Question

A cantilever beam of cross-section 90 mm. width 120 mm deep carries a UDL of 12 KN/m. over the entire length and a concentrated load of 15 KN at the right end. Find the bending stress in the beam, when the length of beam is 10 m. ​

Answer 1

Answer:

Ans is σ = 166.67N/mm2

Step 1: Data:

Length of beam = 2m or 2000mm

load at failure = 2KN

Section dimensions = 40mm X 60mm

Step 2: Calculation of moment of inertia

I = bd3/12

= (40) (603)/12

= 7.2X105 mm4

Step 3: Calculation of bending moment about fixed end

M = WL

= (2)(2)

= 4KN-m

Step 4:

Calculation of bending stress

M /I= σ / y

Substitute for above (where y = depth /2= 60/2 = 30mm)

There fore

σ = 166.67N/mm2