Question 26.19: The thin-walled composite beam section of Example 26.15 carr......

The thin-walled composite beam section of Example 26.15 carries a vertical shear load of 2kN applied in the plane of the web. Determine the shear flow distribution.

Step-by-Step
The 'Blue Check Mark' means that this solution was answered by an expert.
Learn more on how do we answer questions.

From Ex. 26.15 and Fig. S.26.19 the second moments of area are

\begin{array}{l c r}{{I_{X X}^{\prime}=2.63\times10^{10}  \mathrm{Nmm^{2}}}}\\ {{I_{YY}^{\prime}=0.83\times10^{10}  \mathrm{Nmm^{2}}}}\\ {{I_{X Y}^{\prime}=1.25\times10^{10}  \mathrm{Nmm^{2}}}}\end{array}

In this case S_{X}=0,S_{Y}=2\,\mathrm{kN} so that Eq. (26.69) becomes

q_{s}=-E_{Z i}\left[\left(\frac{S_{X}I_{X X}^{\prime}-S_{Y}I_{X Y}^{\prime}}{I_{X X}^{\prime}I_{Y Y}^{\prime}-I_{X Y}^{2}}\right)\int_{0}^{s}t_{t}X\,\mathrm{d}s+\left(\frac{S_{Y}I_{Y Y}^{\prime}-S_{X}I_{X Y}^{\prime}}{I_{X}^{\prime}I_{Y Y}^{\prime}-I_{X Y}^{2}}\right)\int_{0}^{s}t_{i}Y\,\mathrm{d}s\right]            (26.69)
q_{s}=-E_{Z,i}{\biggl(}-4.03\times10^{-7}\int_{0}^{s}t_{i}X\,\mathrm{d}s+2.68\times10^{-7}\int_{0}^{s}t_{i}Y\,\mathrm{d}s{\biggr)}

On the top flange, X=50-s_{1},\,Y=50~\mathrm{mm},\,E_{Z,i}=50~000~\mathrm{N/mm}^{2}. Eq. (i) then becomes

q_{12}=+40.3\times10^{-3}\int_{0}^{s_{1}}\left(50-s_{1}\right)\!\mathrm{d}s_{1}-26.8\times10^{-3}\int_{0}^{s_{1}}\!\mathrm{d}s_{1}

which gives

q_{12}=-0.02s_{1}^{2}-1.99s_{1}

When s_{1}=50~\mathrm{mm},~q_{2}=-149.8~\mathrm{N/mm}

In the web, X=0,\,Y=50-s_{2},\,E_{Z,i}=\,15\,\,000\,\,\mathrm{N/mm^{2}}. Eq. (i) then becomes

q_{23}=-8.04\times10^{-3}\int_{0}^{s_{2}}(50-s_{2})\mathrm{d}s_{2}-149.8

so that

q_{23}=0.40s_{2}+4.02\times10^{-3}s_{2}^{2}-149.8

When s_{2}=50~\mathrm{mm},~q_{23}=-159.5~\mathrm{N/mm}

s.26.19

Related Answered Questions