# Problem from Aircraft Structures for Engineering Students - 5ed

1. Jan 11, 2014

### mobilesystem

Hello to all ,

I need your help again , if you can .

My question is about a problem / exercise book solved Aircraft Structures for Engineering Students - 5ed , example 20.4 .

So the problem this section supports a vertical load of 10kN and the objective is to calculate the flow section in FIG .

The areas of booms are: B1 = B8 = 200mm ^ 2 B2 = B7 = 250mm ^ 2 B3 = B6 = 400mm ^ 2 B4 = B5 = 100mm ^ 2

http://imageshack.us/photo/my-images/811/0u2h.jpg/

Solving we have:

The shear flow is given by :

http://imageshack.us/photo/my-images/35/f5m4.jpg/

But given that the section is symmetrical , the value of Ixy = 0 and as we have no strength x then Sx = 0, so the expression is :

http://imageshack.us/photo/my-images/853/a1fe.png/

And Ixx = 13.86 * 10 ^ 4 ^ 6 mm

The above equation becomes:

http://imageshack.us/photo/my-images/577/v8dd.png/

Cutting the bar in section 23 , we can calculate the shear flow in the sections :

http://imageshack.us/photo/my-images/690/vrtl.png/

And now we have a serious problem :

I do not know how to calculate the moments that appear in the image below :

http://imageshack.us/photo/my-images/841/24i6.png/

The expected value of qs , 0 result is : qs , 0 = -5.4N/mm in the counterclockwise direction , as can be seen in the image below .

http://imageshack.us/photo/my-images/20/dzgi.png/

Things to know :
The value of 97200 refers to the internal area of ​​the figure :
The 2 refers to the symmetry of the bars and the rest do not know .

All help is welcome.

Hug and Thanks