Shear Area

[byron86]

I have a custom angle section,  how is robot determining the shear areas?

according to BS5950,  its the longest leg of concerns area*0.9.  So im confused how its getting its values. Secondly, why is there an alpha value.

Thanks

[byron86]

Ag the units confused me.  So its determined the principal axis but again how does it calculate the shear areas for the orientated axis?

[Artur.Kosakowski]

By integration of shear stresses.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[byron86]

okay is there a way to check this?

[Artur.Kosakowski · Accepted solution]

1. Apply a shear force in the given direction

2. Check stress distribution in a cross section (stress analysis map)

3. " Slice a profile into straps perpendicular to the direction of shear force and assume values of stress for each of them

4. Sum up such obtained stresses and divide by applied shear force

In general the steel design module calculates shear areas on its own following the selected design code provisions. 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[byron86]

So just to confirm.  You determine an average stress for the entire profile.  then Force/(average Stress)= Shear Area

Okay thanks, its trickey for angles but the code would just take each leg parallel to the direction and use just that area, however due to alpha angle I guess distributes more stress and creates a greater shear area.

[Artur.Kosakowski]

[zepedroboal]

Could you tell me what the letters mean? Is Q the first moment of area? If so, in my case i have a symetric H-section, does that mean that it's only from half of the section? Is G the distortional module - 80 GPa right?

[Artur.Kosakowski]

Is Q the first moment of area

It is a shear force

Is G the distortional module - 80 GPa right?

Correct.

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.