Every prediction is accountable to physical evidence.
MDC is not a black box. Every knockdown factor can be traced back to mechanistic models and compared against experimental collapse data. The methodology is published, the data is auditable, and the statistical basis is explicit.
Experimental records
Curated buckling test data from 60+ years of published research. Blachut, Seaman, Kaplan-Fung, Wiggins, DNV-GL, and more. Filter by geometry, load case, author, and failure mode. Where the database holds matching tests, MDC curves are overlaid against real collapse measurements — and every record is traceable to its source publication. MDC’s knockdown surfaces and plasticity correction are fitted to FE Monte-Carlo campaigns and checked against a curated database of 1,000+ comparison-ready collapse tests — each backed by a deterministically reproducible FEM recomputation, with full per-campaign statistics (see the auto-generated validation report). A few sub-models are anchored to published tests.
Published methodology
The MDC framework is published in the Proceedings of the Royal Society A (2025). Full derivation, full author attribution. The scientific foundation is transparent and independently verifiable — not a black-box fit.
Statistical basis
Results are available on A-Basis (p01: 99% survival, 95% confidence), B-Basis (p10: 90% survival), and Mean. Choose the basis that matches your certification requirement and regulatory context.
Collapse tests — physical buckling experiments curated in the Validation Hub (1,000+). Plasticity check subset — the 400+ collapse tests, a subset of the 1,000+, that the plasticity correction is checked against.
MDC vs. NASA SP-8007 vs. GMNIA/FEM.
Three routes to a buckling proof — and what each one costs you in practice.
| Criterion | MDC | NASA SP-8007 | GMNIA/FEM |
|---|---|---|---|
| Time to result | Seconds | Minutes (hand calculation) | Days to weeks |
| Conservatism & KDF basis | Regime-dependent, fitted to FE Monte-Carlo campaigns; conservatism quantified per curve (A/B basis selectable) | Single empirical design curve from 1968 — blind to why | Exactly as conservative as the imperfection you assume — the result is an analyst choice |
| Imperfection provenance | Measured imperfection shapes in the FE ensembles; the amplitude you enter, guided by measured data per fabrication class | Implicit — the imperfections of the 1960s test articles, not those of your fabrication | Analyst-defined (eigenmode, dimple, scan); must be justified case by case |
| Validation basis | 1,000+ curated experiments, cross-checked against full-scale launcher hardware where records are available | A design curve drawn below most of the 1930s–1960s test data; some of those tests fall below it | Per project — quality stands and falls with model and analyst |
| Required expertise | Design-engineer level: geometry, load case, material in — traceable KDF out | Low — one chart lookup, the same answer for every shell of that R/t | Nonlinear-FE specialist; days of modeling, meshing and imperfection studies per configuration |
What MDC delivers today — and what is still in development.
The MDC A-Basis and B-Basis are the statistical design allowables of the Pro tier. Released cells are checked against our test database. Anything outside the matrix below runs through referenced third-party methods (Eurocode, NASA, DNV, ECSS, GOST) where implemented — free registration covers NASA SP-8007 and EN 1993-1-6:2007, the full set comes with the Professional plan.
| Geometry | Axial Compression | Bending | Combined Bending + Compression | External Pressure | Torsion |
|---|---|---|---|---|---|
| Cylinder | ✓ MDC A & Bincl. plasticity & internal pressure | ✓ MDC A & Bincl. plasticity & internal pressure | ✓ MDC A & B | ✓ MDC A & Bincl. plasticity | ✓ MDC A & Blaterally restrained ends · incl. plasticity |
| Cone | ✓ MDC A & Bequivalent-cylinder approach · incl. plasticity & internal pressure | ✓ MDC A & Bincl. plasticity & internal pressure | ✓ MDC A & B | ✓ MDC A & Bincl. plasticity | — |
| Sphere | — | — | — | ✓ MDC A & Bincl. plasticity | — |
| Torisphere | — | — | — | ✓ MDC A & Bincl. plasticity | — |
Cone axial uses the equivalent-cylinder approach. Referenced third-party methods (NASA, Eurocode, DNV, ECSS, GOST) are available side by side only for their implemented geometry and load-case scopes. General availability follows with the SC2 release once the peer-reviewed methodology is published.
Quantify the margin your structures really have.
Size each wall with a knockdown for its own shell, with full traceability. Start in the free Preview mode — no commitment, no credit card.
Read the publication — Proc. R. Soc. A, 2025