Sometimes using SolidWorks Simulation with weldments can be an interesting experience. Oftentimes there are more than just structural tubes in the model; plates, made by extruding sketches, co-exist with the weldment members and are used for items such as gussets or feet. SolidWorks Simulation allows, in a mixed mesh, for solid, shell, and beam elements. Creating the element groups themselves is not a difficult task and falls outside of purposes of this blog. I'd like to show you what you can do and what not to do when using mixed meshes and your SolidWorks weldments.
It is very important to understand the degrees of freedom each element type allows for. Solid elements only permit translational DOFs while shells and beams permit rotational in addition to translational. Having said that, when a solid and a beam or a solid and shell or a beam and a shell need to exist together, special bonding is required. Take for example the following image of a portion of a tube frame with a foot pad and a gusset (modeled as a plate).View this photo The gusset falls on the mid-line of the tube width and would be welded to the vertical and horizontal tubes. When meshed, it looks like the following image.
You may be tempted to locally bond the thickness face (or midsurface edge if using shells) of the gusset to the "beam" of a structural member. But this is not possible as beams are 1-D elements and shells and solids are not. There is no "place" for the software to provide the bonding. And so, for this case, the structural members will have to be meshed using solids or shells. (local bonded contacts will still be needed for shell-to-solid meshes)
Another case, as seen in the next image, is where the plate gusset is welded to the outside faces of structural members. In this case, while you still need local bonded contacts, the FACE of the gusset can be bonded to the beam.View this photo
You can see the image of the mesh here to the right.
Lastly, as seen with the footpad solids and beams also need local bonded contacts. Here however, instead of selecting the beam one needs to select the Joint (not the beam) and the top face of the footpad. Armed with these helpful hints, I trust you will be better equipped to tackle your next Simulation project with SolidWorks weldments and gussets.
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