Weld fatigue life, dynamically loaded (Eurocode 3, prEN 1993-1-9)
Constant-amplitude fatigue limit, cut-off limit, S-N slope exponent and fatigue life of a dynamically loaded weld detail, from its Eurocode 3 detail category (FAT class) and applied stress range.
For ΔσR below the cut-off limit ΔσL, the legacy source never assigns m/NR before referencing them (a coding bug — see module header) and would throw an uncaught ReferenceError in a real browser session, so the "infinite life" branch never actually reports anything there. This port returns NaN for m/NR in that regime rather than "infin", and is golden-tested only for ΔσR >= ΔσL, matching what the original can actually execute without crashing.
Method & references
- Eurocode 3: Design of steel structures, Part 1-9: Fatigue, prEN 1993-1-9:2003 — two-slope S-N curve for weld details.
- Despite sharing an identical page <title> with lapjoint.htm, this source is a genuinely distinct model (confirmed by reading both sources) — see lap-joint-shear-stress.ts header for the sibling analysis.
The computation is a literal port of the original client-side JavaScript from /calculators/c3_7.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.