科研之友
微信
新浪微博
Facebook
分享链接
摘要
We analyse properties of contact networks formed in packings of soft frictionless disks near the unjamming transition. We construct polygonal tilings and triangulations of the contact network that partitions space into convex regions which are either covered or uncovered. This allows us to characterize the local spatial structure of the packing near the transition using well-defined geometric objects. We construct bounds on the number of polygons and triangulation vectors that appear in such packings. We study these networks using simulations of bidispersed disks interacting via a one-sided linear spring potential. We find that several underlying geometric distributions are reproducible and display self averaging properties. We find that the total covered area is a reliable real space parameter that can serve as a substitute for the packing fraction. We find that the unjamming transition occurs at a fraction of covered area A(G)* = 0.446(1). We determine scaling exponents of the excess covered area as the energy of the system approaches zero E-G -> 0(+), and the coordination number < z(g)> approaches its isostatic value Delta Z= < z(g)> - < z(g)>(iso) -> 0(+). We find Delta A(G) similar to Delta E-G(0.28(1)) and Delta A(G) similar to Delta Z(1.00(1)), representing new structural critical exponents. We use the distribution functions of local areas to study the underlying geometric disorder in the packings. We find that a finite fraction of order Psi(O)* = 0.369(1) persists as the transition is approached.
- 出版日期2016-11
