Force vs Pressure Loadings

[huiying]

Hi,
I'm doing a structural analysis on a Wind Tunnel Model. Does anyone has any idea the percentage difference in applying sectional force loadings vs pressure distribution loadings?

Regards.

 

[Drej]

Absolutely no difference in load value. In FE, any pressure load is converted to force at the nodes anyway. The difference is that forces once applied follow the nodal coordinate system, while pressure loadings will always remain tangential to the surface applied.

Cheers,

-- drej --

 

[corus]

To correct Drej, I believe that pressure loadings will only always remain tangential to the surface if large displacement analysis is used. As was said, pressures are simply converted to nodal forces and always act in the nodal co-ordinate system when using small displacement analyses.

corus

 

[huiying]

Thanks Drej and Corus for your replies.

Perhaps I did not explain myself clearly. What I actually meant was that the forces loadings is a distribution along x-axis while the pressure loading is a distribution along x and y axes.

Example, for a tube axial along the x-axis
force loadings: for 0<x<1, the total force on that section is F1(N), for 1<x<2, total force = F2(N),....
pressure loading: for 0<x<1 and 0<y<1, pressure on that portion=P1(Pa), for 0<x<1 and 0<y<2, pressure=P2(Pa),....

What I would like to know is that for a cantilever kind of model, how different would the result be.
The force and pressure loadings are results from CFD analysis using the same conditions.

Regards.