ME01 · Sem 3 · Strength of materials

Simply supported beam: centre point load

Aim: Find the deflection and bending stress of a simply supported beam and check it against theory.

🧪 Live simulation🧊 Real-time 3D bench⚠ Simulated values, not physical measurements

🔬 Virtual lab

Starting the lab…

📘 Theory

A beam carries load by bending: the top fibres are compressed and the bottom stretched. For a central load the bending moment peaks at mid-span (PL/4) and the deflection there is PL³/48EI. The FEA divides the beam into 24 frame elements.

δ_max = PL³/(48EI) · σ = M·c/I · I = bh³/12

🧰 Apparatus (virtual)

Steel beam 60 × 120 mm
two supports
loading hanger
dial gauge

📝 Procedure

Read the FEA maximum deflection and the hand-formula value
Move the load away from the centre and watch the shape change
Increase the section depth and see the deflection fall with h³
Find the load that brings the factor of safety to 2

Observations and result (kept on this device)

🎤 Viva questions

Why does doubling the depth cut the deflection by 8 times

I grows with h³.

Where is the bending stress zero

At the neutral axis.

🛡️ Safety

Virtual by default. Machine shops, CNC, presses and test rigs need instructor supervision, PPE and machine-specific safety training.