Pre-Tension in a Gridshell

How would you model pre-tension in a gridshell caused by bending members in Solidworks?

Apparently, Solidworks has the capability to model the pre-tension, by essentially replicating the bending process, which allows the user to start with this model;

Gridshell Beam Model

And bend it a prescribed amount, resulting in this:

Bent Gridshell Beam

It is worth noting that, while this beam is correctly matched to the height and length of a gridshell (calculated mathematically in Matlab), it is only constrained via prescribed displacement at the ends, but the capability exists to constrain several points along the beam, ensuring the final shape matches the desired catenary curve.

Now, can this method handle bolted connections?

Turns out Solidworks also does that pretty well. I started the test with a simple cross of two long beams, connected with the standard curved plate and bolt connection used previously. The result (note this one uses several prescribed displacements to ensure a slightly more accurate catenary shape) is shown below:

Basic Bolted Joint Bent

Which also started laid out flat:

Basic Bolted Joint Model

This model involved most of the same process as before:

1. Lay out the members flat
2. Use Assembly mates to achieve the desired position and layout
3. Fix the center of each beam (this leaves both plates able to flex)
4. Sketch lines into the beams to create the edges that will have prescribed deflections
5. Prescribe the deflections, making use of the "Split" option for selecting lines partway down the beam

Now, what if the bolted connection moves?

The next logical step was to see what happens if the bolted connection itself needs to move with the beam; how will Solidworks handle having the bolted connections moving like that? Will everything stay together as it should, or will the bolts do something unrealistic?

To test this, I started making a simple 5-member gridshell, in the shape of a catenary dome, as shown below modeled in Matlab:

Matlab 3-D Plot of 5-Member Catenary Dome

I haven't yet added all the members, but here is the flat assembly so far:

Unfinished Catenary Gridshell Laid Flat

It's hard to see, but each point where beams cross has a full bolted connection (bolted between two curved plates, that might have to change eventually to a more simple shape). The end of each beam was constrained to drop 2m vertically, so that everything ends up at "ground" level. The resulting model doesn't really look like a catenary shape (the next step is to use the Matlab model and constrain each joint to drop by the correct amount), but it shows that the bolted connections managed to hold up, even when the whole joint moves:

Unfinished Catenary Gridshell Bent

The next step is to add more complexity to this model to make it actually resemble the Matlab plot. In order to make the model match the plot, a few things must be added:

1. Add the other cross-beams, with 6 more bolted plate connections
2. Constrain each connection to displace its correct amount
3. If that still doesn't accurately resemble a catenary dome, then move on to prescribing the displacement of each beam at a few intermediate points