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Column Buckling (Euler)

🏗️ Civil · Critical buckling load, stress, and slenderness ratio calculation

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Pcr=π2EI(KL)2P_{cr} = \frac{\pi^2 EI}{(KL)^2}

Long, slender columns (compression members) can buckle sideways suddenly and unpredictably well before reaching their yield strength. Swiss mathematician Leonhard Euler’s 1744 work, the first mathematical explanation of this phenomenon, still forms the basis of elastic buckling analysis today.

The effective length factor (K) depends on the column’s end support conditions and converts the real length into “an equivalent pinned-pinned column length”:

  • Pinned at both ends: K = 1.0 (reference case)
  • Fixed at both ends: K = 0.5 (4× stronger)
  • Fixed-free (cantilever): K = 2.0 (4× weaker)

The slenderness ratio (λ = KL/r) determines the validity limit of the Euler formula. In steel columns, behavior above λ ≈ 90 is elastic buckling (Euler formula valid); below that, it’s inelastic buckling/yielding (different, separate formulas required — e.g. the Johnson parabola). This tool shows a warning when the slenderness comes out low.

✅ Verified

This tool's calculation logic has been checked against a hand-computed numerical verification test. Test source: src/lib/calc/burkulma.test.ts.

  • [2] Hibbeler, R. C.. Mechanics of Materials, 10 ed.. Pearson, 2017.
  • [21] CEN. EN} 1993-1-1 (Eurocode 3) — Çelik Yapıların Tasarımı: Genel Kurallar. European Committee for Standardization, 2005. (2014'te A1 değişiklik eki ile güncellendi (EN 1993-1-1:2005+A1:2014))

Results are for educational and preliminary-sizing purposes; final engineering design decisions must reference the relevant standards and a licensed engineer's approval.