The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation resul...The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is verified.Different shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are simulated.The influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was obtained.With an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is prolonged.The projectile decelerates slowly,resulting in a larger cratering depth.The energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer coefficient.The numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase transition.The results can provide theoretical guidance for kinetic impactor design and material selection.展开更多
In this research, we studied the distribution of impact melt layers underneath Xiuyan crater using hydrocode simulation. The target was modeled by granite based on the rock type distribution around the crater and proj...In this research, we studied the distribution of impact melt layers underneath Xiuyan crater using hydrocode simulation. The target was modeled by granite based on the rock type distribution around the crater and projector by iron, because most small and isolated terrestrial craters are formed by iron projectile. The simulated crater diameter and depth are 1 710 and 320 m, respectively, which are in good agreement with observations of 1 800 and 307 m（except for the postimpact lacustrine sedimentation）. The validated model shows that impact melt materials were first formed along the transient crater floor and wall by highshock pressure, and then refilled inward the crater along with collapse of the crater wall. The final style of impact melt materials is interbedded with shock breccia underneath the crater center, which is verified through two layers in the borehole located in the crater center.展开更多
基金the National Natural Science Foundation of China(Grant Nos.62227901,12202068)the Civil Aerospace Pre-research Project(Grant No.D020304).
文摘The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical simulation.By comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is verified.Different shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are simulated.The influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was obtained.With an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is prolonged.The projectile decelerates slowly,resulting in a larger cratering depth.The energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer coefficient.The numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase transition.The results can provide theoretical guidance for kinetic impactor design and material selection.
基金supported by the National Natural Science Foundation of China (Nos.41472303,41490635)
文摘In this research, we studied the distribution of impact melt layers underneath Xiuyan crater using hydrocode simulation. The target was modeled by granite based on the rock type distribution around the crater and projector by iron, because most small and isolated terrestrial craters are formed by iron projectile. The simulated crater diameter and depth are 1 710 and 320 m, respectively, which are in good agreement with observations of 1 800 and 307 m（except for the postimpact lacustrine sedimentation）. The validated model shows that impact melt materials were first formed along the transient crater floor and wall by highshock pressure, and then refilled inward the crater along with collapse of the crater wall. The final style of impact melt materials is interbedded with shock breccia underneath the crater center, which is verified through two layers in the borehole located in the crater center.
