砂への飛翔体高速貫入時における力の伝わり方の数値解析的検討

抄録

We performed numerical analysis of high speed penetration into sand to compare with experimental result. Numerical analysis can visualize and digitize behavior of sand and a projectile. On the other hand, in the experiment, methods which can measure inside of granular material sequentially are exceedingly limited. Therefore, numerical analysis also plays an important role. The impact experiments were performed at a speed of 146509 m/s by using a powder gun. Packing density of sand was around 1.34×103 kg/m3. Impact and penetration speed of the projectile were temporally measured by coil method that is contactless. Smoothed Particle Hydrodynamics (“SPH”) was used as analytical method, because SPH is good at simulating with large deformation such as convection and ejection of sand. Equation of state (“EOS”) and constitutive equation were same as previous research. In order to simulate sand used in the experiments, input data of EOS and constitutive equation were collected and estimated from our experiments and previous research by Hagiwara, et al. Regarding penetration velocity history and penetration depth history, a numerical analysis model based on new input data was better agreement with experimental result than a numerical analysis model based on input data of previous work. Agreement with penetration speed history suggests that the numerical analysis model based on new input data can simulate forces exerted to the projectile and absorption energy of sand accurately.