Hard-sphere packing generation with the Lubachevsky–Stillinger (LS) algorithm. We set N=500, and change the expansion rate of particles to obtain many packing samples. 每个压缩率下算300个样本 可以参照https://pubs.rsc.org/en/content/articlepdf/2014/sm/c3sm52959b来写
面临的问题：0.7以上少，考虑引入defect？
另：对rattler问题要有交代，至少是collectively jammed。
Although these packings are obtained under differ�ent conditions, structural analysis suggests that these samples are consistent with each other for a given ρ ------ On the relationships between structural properties and packing density of uniform spheres
Nevertheless, the LS compression protocol is an excellent tool to approach the jamming point: Besides being fast, it has been amply verified that it closely reproduces the (phenomenological) equation of state ------ Hard-sphere jamming through the lens of linear optimization
DEM涉及到软球； 体积模量（B）关注的比较少，可以直接算出来 软球 lammps去掉friction 或LS生成初始结构，压缩使得所有颗粒重叠，再能量最小化
思路：压强与order双向增加PD， bcc用pathy model，到Corey主页搜K. Zhang，
Mechanical Characterization of Partially Crystallized Sphere Packings附件里有提到新的RDF计算方法
Mechanical Characterization of Partially Crystallized Sphere Packings里的Zg和Zm
Zg的计算：
这里的本构和dem怎么建模，可以参考Mechanical Characterization of Partially Crystallized Sphere Packings。
有篇名为structural and mechanical characteristics of sphere packings near the jamming trainsition值得看一下。