The assessment of high velocity multi-impact damage in steel fiber reinforced cementitious composite panels

This paper presents a high velocity impact damage assessment of 100 mm thick steel fiber reinforced cementitious composite (SFRCC) panels of size 300 mm × 300 mm. The panels are tested using in-service munitions in field firing range under high velocity impacts of 5.56 mm and 7.62 mm calibre projectiles. Three consecutive normal impacts are made on each of the SFRCC panel within the damage zone of previous hits. The details of impact tests, procedure adopted for multi-impact damage assessment are described in the paper. Measurements are taken for depth of penetration, location of cracks, and crater sizes under first hit, as well as after consecutive hits. In order to quantify the damage in SFRCC panels under multiple impacts, both non-destructive testing (NDT) and destructive methods are adopted. For quantitative assessment of the internal overlapping damage zones, NDT using ultrasonic pulse velocity (UPV) measurement on a square grid spacing of 20 mm is carried out. Internal overlapping of damage zones due to multi-impacts on SFRCC panels are identified in non-destructive manner. To verify the effectiveness of the NDT method in multi-impact damage assessment, few SFRCC panels are dissected, using concrete cutting machine. Numerical simulation is also carried out to predict damaged area in the panels under multi-impacts. The damage contours obtained from numerical simulations are found to match with the damage zones detected using NDT method.