SPH Numerical Simulation Investigation On Reactive Damage And Electromagnetic Characteristics Of Plasma

Smoothed Particle Hydrodynamics(SPH)method is a fully Lagrange meshless numerical technique,it can get rid of the constraints of grid.Compared with traditional grid method,SPH method has unique advantages,is particularly suitable for simulation involving large deformation and high speed impact.In this thesis,based on the advantages of the SPH method,an impact dynamics platform was built by using Fortran programming language,and some advanced issues in high efficiency damage were conducted after verification procedures,the main work of this thesis has been listed as follows:(1)With the change of modern battlefield environment,the shaped charge warhead of traditional material cover has been unable to meet the requirements of modern war.In this thesis,the damage properties of a new type shaped charge warhead of PTFE/Al reactive material were studied.The models of reactive material were added into the SPH impact dynamic platform.On the basis of verifying the reliability of the selected material models,we simulated the process that generated the coupling effect of kinetic energy penetration and internal explosion.By a series of numerical simulations,we obtained that the damage effect of the PTFE/Al reactive material shaped charge warhead was stronger than the traditional,the damage probability to armor target was higher,and it could produce more powerful damage especially after penetrating through the first plate.The influence of the blasting height on the damage effects was analyzed yet.(2)Space activities are often threatened from hypervelocity impact by debris and meteoroids at the velocity of several kilometers per second and even tens of kilometers per second.The non-equilibrium ionization model considering electron temperature was applied in this thesis,the plasma charge generation during hypervelocity impact was calculated by the chemical reaction rate based on Arrhenius equation,and the magnetic field intensity induced by plasma generation was obtained by the Biot-Savart law.The numerical simulations of hypervelocity impacts of an aluminum projectile on an aluminum target were conducted at different impact velocities and impact angles.With the increase of impact velocity,the electromagnetic effect produced by impact got more visible.When a projectile impacted on target under a low velocity,90°impact and the low angle impact such on 30°had more obvious electromagnetic characteristics.With the increase of impact velocity,electromagnetic effect generated by 30°impact was gradually lower than the other angle’s result,the electromagnetic characteristics generated by collision became stronger with the increase of impact angle.At last,an improved empirical formula with critical speed was proposed.Some basements for optimizing protections from the plasma generated by hypervelocity impact were provided.