ZHANG Sheng, LU Yi-qiang, WANG Qi-zhi. Measurement of dynamic fracture propagation toughness of rock and observation of dynamic arrest phenomenon using P-CCNBD specimens[J]. 2017, 38(11): 3095-3105.
ZHANG Sheng, LU Yi-qiang, WANG Qi-zhi. Measurement of dynamic fracture propagation toughness of rock and observation of dynamic arrest phenomenon using P-CCNBD specimens[J]. 2017, 38(11): 3095-3105.DOI: 10.16285/j.rsm.2017.11.003.
much attention has been made on the whole process of dynamic fracture
including crack initiation
propagation and arrest. This study mainly aims to investigate the propagation and arrest of rock under dynamic loading. Experiments were conducted on pre-cracked chevron notched Brazilian disc (P-CCNBD) specimens with a large diameter ( 160 mm) by using split Hopkinson pressure bar (SHPB). Then we determined mode-I dynamic initiation toughness and propagation toughness of marble. Since the employed large-size specimens did not satisfy the stress equilibrium condition in the dynamic test
the papular quasi-static method could not be applied in this study. Hence
an experimental-numerical-analytical method was adopted. The crack initiation time and the crack propagation velocity were monitored by using strain gauges and crack propagation gauges. The recorded experimental data
including dynamic loads applied to the specimens by SHPB
were simulated by 3D finite element analysis program. Then the time history of dynamic stress intensity factor of P-CCNBD was obtained by using the semi-analytical modification with an universal function. The results show that the dynamic initiation toughness of P-CCNBD marble specimen increases with the increase of loading rate. Dynamic propagation toughness of P-CCNBD marble specimen is slightly lower than dynamic initiation toughness. Moreover
dynamic propagation toughness increases with crack propagation velocity. In addition
the oscillation of crack propagation velocity and propagation path deflection were analyzed
and the possibility of achieving crack dynamic arrest in P-CCNBD was discussed as well.