Research On The Damage Of Space Debris Hitting Astronaut’s Bone-muscle Tissue At High Speed

With the continuous development of human aerospace industry,the number of orbiting spacecraft in space continues to increase,and a large number of space activities have led to a substantial increase in the number of space debris in the space environment.At the same time,as the missions performed by spacecraft become more and more diversified,astronauts often have to perform spacewalks and other missions outside the capsule.Therefore,both the space debris itself or the secondary debris generated after the spacecraft is impacted may cause impact damage to the astronaut.Based on the above background,this article takes the bones and skeletal-muscle tissues of the human body as the research objects,uses numerical simulation and theoretical analysis methods to focus on the damage effects of projectiles after impact,and summarizes the impact laws of high-speed section.The main research contents of this paper are as follows:The damage characteristics of the projectile directly hitting bone and bonemuscle tissue were studied.By comparing with the experimental results of the existing literature,the validity of the numerical simulation is verified.Through the analysis of numerical simulation results of spherical projectiles with different diameters and speeds hitting bones and bone-muscle tissues,different penetration depths and damage morphologies were obtained.The results show that aluminum ball projectiles with a diameter of 3mm and above have greater damage to bones and bone-muscle tissue;aluminum ball projectiles with a diameter of 4mm and above and a high speed will have cracks when they hit the bones.At the same time,there will be cavities in the muscles,causing damage.The damage characteristics of bone and bone-muscle tissue after the projectile hits the spacesuit at high speed are studied.The damage of each layer structure after the spherical aluminum projectiles of different diameters and speeds hit the equivalent structure of the spacesuit is obtained by numerical simulation.The results show that,within the impact simulation speed range of this article,the spacesuit structure can better protect the human body from the impact damage of the 2mm diameter aluminum ball projectile,while the impact protection effect on the 3mm diameter aluminum ball projectile is weakened,but the impact protection effect on the 4mm and 5mm aluminum balls The projectile protection effect is poor,and the astronauts will still suffer more serious damage.At the same time,a projectile with excessive impact energy will tear the muscle laterally and create a discontinuous cavity in the muscle.The theories of the entrance diameter and penetration depth of the projectiles penetrating the gelatin and the empirical formula of the impact velocity in the range of 1km/s-3km/s are studied.The section density of the projectile and the retardation coefficient of the material and other parameters are introduced into the formula.The results show that for the high-speed penetration of the aluminum ball projectile into the gelatin,the impact energy is proportional to the product of the cross-sectional density and the square of the entrance diameter;the penetration depth is related to the material retardation coefficient and the penetration speed.At the same time,millimeter-level aluminum ball projectiles with a penetration speed of more than1km/s need to consume more energy to enter the gelatin;the formula coefficient of the penetration depth of the millimeter-level aluminum ball with a speed of 1km/s-3km/s is higher than that at a speed of 1km/s.Compared with the formula coefficient of the penetration depth of the millimeter steel ball below s,the gelatin depth has increased by about 23%.