Numerical Simulation Of Plasma Characteristics Generated By The Hyperveloctiy Impact

With more and more human space activities,the space debris increases every year andspace environment is gradually worsening which has affected the on-orbit spacecraftsgreatly. Aerospace sector needs to strengthen the protection of spacecrafts and slows downthe risk of the collisions between spacecrafts and debris. The damage to spacecrafts causedby the hypervelocity impact from Space debris is mainly reflected in the spacecraftstructure and electronic equipments.In my paper,the characteristics of the plasma generated by hypervelocity impacts areexplored by theoretical analysis and numerical simulation in the current study. The mainworks are as following:Firstly, the model of hypervelocity impacts between aluminum spherical projectile andaluminum target is established by SPH numerical simulation method. The numericalsimulation is carried out under those conditions: the range of impact velocity is5km/s-18km/s, respectively, under the impact angle of30°,45°,60°,90°. Based on atomiccollision theory, at a temperature equilibrium system, my paper used Thomas-Fermi (TF)equation to calculate the temperature of SPH particles during the process of hypervelocityimpact, in order to judge whether the material is vaporized, we should consider the plasmaparameters of the vaporized particles. Then the chemical reaction rate equation isprogrammed into the three-dimensional SPH procedures to obtain the characteristicparameters of the plasma generated by hypervelocity impact, compared with the experienceto verify the validity of the model.Secondly, compared with experimental images and empirical formula, the results ofnumerical simulation presented debris cloud distribution of different moment and the lengthof target major and minor perforation, to get the extent of the damage of different impactvelocity and impact angle. So, we can predict the extent of damage to the spacecraft underdifferent conditions.Finally, according to Runge-Kutta method, the chemical reaction rate equation isprogrammed into SPH procedures to obtain the charges of the plasma, compared withempirical formula to varify the proposed Numerical Simulation methods. By analyzing therelationship between the charges obtained by numerical simulation of this paper and theimpact velocity, there must be a critical velocity in the empirical formula. Compared withthe charges of empirical formula, this critical velocity is close to the velocity of the material melting. Through the numerical simulation of different impact angles, we will get thecritical velocities of each impact angles.