Bending moment (N·m) — internal moment causing stress via σ = M·y/I. Larger moment increases stress linearly. Example: 5000 N·m for a typical beam.

M is required

Distance from neutral axis (m) — farthest fiber distance from center. Larger y increases stress. Example: 0.10 m for a 0.2 m beam.

y is required

Second moment of area (m⁴) — beam stiffness property. Larger I reduces stress. Example: 0.00010 m⁴ for a rectangular section.

I is required