Column Buckling API

Euler column buckling as an API, computed locally and deterministically. The critical-load endpoint computes the Euler critical (buckling) load of a slender column, Pcr = π²·E·I / (K·L)², from the Young's modulus, the second moment of area, the length and the end conditions — pinned-pinned (K=1), fixed-fixed (K=0.5), fixed-pinned (K≈0.7) or fixed-free / cantilever (K=2), or a custom effective-length factor — and, given the cross-section area, also the radius of gyration, slenderness ratio and critical buckling stress. The section endpoint returns the area, the second moment of area about both axes and the radius of gyration for a solid circle, a hollow circle or tube, or a rectangle, and highlights the weak-axis value that governs buckling. The slenderness endpoint computes the slenderness ratio λ = K·L/r and, given the modulus and yield strength, the transition slenderness λ1 = π·√(2E/σy) that separates long Euler columns from short and intermediate ones, classifies the column and returns both the Euler and the J.B. Johnson critical stresses. Everything is computed locally and deterministically, so it is instant and private. Ideal for structural, mechanical and aerospace engineering tools, strut and frame design, machine-design and stability-analysis apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is column buckling and stability; for beam bending, shear and deflection use a beam-statics API.