ME06 · Sem 4 · Structural analysis

Pratt truss

Aim: Analyse a Pratt truss and compare with the Warren truss.

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

🔬 Virtual lab

Starting the lab…

📘 Theory

In a Pratt truss the diagonals slope towards the centre so they are in tension and the verticals in compression, which suits steel (slender members buckle in compression).

Euler buckling: P_cr = π²EI/L²

🧰 Apparatus (virtual)

Model truss
strain gauges

📝 Procedure

Run and read the diagonal forces
Compare the maximum member force with ME05
Change the bar area and watch the stresses
Find members that could buckle

Observations and result (kept on this device)

🎤 Viva questions

Why does a Pratt truss suit steel

Long diagonals are in tension, which does not buckle.

What is a zero-force member

One that carries no load for a given loading.

🛡️ Safety

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