When you create structural member features, the software automatically names them based on the type and size of the structural members you insert.
The naming convention is Type Size(n), where n is the suffix that indicates the number of identical instances of the feature.
For example, if you insert four rectangular tubes with the size 3 x 2 x 0.25, the structural member that defines them is named rectangular tube 3 x 2 x 0.25(4).
When you hover over a structural member feature in the graphics area, the tooltip uses the same naming convention:
This naming convention applies to weldments created in SOLIDWORKS 2016 and later.