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

scene 9 of 14

The value of $Q$ for point $H$ is the sum of these two portions:

Q = 42, 000 + 43.875 = 85, 875 m m^{3}

τ_{x y} = \frac{V Q}{I t}

For the orange regions, the first moment of area $Q$ is:

= 42, 000 m m^{3}

For the purple region, the first moment of area $Q$ is:

= 43, 875 m m^{3}