Ultem(R)ate Bracket C1 (0.018 lbs, 0.376 cu in)

grabcad

Set of ultra lightweight brackets of only 0.018 lbs and a volume of 0.376 cubic inches together. Total mass can be reduced to 0.016 lbs but that would result in an unstable part to 3D print and a violation of the edge distance requirements.Using common 3D printing features to reduce mass of unstressed but thick parts (bosses).Basically two mirrored parts. Only needs 2 bolts to connect to launch vehicle.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. For comparison I've added a picture showing differences in stress distributions caused by real contact between the bracket and bolt, left, and a fixed bore hole ("bonded contact between bracket and bolt) on the right.Kind regards,Wilbert Engels