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youarenotyourstuff t1_j8mq5tb wrote

Reply to comment by Arbiter51x in NASA's "evolved structures" radically reduce weight – and waiting by Maxcactus

Aerospace is completely different to building design.

In aerospace designs are custom out of necessity due to each part being highly mass optimized, interdependent on other parts and having different design goals and trade offs from project to project. Also, each part is highly validated and inspected as well as painstakingly assembled in (usually) very clean environments. The exact safety factor of the product is well known and controlled to a low ratio.

In building design, designs are using either commodity parts or commodity materials that are produced too much less exacting precision, often made on site exposed to the elements. So design knows the exact safety factor isn’t known and needs to be large to make up for this. There’s also always human lives at risk.

So building design rightfully has to be very conservative, regulated and has no impetus to change quickly. Aerospace design has to be less prescriptive and less safe just to make it to orbit. That doesn’t mean there’s not a ton of very good engineering involved in both fields, it just means more design freedom for aerospace.

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Arbiter51x t1_j8mrazc wrote

Is it possible to do design validation for designs like in the article?

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C-D-W t1_j8my5am wrote

I think the idea that most parts aren't already bespoke is a misconception. Everything structural on a rocket or space craft is bespoke. Only built for that craft. Maybe only built a handful of times. So that part is nothing new.

Validation for these designs would be no different than anything else. Finite Element Analisys (FEA) would be used first to evaluate the structure and any changes required to meet the specification would be made before prototyping.

However, what's neat about these procedurally generated parts is that it basically is FEA in reverse. Instead of doing design iteration from idea to part - you just tell it the specification and it designs a part that meets that out of the gate.

The only real downside is that you're much more limited on manufacturability. Either it can't be made using traditional methods and requires 3D printing. Or maybe it can be made on a CNC milling machine but it requires a 7+ axis machine center and takes 100x longer to make. Which for some parts might actually be fine, but for others the added cost would never make sense.

Really interesting topic I'd say.

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youarenotyourstuff t1_j8mu4yq wrote

Yes. These designs are basically highly optimized, non-uniform load structures. You validate their load capability the same way you validate complex parts designed by humans: finite element analysis (FEA).

Edit: FEA is how you validate before your first prototype is made. You also CNC or 3D print a prototype and physically stress it just like any other part. Design validation is NOT just done on paper. It also is done on prototypes made using non-production equipment / tooling.

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r_a_d_ t1_j8mymq6 wrote

FEA is actually part of the generation process... It's basically iterating different designs and validating many times. So the output of the process is already at least FEA validated. You would then do all the additional validation that you would typically do on a classically designed part as well.

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Portmanteau_that t1_j8oxlc0 wrote

It's the same in the medical field as well. Extensive V&V for any 'new' device, even if it's based on predicate devices. I think a lot of laypeople aren't aware of the quality and regulatory requirements already in place for industries like these.

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