Question

The rectangular cross section has width 0.1 m and height 0.3 m.

A beam is found to have a maximum bending stress of 4.4 MPa.

What is the magnitude of the bending moment in N-m?

Answer 1

solution Given. w = 0.1m , h = 0.3m N Gmax = A 4.4 MPa 4.48106 Pa bh3 consider a rectangular section of width is O'lm and height is 0.3m. let Na be the neutral axis. Then moment of inertia of the beam section & E = 12 the distance of the farthest point of the section from neutral axis 2= 6h3/12 Ymax 6 ch/2 bending moment M= 62 = 4.4x100x1.5x10 M = 66OON-M Ans. Y max = 1/2 I 6+2 _ 0.1% (0.3) 3 = 9.5x10 6 m3 -3