Generating wind load on a space frame?

Replies to This Discussion

Permalink Reply by Karamba3D on July 1, 2012 at 12:00pm

You can either use the mesh-load-component or uniformly distributed beam loads.

Permalink Reply by djordje on July 1, 2012 at 3:20pm

What does "Pos" input at "Mesh-Load" component represent?

List of points on Mesh? How do I input them?

And why do I even need them? I though I only need to apply a uniform load intensity (that is the value of the particular vector) onto a mesh.

Permalink Reply by Karamba3D on July 2, 2012 at 12:35am

'Pos' expects the coordinates of nodes of the structural model where the equivalent loads from the surface loads shall act. Read the manual for details.

Permalink Reply by djordje on July 2, 2012 at 6:25am

That means "Pos" requires the same input of points (nodes) as "V" input of the "Create mesh" component?

Still something is wrong, as my resultant is 0.

Can you please take a look at the definition?

I consulted the manual and did not find an answer to this.

Thank you.

Attachments:

• mesh_load.gh, 6 KB
• mesh_load.3dm, 209 KB

Permalink Reply by Karamba3D on July 2, 2012 at 7:49am

The quad you defined consists of points that lie on a line - therefore it has zero area.

Take the full mesh it works.

Attachments:

• mesh_load_1.gh, 6 KB

Permalink Reply by djordje on July 2, 2012 at 10:10am

Thank you Karamba.

So in case I would like to check the wind load on the curtain wall construction of a free form building: I need to use the "Mesh" command from Rhino to convert my surfaces (curtain wall) from Surface to Mesh. And then apply that newly created mesh from Rhino to a parameter "Mesh" in this Grasshopper definition.

At the end I need to apply the supporting points for the curtain wall cladding, as points into the "Point" parameter in this Grasshopper definition.

Or am I wrong?

Attachments:

• mesh_load_3.gh, 7 KB
• mesh_load3.3dm, 219 KB

Permalink Reply by Karamba3D on July 2, 2012 at 12:01pm

The mesh for defining the meshload need not contain the points where the surface load is to be transferred to. You could also define a flat mesh that corresponds to the outlines of your building some distance away from it. This makes it easier to have wind blowing from different directions.

The real wind load would have a non-uniform distribution on the building which depends on its shape: pressure at the windward side, suction at the sides and at the leeward side. A uniform distribution however will be a reasonably good approximation.

Permalink Reply by djordje on July 2, 2012 at 1:52pm

As I did not understand you, does that "need not" also means that the upper solution is not correct, or just that it can be used, but it is not necessary to be that complicated?

Permalink Reply by Karamba3D on July 2, 2012 at 2:06pm

Yes. Try out both solutions and see in what respect they differ.

Permalink Reply by djordje on July 2, 2012 at 2:14pm

Thank you for the reply.

I did not understand the one you described.