Answer to Question #170805 in Mechanical Engineering for John

Question

A perfect rectangular prism is on top of a beam. The beam has two supports on each corner. The cross section of the beam is a circle (d = 7.05 cm).

Solid Steel box: length = 1.45 m , weight = 9000 N.

Length of beam = 1.45 m

What is the max normal compressive stress on the beam?

Answer 1

S = $\pi$ r³/4 = $\pi$ d³/32 = 3.14 x (0.0705 m)³/32 = 3.44 x 10^-5 m³

$\sigma$ = My/I = 900 N x 1.45 m x 1.45 m / (3.44 x 10^-5 m³ x 1.45 m) = 37.9 x 10⁶ N/m² = 38.0 MPa