The phase behavior of inertial active particles in two dimensions is investigated numerically by using structural and dynamical freezing criteria, and melting criterion with a modified Lindemann parameter. It is found that inertial active particles can crystallize at sufficiently high densities. Comparing to the overdamped active particles, the inertia hinders crystallization of inertial active particles. For a given damping coefficient, structural and dynamical freezing criteria are different, and do not coincide for any self-propelling force due to the competition of dissipation and the inertial effect. Because the increasing inertia suppresses the effect of self-propulsion force, the transition region between liquid and solid becomes wider and the position of this region shifts downward to small coupling strength with damping coefficient. There is no structural difference between two suspensions with different inertia in the liquid phase because diffusion dominates the dynamics. Whereas the suspension for large damping coefficient is more structured on the whole but there exist well-separated liquid-like bubbles in the transition region. In addition, it is very difficult to crystallize into the perfect hexagonal crystal for small damping coefficient, which needs very large coupling strength due to the inertial effect.

通过使用结构和动态冻结准则以及具有修正 Lindemann 参数的熔化准则，对二维惯性活性粒子的相行为进行了数值研究。发现惯性活性粒子可以以足够高的密度结晶。与过阻尼活性粒子相比，惯性阻碍了惯性活性粒子的结晶。对于给定的阻尼系数，结构和动力冻结标准是不同的，由于耗散和惯性效应的竞争，任何自推进力都不一致。由于惯性的增加抑制了自推进力的作用，液体和固体之间的过渡区域变宽，该区域的位置向下移动到具有阻尼系数的小耦合强度。在液相中具有不同惯性的两种悬浮液之间没有结构差异，因为扩散在动力学中占主导地位。而大阻尼系数的悬架整体上更有条理，但在过渡区存在分离良好的液状气泡。另外，阻尼系数小，很难结晶成完美的六方晶体，由于惯性效应，需要非常大的耦合强度。