Evaluation of local damage to reinforced concrete panels subjected to oblique impact by soft missile

Abstract

Many empirical formulas have been proposed for evaluating local damage to reinforced concrete structures caused by impacts of rigid missiles. Most of these formulas have been derived based on tests involving impact perpendicular to target structures. Thus far, few tests with oblique impact onto target structures have been carried out. In this study, we aim to propose a new formula for evaluating the local damage caused by oblique impact based on previous experimental and simulation results. In this study, we perform simulation analyses for evaluating the local damage to reinforced concrete panels subjected to oblique impacts by soft missiles under various impact velocities by using a simulation method that was validated using the results of previous impact experiments. Based on the results of these simulation analyses, quantitative evaluation of the reduction in local damage due to the difference in impact angle and impact velocity is investigated.

Analytical study of perforation damage in reinforced concrete slabs subjected to oblique impact by projectiles with different nose shapes

“…Based on our previous work (Nishida et al, 2018(Nishida et al, , 2019, the proposed analytical method in terms of calibration analysis was validated by compared with the experimental results derived from the aforementioned small-scale impact tests (Fig. 2).…”

“…The target RC slab used in this simulation analysis is the same as the reference (Nishida et al, 2019) shown in Fig. 4.…”

“…For oblique impact, there is only a few experimental results available for research and Ohta et al (2017) developed a new formula to predict local damage induced by oblique impact of rigid projectile based on test data (Richard and Stipe, 1943) by means of integrating correction factors regarding projectile diameter, slip and rebound effects with the modified NDRC formula (Kennedy, 1976). Recently, simulation analysis for evaluation of the penetration and perforation damage to RC slabs subjected to oblique impact has been conducted and corresponding interpretation on analytical results has been provided in detail (Nishida et al, 2018(Nishida et al, , 2019Kang et al, 2019Kang et al, , 2020.…”

“…To assess the residual velocity of a projectile after the occurrence of perforation damage, impact formulas have been developed to determine the value of residual velocity used to investigate the effects of projectiles in diverse targets such as soil, concrete or steel plate based on energy conservation (Kar, 1979). As for impact angle, an evaluation study of the perforation of RC slabs arising from oblique impact by a soft projectile has been conducted by (Nishida et al, 2019). Specially, it was confirmed that there are such cases that the residual velocity after perforation to RC slab in case of oblique impact was higher than that in case of normal impact under certain conditions.…”

Failure analysis of semi-infinite concrete targets subjected to tubular projectiles impact

“…They found that the impact force-time history measured in the experiment is in good agreement with that calculated using the modified Riera model. The finite element code LS-DYNA with Lagrange finite elements and explicit time integration was used, by Nishida et al [27], to study the damage of reinforced concrete subjected to oblique impact by soft missile at various impact velocities and angles. The material model of the concrete employed in the simulation analyses was the Winfrith model (MAT #084) installed in LS-DYNA.…”