@Ann: Although steel is stronger than aluminum, it's not really too surprising that forged aluminum wheels are stronger than steel wheels made from sheet metal -- the designs and manufacturing processes are completely different. A forged steel wheel would be much stronger than a forged aluminum wheel, but would also weigh a lot more. (Forged steel wheels make sense for railroad cars, but definitely not for on-road applications).
The lifecycle analysis is very interesting. It is very comprehensive, and all of the assumptions seem to be reasonable. It makes a convincing case.
Lou, you're certainly right about the recyclability of aluminum, and steel too to a somewhat lesser extent. But it's also true that LCA has to look at everything. In fact, the latest concept of the life cycle is "cradle-to-cradle", not "cradle-to-grave." CtoC includes that last link in the chain that closes the loop (to mix metaphors) of recycled material going back into the product.
Ann, you mention end of life phases when talking about the life cycle cost analysis. You mention recycling and disposal. Steel and aluminum of this type will certainly be recycled. It has been known for some time that aluminum recycling is extremely effecient. I think it uses about 5% of the energy to recycle aluminum as it does to refine it from bauxite. Steel is also effecient, although I am not sure of the ratio. Steel mini-mills are the most effecient steel mills becuase they use scrap. So, I assume in this case the wheels of both types will be recycled.
It is good, though to see such comprehensive analysis. If you are looking at full lifecycle costs, then you really have to look at everything.
How 3D printing fits into the digital thread, and the relationship between its uses for prototyping and for manufacturing, was the subject of a talk by Proto Labs' Rich Baker at last week's Design & Manufacturing Minneapolis.
How can automakers, aerospace contractors, and other OEMs get new metal alloys that are stronger, harder, and can survive ever higher temperatures? One way is to redesign their crystalline structures at the nanoscale and microscale.
Although a lot of the excitement about 3D printing and additive manufacturing surrounds its ability to make end-products and functional prototypes, some often ignored applications are the big improvements that can come by using it for tooling, jigs, and fixtures.
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