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Verify OrcaFlex model results against industry standards (DNV, API, ISO) with automated capacity checks and compliance reporting.
Version Metadata
version: 1.0.0
python_min_version: '3.10'
dependencies:
orcaflex-modeling: '>=2.0.0,<3.0.0'
structural-analysis: '>=1.0.0,<2.0.0'
orcaflex_version: '>=11.0'
compatibility:
tested_python:
- '3.10'
- '3.11'
- '3.12'
- '3.13'
os:
- Windows
- Linux
- macOS
Changelog
[1.0.0] - 2026-01-17
Added:
- Initial release with standards compliance checking
- Mooring line capacity verification
- Safety factor calculation
- Multi-standard support (DNV, API, ISO)
When to Use
- Verify mooring line tensions against MBL limits
- Check riser stress against allowable
- Validate safety factors per design codes
- Generate compliance reports for certification
- Design verification before fabrication
- Audit existing designs against current standards
Supported Standards
Mooring Systems
| Standard | Application | Key Checks | |----------|-------------|------------| | API RP 2SK | Stationkeeping | Safety factors, line capacity | | DNV-OS-E301 | Position mooring | Tension limits, fatigue | | ISO 19901-7 | Mooring systems | Capacity, redundancy |
Risers
| Standard | Application | Key Checks | |----------|-------------|------------| | API RP 2RD | Riser design | Stress, fatigue | | DNV-OS-F201 | Dynamic risers | Stress, VIV | | API STD 2RD | Design of risers | Combined loading |
Pipelines
| Standard | Application | Key Checks | |----------|-------------|------------| | DNV-OS-F101 | Submarine pipelines | Wall thickness, buckling | | API RP 1111 | Pipeline design | Pressure containment |
Configuration
Mooring Code Check
# configs/mooring_code_check.yml
code_check:
standard: "API_RP_2SK"
edition: "2015"
mooring:
lines:
- name: "Leg_1"
line_type: "Chain_R4_84mm"
mbl: 8500.0 # kN - Minimum Breaking Load
- name: "Leg_2"
line_type: "Chain_R4_84mm"
mbl: 8500.0
safety_factors:
intact:
static: 1.67 # API RP 2SK Table 2
dynamic: 1.82
damaged:
static: 1.25
dynamic: 1.43
load_conditions:
- name: "100-year intact"
condition: "intact"
load_type: "dynamic"
- name: "100-year damaged"
condition: "damaged"
load_type: "dynamic"
output:
report_path: "reports/code_check/"
format: "html"
Riser Code Check
# configs/riser_code_check.yml
code_check:
standard: "DNV_OS_F201"
edition: "2021"
riser:
name: "SCR"
material:
grade: "X65"
smys: 448.0 # MPa
smts: 531.0 # MPa
young_modulus: 207000.0 # MPa
geometry:
od: 0.2731 # m
wt: 0.0159 # m (wall thickness)
design_factors:
gamma_SC: 1.04 # Safety class factor
gamma_m: 1.15 # Material factor
gamma_F: 1.10 # Load factor
alpha_U: 1.00 # Material strength factor
checks:
- "hoop_stress"
- "longitudinal_stress"
- "equivalent_stress"
- "collapse"
- "propagation_buckling"
output:
report_path: "reports/riser_code_check/"
Python API
Mooring Safety Factor Check
from digitalmodel.modules.structural_analysis.capacity import CapacityChecker
def check_mooring_safety_factors(
max_tensions: dict,
mbl_values: dict,
standard: str = "API_RP_2SK"
) -> dict:
"""
Check mooring line tensions against MBL limits.
Args:
max_tensions: Dict of {line_name: max_tension_kN}
mbl_values: Dict of {line_name: mbl_kN}
standard: Design standard to use
Returns:
Dict with check results
"""
# Safety factors per API RP 2SK (2015)
if standard == "API_RP_2SK":
safety_factors = {
"intact_dynamic": 1.82,
"intact_static": 1.67,
"damaged_dynamic": 1.43,
"damaged_static": 1.25
}
elif standard == "DNV_OS_E301":
safety_factors = {
"intact_dynamic": 2.20,
"damaged_dynamic": 1.50
}
else:
raise ValueError(f"Unknown standard: {standard}")
results = {}
for line_name, max_tension in max_tensions.items():
mbl = mbl_values.get(line_name)
if mbl is None:
continue
# Calculate utilization
line_results = {
"max_tension_kN": max_tension,
"mbl_kN": mbl,
"checks": {}
}
for condition, sf_required in safety_factors.items():
allowable = mbl / sf_required
utilization = max_tension / allowable
passes = utilization <= 1.0
actual_sf = mbl / max_tension
line_results["checks"][condition] = {
"allowable_kN": allowable,
"utilization": utilization,
"actual_sf": actual_sf,
"required_sf": sf_required,
"passes": passes
}
results[line_name] = line_results
return results
# Example usage
max_tensions = {
"Leg_1": 2450.5,
"Leg_2": 2380.2,
"Leg_3": 2320.1,
"Leg_4": 2290.8
}
mbl_values = {
"Leg_1": 8500.0,
"Leg_2": 8500.0,
"Leg_3": 8500.0,
"Leg_4": 8500.0
}
results = check_mooring_safety_factors(max_tensions, mbl_values)
for line, data in results.items():
intact_check = data["checks"]["intact_dynamic"]
print(f"{line}: Utilization = {intact_check['utilization']:.2%}, "
f"SF = {intact_check['actual_sf']:.2f} "
f"({'PASS' if intact_check['passes'] else 'FAIL'})")
Riser Stress Check
from digitalmodel.modules.structural_analysis.capacity import CapacityChecker
import math
def check_riser_stress(
max_tension: float,
max_bend_moment: float,
internal_pressure: float,
external_pressure: float,
od: float,
wt: float,
smys: float,
standard: str = "DNV_OS_F201"
) -> dict:
"""
Check riser stress against allowable per design code.
Args:
max_tension: Maximum tension (kN)
max_bend_moment: Maximum bending moment (kN.m)
internal_pressure: Internal pressure (MPa)
external_pressure: External pressure (MPa)
od: Outer diameter (m)
wt: Wall thickness (m)
smys: Specified minimum yield strength (MPa)
standard: Design standard
Returns:
Dict with stress check results
"""
id_ = od - 2 * wt
area = math.pi / 4 * (od**2 - id_**2)
i_moment = math.pi / 64 * (od**4 - id_**4)
# Axial stress
sigma_a = max_tension * 1000 / area / 1e6 # MPa
# Bending stress
sigma_b = max_bend_moment * 1000 * (od / 2) / i_moment / 1e6 # MPa
# Hoop stress (thin wall approximation)
delta_p = internal_pressure - external_pressure
sigma_h = delta_p * (od - wt) / (2 * wt) # MPa
# Von Mises equivalent stress
sigma_e = math.sqrt(
sigma_a**2 + sigma_b**2 + sigma_h**2
- sigma_a * sigma_h - sigma_b * sigma_h - sigma_a * sigma_b
+ 3 * 0 # Shear assumed zero
)
# Allowable stress per DNV-OS-F201
if standard == "DNV_OS_F201":
gamma_SC = 1.04 # Normal safety class
gamma_m = 1.15
alpha_U = 1.00
sigma_allowable = smys * alpha_U / (gamma_SC * gamma_m)
else:
# API approach
sigma_allowable = smys * 0.67 # 2/3 SMYS
utilization = sigma_e / sigma_allowable
return {
"axial_stress_MPa": sigma_a,
"bending_stress_MPa": sigma_b,
"hoop_stress_MPa": sigma_h,
"von_mises_stress_MPa": sigma_e,
"allowable_stress_MPa": sigma_allowable,
"utilization": utilization,
"passes": utilization <= 1.0,
"standard": standard
}
# Example usage
result = check_riser_stress(
max_tension=1500.0, # kN
max_bend_moment=250.0, # kN.m
internal_pressure=25.0, # MPa
external_pressure=15.0, # MPa
od=0.2731, # m
wt=0.0159, # m
smys=448.0 # MPa (X65)
)
print(f"Von Mises Stress: {result['von_mises_stress_MPa']:.1f} MPa")
print(f"Allowable: {result['allowable_stress_MPa']:.1f} MPa")
print(f"Utilization: {result['utilization']:.2%}")
print(f"Status: {'PASS' if result['passes'] else 'FAIL'}")
Standards Lookup
from digitalmodel.modules.standards_lookup import StandardsLookup
# Initialize lookup
lookup = StandardsLookup()
# Search for relevant standards
results = lookup.search("mooring design")
for standard in results:
print(f"{standard['name']}: {standard['path']}")
# Get specific standard
api_2sk = lookup.get("API_RP_2SK_2015")
print(f"Standard: {api_2sk['title']}")
print(f"Location: {api_2sk['path']}")
Generate Compliance Report
def generate_compliance_report(
check_results: dict,
output_path: str,
project_info: dict
) -> str:
"""Generate HTML compliance report."""
html_content = f"""
<!DOCTYPE html>
<html>
<head>
<title>Code Compliance Report</title>
<style>
body {{ font-family: Arial, sans-serif; margin: 40px; }}
h1 {{ color: #333; }}
table {{ border-collapse: collapse; width: 100%; }}
th, td {{ border: 1px solid #ddd; padding: 12px; text-align: left; }}
th {{ background-color: #4CAF50; color: white; }}
.pass {{ color: green; font-weight: bold; }}
.fail {{ color: red; font-weight: bold; }}
</style>
</head>
<body>
<h1>Code Compliance Report</h1>
<h2>Project: {project_info.get('name', 'N/A')}</h2>
<p>Standard: {check_results.get('standard', 'N/A')}</p>
<p>Date: {check_results.get('date', 'N/A')}</p>
<h3>Summary</h3>
<table>
<tr>
<th>Component</th>
<th>Max Load</th>
<th>Allowable</th>
<th>Utilization</th>
<th>Status</th>
</tr>
"""
for component, data in check_results.get("components", {}).items():
status_class = "pass" if data["passes"] else "fail"
status_text = "PASS" if data["passes"] else "FAIL"
html_content += f"""
<tr>
<td>{component}</td>
<td>{data['max_load']:.1f}</td>
<td>{data['allowable']:.1f}</td>
<td>{data['utilization']:.1%}</td>
<td class="{status_class}">{status_text}</td>
</tr>
"""
html_content += """
</table>
</body>
</html>
"""
with open(output_path, "w") as f:
f.write(html_content)
return output_path
Safety Factors Reference
API RP 2SK (2015)
| Condition | Analysis | Safety Factor | |-----------|----------|---------------| | Intact | Quasi-static | 1.67 | | Intact | Dynamic | 1.82 | | Damaged | Quasi-static | 1.25 | | Damaged | Dynamic | 1.43 |
DNV-OS-E301
| Condition | Consequence Class 1 | Consequence Class 2 | |-----------|---------------------|---------------------| | ULS Intact | 2.20 | 2.50 | | ULS Damaged | 1.50 | 1.65 | | ALS | 1.00 | 1.10 |
ISO 19901-7
| Condition | Category 1 | Category 2 | |-----------|------------|------------| | Intact | 1.67 | 2.00 | | Damaged | 1.25 | 1.50 |
Best Practices
Before Code Check
- Verify simulation completed - Ensure full 3-hour run
- Check load cases - Cover all design conditions
- Validate inputs - Correct MBL, geometry, material
- Document assumptions - Record safety class, consequence class
During Check
- Use correct standard - Match project requirements
- Apply correct factors - Consider condition (intact/damaged)
- Check all components - Lines, connections, anchors
- Consider fatigue - Not just ultimate capacity
Reporting
- Clear presentation - Pass/fail for each check
- Utilization ratios - Show margin
- Reference standard - Cite clause numbers
- Recommendations - Action items for failures
Error Handling
try:
results = check_mooring_safety_factors(tensions, mbl_values, "API_RP_2SK")
except ValueError as e:
print(f"Unknown standard: {e}")
print("Supported standards: API_RP_2SK, DNV_OS_E301, ISO_19901_7")
except KeyError as e:
print(f"Missing data: {e}")
print("Ensure all lines have MBL values defined")
Related Skills
- orcaflex-post-processing - Extract results
- orcaflex-extreme-analysis - Find design loads
- structural-analysis - Structural capacity checks
- fatigue-analysis - Fatigue code checks
References
- API RP 2SK: Design and Analysis of Stationkeeping Systems
- DNV-OS-E301: Position Mooring
- DNV-OS-F201: Dynamic Risers
- ISO 19901-7: Stationkeeping Systems for Floating Offshore Structures
- Source:
src/digitalmodel/modules/standards_lookup.py - Source:
src/digitalmodel/modules/structural_analysis/capacity.py