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We perform herein a direct observation of shockwave propagation using a high-speed camera and estimate properties, such as acoustic velocity and Hugoniot parameter, using the impedance matching scheme to reveal the dynamic characteristics of Okinawa's unique soil "Shimajiri Mahji." A computational simulation corresponding to the experimental setup is then conducted. A comparison of the numerical and experimental results demonstrates their fairly good agreement, which suggests that the experimentally estimated dynamic characteristics of "Shimajiri Mahji" are valid. In addition, a computational simulation based on the smoothed particle hydrodynamics is also modeled and performed to elucidate the fragment behavior when the unexploded bomb explosive is at the soil surface. From a series of computational results, we have confirmed and clarified that the fragment behavior is significantly dependent on the amount of explosive charge and soil characteristics. [ABSTRACT FROM AUTHOR]

To clarify the shock characteristics of Okinawa's unique soils "Jahgaru" that is widely distributed in southern part of Okinawa Main Island, an experimental investigation of dynamics properties such as shockwave propagation, pressure and particle velocity have been performed using impedance matching method. Therefore, we have also obtained the Hugoniot date of "Jahgaru". And then, to reveal a validity of the material characteristics, a computational model for the experimental procedure using ALE simulation have been developed. A comparison between numerical results and experimental ones, the capability of proposed method through the numerical simulations have been confirmed. [ABSTRACT FROM AUTHOR]