Data from: Jammed frictional tetrahedra are hyperstatic

We prepare packings of frictional tetrahedra with volume fractions ϕ ranging from 0.469 to 0.622 using three different experimental protocols under isobaric conditions. Analysis via x-ray microtomography reveals that the contact number Z grows with ϕ, but does depend on the preparation protocol. While there exist four different types of contacts in tetrahedra packings, our analysis shows that the edge-to-face contacts contribute about 50% of the total increase in Z. The number of constraints per particle C increases also with ϕ and even the loosest packings are strongly hyperstatic, i.e., mechanically overdetermined with C approximately twice the degrees of freedom each particle possesses.本研究采用三种不同的实验方案，在等压条件下制备了体积分数ϕ介于0.469至0.622之间的摩擦性四面体填充体系。通过X射线显微断层扫描（X-ray microtomography）分析发现，接触数Z随体积分数ϕ升高而增大，且其数值依赖于制备方案。尽管四面体填充体系中存在四种不同类型的接触，分析结果表明边面接触（edge-to-face contacts）对接触数Z总增量的贡献约占50%。单颗粒约束数C同样随ϕ升高而增加，即使是最松散的填充体系也呈现出显著的超静定性，即其机械约束为过定状态，单颗粒约束数C约为自身自由度的两倍。