Ultem(R)ate Bracket B2 (0.023 lbs, 0.481 cu in)

Last crawled date: 1 year, 10 months ago

Ultra lightweight bracket, one-piece design of only 0.023 lbs and a volume of 0.481 cubic inches. Further development of my Ultem(R)ate Bracket B1.

Using common 3D printing features to reduce mass of unstressed but thick parts (bosses).

Stresses all less than 4500 psi, singularity/stress riser in FE model (due to contact between bolt and bracket) calculated analytically to find correct contact pressure and Hertzian stresses. No optimisation needed: Preliminary sizing done using basic mechanical theory, verified using FEM.

The bracket can be printed without supporting structures. The elastic hinge allows for aligning the two halves during mounting on the launch vehicle. There's ample room foor tools to reach (NAS1104) bolts. Mass is reduced even further by using a 15% infill density in unstressed areas.

Extra loadcase: differential pressure of 14.7 psi on inside of infill volume to avoid breakup of bracket during ascent.

Please find all details on the calculations and read about the design considerations in the pdf file attached.

To illustrate the differences in stress distributions I've added a picture (of one of my other entries in the challenge, but the difference is the same in all entries) that shows stresses in a bracket with real contact between the bracket and bolt on the left, and bonded contact between the bolt an bracket on the right.

Kind regards,

Wilbert Engels