316 / 2023-05-04 10:43:17

Research on the phase evolution of debris clouds-陈小伟

高压物理与材料科学 > 动高压-I

The formation process of debris clouds is accompanied by material liquefaction and gasification. The material phase transition reduces its penetrability. It is difficult to observe and record the phase transition process with experimental methods. Therefore, numerical methods are usually used to study the phase transition of debris clouds. The FE-SPH algorithm is used in LS-DYNA, combined with the self-written phase partition program to explore the phase evolution law of the debris clouds. The phase partition of materials is divided into solid phase, thermal melting phase, liquid phase, thermal liquid phase and gas phase. The temperature failure criterion is added to the calculation, combined with the Johnson-Cook failure criterion and the maximum tensile stress failure criterion. When the material meets one of the failure criterion, the Lagrangian unit is converted into SPH particles to participate in the subsequent calculation. The temperature fields of different failure criterion at 8km/s are shown in Figure 1. Lagrangian units are used to represent the solid phase, and SPH particles are used to represent the other phases. Combined with the AL pressure-temperature phase diagram, the applicable ranges of the temperature method, the pressure method and the combined criterion method are compared; the phase distribution results show that the phase results obtained by the temperature method and the combined criterion method are relatively close, and the pressure method is not applicable at relatively low impact velocities(such as 5 km/s). The phase evolution law of Al under different impact velocities is summarized, which provides a reference for the research on the phase of hypervelocity impact. Figure 2 shows the maximum temperature field and phase field of the Lagrangian/SPH particles at different impact velocities for the projectile target model with a thickness-to-diameter ratio of t/d=0.3.