The cost equation

At the end of September, we here at CT hosted the CompositesWorld Expo 2009 in Schaumburg, Ill. As usual, our conference gurus Scott Stephenson and Ralph Jessie put together a robust keynote speaker lineup that featured, among others, Jim deVries, staff technical specialist and manager of the Manufacturing Research Dept. at the Ford Research Laboratory, and Dr. Habib Dagher, director of the AEWC Advanced Structures and Composites Center at the University of Maine (to see our CW Expo report, click on the link under "Editor's Picks," at right).

DeVries talked about the prospects for increased carbon fiber use in cars. He suggested that the best use of carbon fiber in cars might be via sheet molding compound (SMC), but only if the cost of raw carbon fiber comes down to $5/lb. As it stands, he said, the current cost per pound of weight saved with carbon fiber SMC ($10.60) does not come close to that for aluminum ($1.00) or fiberglass SMC ($3.33). Even if carbon fiber comes down to $5/lb and a fabrication process is developed that can cost-effectively produce 200,000 units or more per year, he doubted that manufacturers of raw carbon fiber would be able to reliably provide enough fiber for the 75 million lb of carbon SMC that the auto industry would consume annually.

This is sobering. If carbon fiber SMC is ever to find a significant home in production vehicles — especially in body panels — it has to buy its way in, and it’s clear that the Fords of the world are watching material price points closely. I wonder, though, if hurdles for carbon fiber are that high: How close is the industry to a high-speed carbon fiber process to produce body panels? Are body panels on vehicles expected to provide structural support to a vehicle, and if not, then how does that change the product development equation? Finally, does it make sense, and is it fair, to simply replace metal parts with similar parts made with carbon composites? With the automotive industry shifting so many paradigms of late, this seems like a good time to reconsider automobile design to optimize components for composites.

In the infrastructure market, the cost equation appears to be shifting in favor of composites, as revealed by Dr. Dagher during his keynote. Dagher helped develop the “bridge in a backpack” composites technology at the Advanced Structures and Composites Center (see "Bridge cost cut with inflatable arches," under "Editor's Picks"). He reported that this technology is now competitive on a first-cost basis with concrete and steel. This is important because for years composites have had to be “sold” into infrastructure applications on the basis of valid, but too-easily-ignored true-cost calculations, derived from lifecycle analysis that factors in the composite’s extended service life and low maintenance. Further evidence of this competitiveness can be found in this issue, as well. Our “Engineering Insights” feature this issue (see "Tough I-beam bridge for tank traffic," under "Editor's Picks") highlights a thermoplastic composite bridge developed to support military vehicles.

As the Ford data show, it might be a little early to declare all composites so competitive, but it’s encouraging to see glass and carbon fiber considered for their durability, strength, light weight and thrift.