The dynamic properties of soil under impact loads are studied experimentally and numerically. By analyzing the microstructural photos of soils with and without impact, it is shown that impact loads can destroy the ori...The dynamic properties of soil under impact loads are studied experimentally and numerically. By analyzing the microstructural photos of soils with and without impact, it is shown that impact loads can destroy the original structures in the compact area, where the soil grains are rearranged regularly and form the compact whirlpool structure. Simultaneously, the dynamic impact process of soil is simulated by using the software of Ls-dyna. The time-dependent distribution of the dynamic stress and density is obtained in the soil. Furthermore, the simulation results are consistent with the experimental results. The reinforcement mechanism and the rule of dynamic compaction of soils due to impact load are also elucidated.展开更多
In this paper, numerical simulation of impact cases of liquid-filled tube impacted by missiles is conducted with a commercial finite element code LS-DYNA, and the results obtained are compared with the experimental da...In this paper, numerical simulation of impact cases of liquid-filled tube impacted by missiles is conducted with a commercial finite element code LS-DYNA, and the results obtained are compared with the experimental data to verify the validity of the numerical simulation model adopted. With the verified numerical method, the processes of dynamic response of a blunt indenter impacting an empty or liquid-filled three-span continuous tubular beam are studied when the parameter such ms the indenter＇s mass, liquid＇s density or impact velocity is varied and the other conditions are kept the same. The simulation results indicate that the criticM perforation energy and the deformation of the wall of the pipe are significantly influenced by the presence of the liquid and the pressure. The liquid filling the tube provides a ＇foundation＇ pressure to resist and localize the deformation, which may affect the perforation process and lead to a reduction of the ballistic limit. The simulation results also indicate that the increase of the fluid density filled in the tube will decrease the ballistic limit, but the fluid density must be in some scope. The relationship between the ballistic limit velocity of the tube and the mass of the impact missile is nonlinear in the Cartesian coordinate while it becomes linear through logarithmic transformation.展开更多
文摘The dynamic properties of soil under impact loads are studied experimentally and numerically. By analyzing the microstructural photos of soils with and without impact, it is shown that impact loads can destroy the original structures in the compact area, where the soil grains are rearranged regularly and form the compact whirlpool structure. Simultaneously, the dynamic impact process of soil is simulated by using the software of Ls-dyna. The time-dependent distribution of the dynamic stress and density is obtained in the soil. Furthermore, the simulation results are consistent with the experimental results. The reinforcement mechanism and the rule of dynamic compaction of soils due to impact load are also elucidated.
基金supported by the National Natural Science Foundation of China (Nos. 10702047 and 11072167)the Scientific Research Fund of Shanxi Province (No. 2008021006) and TSTIT
文摘In this paper, numerical simulation of impact cases of liquid-filled tube impacted by missiles is conducted with a commercial finite element code LS-DYNA, and the results obtained are compared with the experimental data to verify the validity of the numerical simulation model adopted. With the verified numerical method, the processes of dynamic response of a blunt indenter impacting an empty or liquid-filled three-span continuous tubular beam are studied when the parameter such ms the indenter＇s mass, liquid＇s density or impact velocity is varied and the other conditions are kept the same. The simulation results indicate that the criticM perforation energy and the deformation of the wall of the pipe are significantly influenced by the presence of the liquid and the pressure. The liquid filling the tube provides a ＇foundation＇ pressure to resist and localize the deformation, which may affect the perforation process and lead to a reduction of the ballistic limit. The simulation results also indicate that the increase of the fluid density filled in the tube will decrease the ballistic limit, but the fluid density must be in some scope. The relationship between the ballistic limit velocity of the tube and the mass of the impact missile is nonlinear in the Cartesian coordinate while it becomes linear through logarithmic transformation.
