IPS-C — Anisotropic Expansion and Layer Separation in Water-Filled Elastic Cellular Matrices

Layer separation — propagating detachment of adjacent blob layers due to IPS overpressure — is the most serious structural failure mode in the Adaptive Matrix Ecosystem. This paper derives a theoretical basis suggesting that layer separation arrests passively and automatically. The no-air-no-vacuum axiom guarantees that any gap fills immediately with water at the local hydrostatic pressure, producing a pressure differential of exactly zero at the separation front (ΔP_f = 0, always). Arrest occurs in milliseconds without sensor detection or control action. An eight-state machine describes the complete damage-arrest-repair sequence: separation initiates (instantaneous), propagates at the Rayleigh wave velocity of the saturated matrix (270.58 m/s, microseconds), arrests passively (milliseconds), reaches equilibrium (seconds), is detected by DFOS (minutes), assessed by the Cortex (seconds), and repaired by AMW dispatch (minutes to hours). The structure becomes safe at State 5 — before DFOS observes at State 6. Active re-seating of separated layers is shown to have no safe operating window: the set of pressures that re-seat existing gaps without creating new gaps is empty. The failure zone has an elliptical geometry with semi-axis ratio b/a ≈ 2/3, depth-invariant. Passive arrest is the most important safety result in the AME engineering programme: the structure's default response to its worst failure mode is automatic containment.