Mechanical & Aerospace

Moment of Inertia Lab

The second moment of area is why beams are I-shaped, and it's where students fumble the parallel-axis theorem. Resize the flanges and web of an I-section and watch Iₓ, I_y, the centroid and the section modulus respond. You'll see directly that widening the flanges — putting material far from the neutral axis — buys far more stiffness than thickening the web.

centroid

3.36×10³ mm²

Area

11.64×10⁶ mm⁴

Iₓ

2.01×10⁶ mm⁴

I_y

161.60×10³ mm³

Sₓ (modulus)

Section height 144 mm. Section modulus Sₓ = Iₓ / c sets the bending stress σ = M / Sₓ — pair it with Beam Lab.

Flange width b_f100 mm
Flange thickness t_f12 mm
Web height h_w120 mm
Web thickness t_w8 mm

Watch how widening the flanges (mass far from the centroid) raises Iₓ far more than thickening the web — that's why beams are I-shaped.

How to use this simulation

The second moment of area is why beams are I-shaped, and it's where students fumble the parallel-axis theorem. Resize the flanges and web of an I-section and watch Iₓ, I_y, the centroid and the section modulus respond. You'll see directly that widening the flanges — putting material far from the neutral axis — buys far more stiffness than thickening the web.

Everything runs in your browser — no sign-up, no download. Change a value and the result updates instantly, so you can build a feel for how each input shapes the outcome. It pairs with Crameleon's practice exams and step sheets when you want to go from intuition to working the problems.