Vessel Structural-Health-Monitoring Interface

Distributed strain, displacement, and acoustic sensing on the vessel feed the twin's fatigue model and a slow structural-alarm path.

What it watches

Both machines subject their vacuum vessels to large, cyclic electromagnetic and thermal loads — the breeder from disruptions and the 9.66 MA current, the burner from its mirror fields and thermal cycling. The structural-health-monitoring (SHM) interface instruments the vessel so cumulative damage is tracked long before it becomes a fault.

Sensor set

• Distributed strain (fiber and foil gauges) at high-stress nodes.
• Displacement/proximity sensors across joints and supports.
• Acoustic-emission sensors for crack-initiation precursors.
• Temperature for thermal-load correlation.

# rainflow fatigue accumulation (twin, slow loop)
cycles = rainflow(strain_history[node])
for (amp, mean, n) in cycles:
    D[node] += n / N_allow(amp, mean)     # Miner's rule
if D[node] > D_warn:
    schedule_inspection(node)             # predictive maintenance

Two paths

The fast path is a simple limit alarm owned by L1; it exists for gross overstress, not routine control. The valuable path is slow: the twin integrates strain cycles into a damage estimate (Miner's rule via rainflow counting) that drives predictive maintenance and spare-parts planning.

Owner: sense-side L2; fatigue model L3; maintenance L4/L7. Calibration ties gauges to a known load and tracks drift so accumulated damage is never computed through a stale sensor. Design-and-simulation specification, exercised against the twin's thermomechanics module.