Auxetic Metamaterial — Negative Poisson's Ratio

Re-entrant honeycomb auxetic structure: stretching it vertically makes it expand horizontally (ν < 0). The ribs rotate and unfold. Adjust the re-entrant angle and pull strength to see the counterintuitive expansion.

Re-entrant angle θ: 30°

Pull strain ε: 0.0

Rib aspect h/l: 1.5

Poisson's ratio:

ν = 0.00

For re-entrant honeycomb:

ν = −sin²θ(h/l + sinθ) / cos²θ(h/l + sinθ)