Tomonori Ohno

Experiment and numerical simulation of double-layered RC plates under impact loadings

This paper is to investigate and to propose a method to improve the impact resistance of reinforced concrete (RC) plates against projectile impact, and the damage of double-layered RC plates is examined experimentally and simulated analytically. In tests, a projectile launching apparatus, which is a 40 mm smooth-bore airgun, was used. Based on experimental results, numerical simulations with the DYNA-3D code, which takes account of the dynamic constitutive law of concrete, were done to find the applicability of the present computer code to the analysis of double-layered RC plates under high-speed impact loadings. In this study, the impact resistance of concrete plate is defined as the degree of local damage. In both experiments and numerical simulations, the effect of double-layering on the impact resistance is discussed.

Internal explosion tests for scaled subsurface magazines

A subsurface magazine is proposed to reduce the debris and the air-blast pressure caused by an accidental explosion. First, 1/20-scale indoor explosion model tests for subsurface magazines were conducted to examine the characteristics of an air-burst and ground shock vibration. It was found from the test results that the peak blast pressure (P0) for an overburden thickness (T) of 50 cm was 0.84–0.98 times that for T = 15 cm, and the P0 for a loading density R = 9.0 kg/m3 was 1.09–1.39 times that for R = 4.5 kg/m3. It was also found that the maximum ground shock velocity Vmax for T = 50 cm was 0.57–1.07 times that for T = 15 cm. Second, the P0 was formulated as a function of the scaled distance Z, T, and R. Third, the Vmax was formulated as a function of Z and T. Finally, these formulae were validated using the test data obtained by performing a 1/10-scale field test.