Characteristics Of Debris Cloud Produced By Normal Hypervelocity Impact Of Spherical Projectile With Thin Aluminum Plate

Space activity is an important reflection of one country's comprehensive strength. It plays an important role in national defense and people live hood. In recent years, the world's space activities are increasingly frequent. Spacecraft operations in outer space will be affecting by the space environment. Among them, space debris and micrometeoroids are threat spacecraft by their impact. Space debris are the result of solid residuals in human space activities. There are around the orbit of spacecraft, so it is even more serious threat. Space debris which grater than 10cm could be tracked detection by ground and space observations, so they may be eluded. For small debris that can not be observation effectively, it could only be used in the form of passive protection.Whipple shield is a method of spacecraft protection proposed by Whipple, who is an American scientist, in 1947. It has been used in practice successfully, and obtains wonderful effect. Its notion is put a bumper in front of spacecraft surface. Space debris broken into fragments when it impacts in the bumper, then impact energy reduces in unit area of spacecraft. In order to get quality shield system for spacecraft, evaluate the effect of shield caused concern. Given this demand, hypervelocity impact study developed. Hypervelocity is, namely: the shock pressure is far greater than the strength of projectile and plate.Based on this background, for China-made Al-2A12, through hypervelocity impact experiments, this paper get research of characters of debris cloud which caused by vertical impact between spherical projectile and thin plate. There are mechanical reasons for fragmentation of projectile when impact. First, we made a qualitative research for the fragment through theory of stress wave, and discussed requires for formation of debris cloud. Then made a series of hypervelocity impact experiments use two stage light gas gun and flash X-ray imaging system. Based on X-ray images and impacted plates, I made research in these aspects: character of fragment's size; amount of fragment; velocity of special points in debris cloud and perforation of the bumper. Through these researches, I got fitting functions for size of fragment,amount of fragment and diameter of bumper perforation. The work of this paper, is valuable in debris cloud modeling and assessment for spacecraft shield system.