Frequently asked questions

SP-8007 gives a single empirical lower bound fitted to test data from the 1960s. Skalnav's MDC approach derives knockdown factors mechanistically from geometry, imperfection measures and buckling regime — and shows you the experimental evidence behind each curve. You can display both side by side in every analysis.

Skalnav computes and documents knockdown factors alongside nine established design codes, with full traceability of the underlying evidence. Whether a mechanistic KDF is admissible as the primary basis of a proof depends on your project's verification plan and approval authority — that decision always stays with them. Many teams use Skalnav today to justify margins, quantify the conservatism of code values, and cross-check their primary method against the experimental record.

Statistical bases for the design curve, analogous in spirit to material allowables: alongside the mean (best-estimate) curve, Basis B is the empirical 10th percentile of the underlying Monte-Carlo ensemble (conservative) and Basis A the empirical 1st percentile (highly conservative). They are quantile-based conservative approximations — not strict MIL-HDBK-5 tolerance limits — and the methodology notes state this explicitly. You choose the basis to match your project's reliability requirements.

From six decades of published collapse experiments — 1,000+ curated records in the ValidationHub with documented provenance for every data point, measured values strictly separated from assumed bounds.

Geometries: cylinders, cones, spherical shells (shallow cap through complete sphere), torispherical heads, and cone–cylinder assemblies; ellipsoidal and toroidal shells are available through the NASA SP-8032 module. Plain, sandwich and stiffened wall construction (ring frames, stringers, orthogrid).

Load cases: axial compression, global bending, torsion, transverse shear, external pressure and wind, plus combined cases (axial + bending, axial or bending + internal pressure, axial + external pressure, torsion combinations) and dedicated silo and tank workflows.

Not every combination carries a native MDC curve yet — where it doesn't, the nine implemented design codes cover the case. The authoritative, always-current view is the coverage matrix.

On-premise and air-gapped deployment is on our enterprise roadmap and evaluated per engagement — contact us to discuss requirements, availability and timelines.

The platform is hosted on servers located in Germany (IONOS SE) under a data processing agreement; all assets are served self-hosted — no third-party CDNs or trackers. Details, including your rights and retention periods, are in the privacy policy.

Yes — watch the demo, download the sample verification report, or open Skalnav directly in your browser: cylinder axial and bending work without a login.