MecMovies 4.0 : M15.3: Principal Stresses in a Rectangular Tube Beam

scene 8 of 14

Use the flexure formula to compute the normal stress at point $H$ , located $40 m m$ below the $z$ centroidal axis.

σ_{x} = - \frac{M y}{I} = - \frac{(7 k N - m) (- 40 m m) (1, 000 N / k N) (1, 000 m m / m)}{15.224 \times 10^{6} m m^{4}}

= - 18.39 M P a

(compression normal stress)

Note: $I_{z} = \frac{(100 m m) (200 m m)^{3}}{12} - \frac{(90 m m) (190 m m)^{3}}{12} = 15.224 \times 10^{6} m m^{4}$