulation is designated as the released bond strain energy at bond breakage. The cumulative AE energy in the simulation shows good agreement with laboratory test results. (C) 2019 Elsevier Ltd. All rights reserved.