Generation ship design project

[AstroChara]

...it appears that unless you use a generous amount of the very best shielding material humanity has to offer, you would have little luck surviving a short trip against the normal dust that exists everywhere.

That really depends on the speed of travel. At what speed does dust become a significant problem that a well-designed shield can't handle?

Gotta admit we’ve only been assuming solid slabs of materials at the moment, but I was tinkering with a calculator my friend (with help from Luke Campbell) developed, and at 0.1c, a 1 metre thick slab of “graphite” (I assume this is a workable stand-in for carbon allotrophs and such that don’t shatter as easily) would survive for 16 light-years. Most materials last for a lot less. It seems the important property here is yield strength - more yield strength to reduce erosion rate. At 0.2 ly that drops to 3.9 ly. Also you presumably want the actual shield to have some redundancies for cases where your ship gets struck by larger than usual particles.