Investigation of crack dynamic parameters and crack arresting technique in concrete under impacts

Abstract

Concrete structures usually contain cracks or microcracks. Under dynamic loading, such as impacts, blasts and earthquakes, these cracks may initiate and propagate, weakening concrete strength and structure’s stability. It is thus necessary to carry out the research on the crack dynamic fracture behavior and to develop crack arresting technique for cracked concrete structures under dynamic loads. In this study, impact tests were performed using a drop-weight impact device. A single crack emanating from a semicircle and a V-shaped bottom (SCESVB) specimen was proposed. The V-shaped bottom has the function of arrest on the propagation of the pre-crack. Crack propagation gauges (CPGs) were used to measure crack propagation parameters. Three angles 120°, 150° and 180° were designed for the V-shaped bottom of the SCESVB specimens. The crack propagation behavior was simulated by the finite difference code AUTODYN, and the dynamic stress intensity factor (DSIF) was calculated by the finite element code ABAQUS. The critical DSIF was determined by the crack initiation time and the propagation time measured by the CPG. The experimental and numerical simulation results show that the SCESVB specimen is suited to studying crack propagation behavior and crack arresting behavior for concrete under dynamic loads. During the crack propagation process, the crack may arrest in a short time, and the critical DSIF at initiation is higher than that at propagation for the concrete.