GeniCAD

GeniCAD is a free mechanical CAD software with a built-in structural analysis module for beams or frames. Users can design mechanical parts or frames, apply loads, and see stress/deflection results. The modeling interface uses extrude, revolve, sweep, and fillet. GeniCAD also exports to STL or DXF. Though limited compared to full FEA, its basic solver helps small shops test feasibility. Suited for hobbyists or small contractors wanting no-cost mechanical design plus rudimentary structural checks.