FEAStatic Study3D PrintingSheet MetalME 2500J

Murphy's Tank: Reinforced Frame

The printed chassis with its steel braces, set up as the assembly I ran a SOLIDWORKS static study on at 1000 N.

LOADING GEOMETRY · 0%

VIEWPORT · SHADED

The chassis is a printed PLA mid frame between two mirrored side frames. The leg-to-body corners of the side frames see the highest bending moment when the vehicle overhangs the gap, and on a printed part they sit right on the layer bond plane, which is the weak direction. The steel braces go across those corners.

I checked the frame with a static study in SolidWorks at 1000 N, standing in for a 100 kg stretch goal. The peak von Mises stress came out at 47.84 MPa against the 51 MPa horizontal yield strength quoted for printed PLA, a factor of safety of about 1.02. That was close enough to 1 that keeping the steel was an easy decision.

Cut a section through a side frame to see the brace sitting against the leg.

APPENDIX A // RENDERS & ANALYSIS

FIG.01 · Von Mises stress at a 1000 N load, peak 47.84 MPa — FIG.01 · VON MISES STRESS AT A 1000 N LOAD, PEAK 47.84 MPA

FIG.02 · Displacement from the same static study — FIG.02 · DISPLACEMENT FROM THE SAME STATIC STUDY

FIG.03 · Drawing sheet of the frame assembly — FIG.03 · DRAWING SHEET OF THE FRAME ASSEMBLY

PART OF PROJECTMurphy's Tank: Automatic Gap-Crossing Vehicle