Why does it need to model the human brain?
I work with expert systems doing simulation for engineering analysis. There are experimental systems today that can actually engineer parts, through trial and error. They take a specification for a part or assembly, and start making parts. Do FEA on em, change em, do it again, over and over. Eventually they reach optimal designs that fit the specification and can even blow it away regarding weight, strength, cost to produce, etc. All with minimal human input. It just takes time and uses existing system designs and analysis procedures. These systems will be the norm in 5-10 years as the hardware to use them becomes more cost effective, as in they run in decent time frames. No "AI" (as in human analog) anywhere in sight. Systems like this can be used to do all sorts of things. No special advancements needed except faster computers.