Deep-Water Winch Integrity

The Challenge

Deep-water multi-layer winch drums experience extreme radial pressures, with contact stresses reaching 1,500-2,000 MPa at crossover points. This frequently exceeds the 1,770 MPa yield stress of high-strength wire ropes.

Conventional models incorrectly assume a pressure plateau after 5 layers, hiding catastrophic failure modes like internal crushing and fretting fatigue. These damage mechanisms occur deep within the spooling, remaining invisible to surface inspections until a catastrophic release occurs.

Our Approach

We deploy Multi-Physics PINNs coupling a mechanical stress model (Dietz formulation) with a real-time thermal solver. The architecture accounts for layer-by-layer pressure and side-disc line loads.

By incorporating a multi-layer damage factor (2.85 + 0.65 \u00d7 Design Factor), the model infers internal rope health from tension history. Simultaneously, it tracks brake disc heat capacity to mitigate thermal fade during prolonged deep-water lifts.

Validation

The PINN surrogate achieved 94% agreement with offline ANSYS FEA peak stress predictions, reducing computation from hours to real-time. Thermal validation against instrumented winch data showed a Mean Absolute Error (MAE) of less than 5\u00b0C.

Recommendation

Initiate a 6-month pilot on subsea construction vessels with D/d ratios below 25. Success criteria include predicting thermal fade within \u00b15\u00b0C and detecting stress peaks exceeding 1,500 MPa before rope integrity is compromised.