Optimal RIB structure for plastic plate stiffness

[BadBeta]

Hi,

I'm looking for the big lines about optimizing RIB structure for plastic plate stiffness. The plate is somewhat restricted along the edges, especially the corners, but I expect the middle of the sides to be relativly free to move inwards. Torsions stiffness is of less concern. The plate is quite large and rectangular.

Looking at different products with plates I've realized there are different philosophies around this - straight rib, diagonal ribs, round ribs and more exotic patterns. While we certainly will be doing some FEA to our design, I'd really appreciate any info about the big picture and phiosophical differences and advantages.

 

[BradJH]

I would really have to see your part to suggest a rib pattern. But X patterns generally work well. Make sure that the rib thickness is about 1/3 the thickness of the part wall. to reduce the appearance of "sink" witness in the part.