The Studies Of SPH Simulation For The Hot-mechanical Effects Of Pulsed X-ray Irradiating The Multilayer Containing Gap Material

When the pulse X-rays irradiate material, X-rays will interact with the atoms in thematerial, the energy of X-ray is converted into material’ internal energy, and heat isgenerated in the surface of the material, which will make the material gasification, whilethermal shock wave is formed in the material, the thermal shock wave’propagation andreflection in the material may destroy material. In order to reduce the destruction,generally, it will lay multi-layer composite material in the surface to achieve thepurpose of weakening thermal shock wave intensity. When laying the multilayermaterial in the surface, as layers of material are not all sticking together and therefore，there will be a certain gap between them. The presence of the gap may effect theimpulse and the propagation of thermal shock wave. However, the existence of the gapwill be a great difficult for the simulation based on grid technology, therefore, it isimportant practical significance to take the appropriate method for the simulation inmultilayer discontinuous medium.Smoothed Particle Hydrodynamic(SPH) is a Lagrangian and meshless method. Notonly it preserves the advantage to describe the material interface, but also it’s logic issimple and is able to avoid the grid winding and twisting which will happen in finiteelement method and finite difference method. but SPH don’t have a good way to dealwith the problem of gasification boundary. therefore, this paper use SPH for thenumerical simulation of the thermal and mechanical effect that X-ray irradiatemultilayer structure and in the gasification border we use the method of mathematicalinterpolation basing on momentum conservation equation.The results of numerical simulation show that the SPH method is feasible for thesimulation of the thermal and mechanical effect when pulse X-ray irradiate multilayerincluding gap materials, and the gasification boundary treatment is also successful inthis paper.The results of numerical simulation also show that the gap between thematerial have a large impact to thermal and mechanical effects. when soft X-rayirradiation, gap will weaken the thermal shock wave intensity, and the greater the gapwill be, the more attenuation the thermal shock wave will have. when hard X-rayirradiation, the impact of the gap is more complicated, it lies on the material structuremodel.