How To Calculate Bending Moment?

Short tutorial that explains you on how to calculate bending moment with BM formula and simple example calculation.

Bending Moment Formula and Calculation

Bending Moment is defined as the rotational force that occurs when a force is applied perpendicularly to a point at a given distance away from that point. It is calculated by mulitplying the perpendicular force by the distance from the point. A Bending Moment is simply the bend that occurs in a beam due to a moment. It is measured in terms of Nm. The hinge applies a clockwise (+) moment (torque) to the RHS, and a counter - clockwise ( - ) moment to the LHS.

In this short tutorial, let us discuss on how to calculate bending moment of the beam. The bending moment formula and calculation is given below.

Formula:
Bending Moment (BM) = Fr
Where,
F = Perpendicular Force
r = Distance

Bending Moment Calculation:
Step 1: Consider an example where the perpendicular force applied is 12KN, 6KN on the R.H.S and 6KN on the L.H.S on the beam of length 6m. How to calculate the bending moment?

Given,
Perpendicular Force = 6KN
Distance = 6/2 = 3m

Step 2: Applying values in the formula,
Bending Moment for R.H.S of beam,
BM = Fr = -6x3 = -18KN

Bending Moment for L.H.S of beam,
BM = Fr = 6x3 = 18KN

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