Loading rate effects on cracking behavior of flaw-contained specimens under uniaxial compression

Abstract

To investigate the loading rate effects on the cracking processes of flaw-contained specimens under compressive loading, rectangular parallelepiped specimens containing centrally located single and double flaw(s) are numerically loaded using the bonded-particle model (BPM). The study reveals that the uniaxial compressive stress (σ c) and coalescence stress (σ c) increase significantly, while the first crack initiation stress (σ ci) only subtly increases with the increase of loading rate. The trajectories of the first and secondary cracks become shorter while the amount of discrete micro-cracks increases as the loading rate increases. The mode of coalescence cracks changes from tensile-segments-dominant to shear-band-dominant when the loading rate increases. The shape of the stress-strain curves of specimens loaded at different rates also varies. Based on the present study, an upper limit of loading rate of 0.08 m/s deems to be acceptable for cracking processes analysis under static load using the BPM. © 2013 Springer Science+Business Media Dordrecht.