Nasa hand rail from argentina

Last crawled date: 1 year, 11 months ago

Ok, I finally had time to continue with the design, it is still a work in progress but much closer to the final design.
As you can see, it is quite intricate, but that's not a problem for 3D printing, and this is the explanation why the complexity of the design:

-First, Meets all requirements of the challenge, both in shape, size, dimensions, not elements such pins or bolts are needed very little support is required for printing and no special tools are required. (on this point have some doubts, since it is necessary to remove the support material in any way and can not be done by hand. My greatest concern are the particles and chips that may be loose in space microgravity).

-Second, The lever mechanism is to ensure rapid assembly and disassembly, and a secure fit that does not allow the movement of the clamp along the rail.

-Thirdly, the complexity of the geometry, it is because I paid special attention to that there are no tensile stress in the printing z axis or shear stresses in the xy plane.
Some time ago I conducted a study of the behavior of 3D printed parts according to ASTM D638 Tensile Strength Plastic Test. My conclusions were that the printed pieces in 3D with FDM technology, do not take load in the axial direction of the printing (Z), it was not possible for me not even take a reference value for this type of load.
On the other hand, I managed to see that besides the orientation of the direction of printing, the amount of solid layers in the wall of the piece is what most influences the ultimate strength of the piece. The fill percentage practically does not change the value.
It is because of this that it is very difficult to to perform a FEA since the printed piece behaves in a very anisotropic way.

Here is the video on youtube of tensile tests of 3D printed probes.
http://youtu.be/zXoISmNSXQ4

I already machined a handrail sector according to specified dimensions, the next step will be print a clamp to check interference, fits, dimensions, etc. and modify the interface according to the seat trak stud, and then upload the final design.

I hope to have time to do some actual strength tests of the final design, gripped to the rail and check how close my design is to the reference values for the aluminum clamp.

Hope you like it!