| name | structural-analysis |
| version | 1.1.0 |
| category | engineering |
| description | Structural analysis for marine and offshore structures per DNV/API/ISO codes. Use when performing ULS/ALS limit state checks, column buckling, beam deflection, tubular joint capacity (DNV-RP-C203), or stiffened panel analysis. Covers section properties, combined loading, and ALS dented pipe assessment.
|
| type | reference |
| tags | ["structural","mechanics","dnv","buckling","uls","als","beam-theory","stress-analysis"] |
| created | "2026-01-06T00:00:00.000Z" |
| updated | "2026-03-08T00:00:00.000Z" |
| requires | [] |
| scripts_exempt | true |
Structural Analysis Skill
Expert structural analysis for marine and offshore structures — ULS/ALS
limit state checks, buckling, DNV/API standards, tubular members, stiffened
panels, combined loading.
See references/standards.md for: full calculation examples, design criteria
details, structural member tables, load case matrices, design check formulas,
material property tables, safety factor tables, design workflow skeleton, and
code compliance report template.
When to Use
- Perform ULS (Ultimate Limit State) and ALS (Accidental Limit State) checks
- Analyze buckling of columns, beams, and stiffened panels
- Calculate section properties and stress distributions
- Apply DNV structural design standards
- Evaluate combined loading (axial + bending + torsion)
- Design tubular members and jacket structures
- Integrate fatigue analysis with structural checks
Core Knowledge Areas
1. Section Properties
Key shapes: circular tube, rectangular hollow section (RHS), I-beam/H-beam.
All return SectionProperties(area, Ix, Iy, J, Zx, Zy, rx, ry).
Full implementations: references/standards.md §Section Properties.
Circular tube shorthand:
A = π/4·(D²-d²), I = π/64·(D⁴-d⁴), r = √(I/A)
2. Stress Analysis
Combined loading stresses (axial + bending + torsion + shear):
- Axial:
σ = N/A
- Bending:
σ = M·y/I (or M/Z at extreme fibre)
- Torsion:
τ = T·r/J
- Von Mises:
σ_vm = √(σ²+3τ²)
Principal stresses via Mohr's circle. Full code: references/standards.md.
3. Column Buckling
Euler critical load: P_cr = π²EI/(KL)²
DNV check (DNV-OS-C101 / DNV-RP-C201):
- Reduced slenderness:
λ̄ = (KL/r)·√(fy/E)/π
- Buckling factor χ using European column curve 'a' (α=0.21 for welded tubes)
- Design resistance:
N_b_Rd = χ·A·fy/γ_M
- Unity check:
N_Ed / N_b_Rd ≤ 1.0
4. Beam Bending and Deflection
Simply supported: point at centre δ = PL³/(48EI), UDL 5wL⁴/(384EI).
Cantilever: point at free end δ = PL³/(3EI), UDL .
Allowable: L/360 (general), L/180 (cantilever).
