Dnv-rp-f118

Short summary — key points from DNV‑RP‑F118

• Scope: Methods to estimate ice loads on ships, offshore structures and marine installations in level ice and broken-ice conditions for design and assessment.
• Ice properties: Classification of ice types, typical mechanical properties (compressive strength, flexural strength, Young’s modulus) and how temperature, salinity and grain structure affect them.
• Load-generating mechanisms: Descriptions of failure modes (flexure, crushing, splitting, bending, indentation) and interaction scenarios (continuous drift, grounded ice, ridges, icebergs).
• Design ice thickness and statistics: Guidance on selecting representative ice thickness, return periods, and using probabilistic approaches for extreme-event loads.
• Deterministic load models: Empirical and semi-empirical formulas for local and global ice pressures, bearing capacity, and ice-structure contact pressure distributions.
• Probabilistic methods: Treatment of uncertainties in ice properties, encounter frequency, and variables; methods to derive characteristic loads for target reliability levels.
• Dynamic interactions: Consideration of relative motions, velocity effects, and energy dissipation during ice impacts.
• Numerical modelling: Recommendations for using FEM, discrete-element and other computational models; calibration and validation against tests/field data.
• Testing and validation: Recommended laboratory and field tests for deriving parameters and validating models (compression, bending, indentation, model-scale interaction tests).
• Safety and design checks: Suggested acceptance criteria, load combinations, and considerations for inspection, monitoring and operational mitigation.

Standardization: Provide a fair basis for evaluating different AUT systems to ensure they comply with fracture mechanics-based acceptance criteria (e.g., Engineering Criticality Assessment). The Qualification Process

Critical load combinations include:

Further Resources

• Download DNV-RP-F118: [DNV Official Website] (current valid edition)
• Complementary standards: DNVGL-RP-C203 (Fatigue), DNVGL-ST-F201 (Dynamic Risers), API 17J (Flexible Pipe)
• Recommended software: OrcaFlex, DeepLines, Riflex, SHEAR7, VIVA