3D frames

protontim

I would like to know if I can use the beam element, or some other element, to create a 3D frame and load it. Is there an example of this somewhere? I see a single beam element being loaded, but I would like to simulate a frame.

Thanks,
Tim

Victor

Hello Tim

Yes, you can do that. Simply connect the elements together and they'll transmit moments as well as forces between each other. Here's an example of a 3D frame structure.

For non-symmetric cross-sections, you'll also need to define the orientation of each element in the Element properties dialog box (right click an element or selection of elements).

protontim

Hi Victor,

That looks really good. Two questions if I might.
1) How do I find maximum stress (like vonMises) in the frame?
2) Is there a section in the tutorial that shows me how to construct a structure out of individual elements? What I am looking for is a tutorial that would show me what I need to know to build a frame with beam elements.

Thank you very much - great product.
Tim

Victor

1) The longitudinal stresses (caused by bending and tension, not shearing or torsion) are shown at 4 points on the section of each beam. These are listed in the outline tree as Longitudinal Stress Point 1, etc. Click the plus next to any one of those and choose "Element values" to turn off node averaging. The color key then shows the maximum and minimum of all 4. To find where that maximum occurs, you may need to look for it visually.

2) Section 2.6 of the Tutorials manual "Dynamic Response of a Crane Frame" shows a way to create a 2D frame mesh. for 3D, just do the same types of operations with different coordinates. You can also place or moving nodes with the mouse (using Mesh tools -> Create -> Node... and -> Element... . In this case, rotate the view as needed because they move only in the plane of the screen. This allows arbitrary 3D positioning.

protontim

Thanks. I got it working. I had to merge nodes at my junctions to make things work correctly but I am good to go. Thanks again.