With the continuous increase in fuel costs and the increase of commute time, customers want to get higher mpg, and gasoline mileage is usually the key factor when buying cars.
In addition, current U.S. regulations stipulate that by 2025, the average fuel economy standard must reach 54.5 miles per gallon, 60 percent higher than the 35.5 miles required.
One potential way to make fuel-efficient vehicles is to make lighter vehicles. Reducing vehicle weight by 10 percent can increase fuel economy by 6 to 8 percent, according to doe. Carbon fiber composite is one of the most promising lightweight materials systems, which can replace heavy steel on automobiles.
In addition to being lighter, carbon fiber composites also provide engineers with more design freedom than traditional materials, enabling them to produce different shapes and structures. However, carbon fiber composites are not without challenges.
The properties of the materials are more complex than that of metals, because carbon fiber composites depend on complex characteristics, such as fiber load and fiber length distribution and fiber orientation that occur in the material due to the manufacturing process. Testing is also a challenge, said Leonard Fifield, a materials scientist and research director at the PNNL.
"Carbon fiber composites are very different from metals because they are not used in the entire component?? The material, instead, is made up of a mixture of different materials, "Fifield said“ One of the challenges of traditional testing of carbon fiber composites is extrapolation of test sample results. If you are making steel, maybe you can?? To test a small steel sample, you can know the expected values for the entire part. But when you have
Carbon Fiber Reinforced composite parts, different locations in the parts may have different properties. So if you just take a test sample, it may not represent the entire part of the property“
Due to this challenge, parts must be molded, manufactured and tested to understand performance. The industry and academic expert team led by Fifield and others at PNNL is working to address these issues and develop predictive engineering tools for the design of new, economical and lightweight automotive composites.
