This is a 2D companion to the 3D Ice Fracture simulator. It runs a genuine linear-elastic-fracture-mechanics loop instead of a decorative particle field:
- Stress concentration at the tip: each crack tip carries a stress-intensity factor K = σ·√(π·a), where σ is the local far-field stress (background load plus any decaying impact) and a is the crack's grown length. A tip only advances once K exceeds the material's fracture toughness Kc.
- Path following: at every growth step the tip samples the stress field along several candidate headings and turns toward the one carrying the highest stress — cracks bend toward load concentrations instead of moving in straight lines.
- Branching: once K climbs past roughly 1.9× Kc, the tip forks — the parent keeps going with reduced driving stress and a sibling peels off at a fixed angle, capped so the crack network doesn't explode without bound.
- Voronoi shatter: a hard click (impact strength above the shatter threshold) or a runaway tip (K past ~4× Kc) fragments a local disc of ice into a true bounded Voronoi diagram — random seed points clipped against each other's perpendicular bisectors — and the resulting polygon shards fly outward and settle.
Click or tap the ice to strike it. Raise the background load to watch the sheet crack on its own from pre-existing micro-flaws once toughness is exceeded everywhere at once.