by Susan I. Hill, Group Leader – Structures and Material Evaluation Group, Structural Integrity Division, University of Dayton Research Institute
New Tensile Test Standard for Filled Polymers in Development, We Need Your Help to Go Forward!
The automotive lightweighting landscape is continually changing and growing as carmakers strive to produce more efficient vehicles that adhere to strict U.S. government Corporate Average Fuel Economy (CAFE) standards. However boosting efficiency isn’t the only challenge. In shedding pounds to increase miles per gallon (kilometers per liter), the auto industry must also maintain vehicle safety for drivers and passengers. No small feat. Achieving this comes down to material choices – specifically we are thinking advanced plastics and polymer composites, am I correct?
Plastics are lightweight by nature, and by themselves can be quite strong. However, as you know, there are ways to make plastics even stronger, by reinforcing the matrix material with various fibers, including chopped or continuous filaments, rovings, or fabrics of natural fiber, fiberglass, carbon fiber, basalt fiber, or even nanofibers. Like rebar in a cement pillar or the weave of threads in cloth, reinforcing resin with fibers provides added stiffness and strength. What’s next for fiber-reinforced polymers for use in automotive parts? Crucial research. But there’s one thing standing in the way: there is currently no industry-accepted standard specimen configuration or procedure for high-rate tensile testing of fiber-filled polymers.
Without a standard, testing is essentially self-serving. In order for research and testing to fulfill its purpose and facilitate the increased use of fiber-reinforced polymers in car parts, we must set standards for generating material properties for plastics with fiber. To do this, we need your support.
The American Chemistry Council (ACC) and the University of Dayton Research Institute (UDRI) are now spearheading an effort to develop a high-rate tensile test standard for fiber-reinforced polymers. This effort is slated to begin with a kick-off meeting involving those in industry, government, and academia who use, generate, or apply high-rate material property data. The meeting is planned for June 5, 2014 in Troy, Michigan.
ACC and UDRI have arranged the research for the industry. Now we need those who have an interest in supplying the automotive value chain to speak up, participate, and perhaps test some of their components.
UDRI will serve as the key technical contact to organize and help establish a group of committed and interested parties to support development of the standard. The University of Dayton (UD) and UDRI have a long history in materials, structures, and mechanical systems research. In fact, the Structures and Materials Evaluation Group of UDRI (SME-UDRI) was previously funded by the ACC to develop a high-rate tensile specimen that would be suitable for fiber-reinforced polymers. SME-UDRI was successful in identifying key requirements for proper measurement of the tensile mechanical properties and determined the mechanical properties of fiber-reinforced polypropylene at nominal rates up to 500/s.
However, the consortium that developed the high-rate tensile standard for unfilled polymers (SAE J24749) recognized that there were three significant concerns with the geometry in the high-rate standard:
- The effect that the geometric transition from the tab-to-gauge portion of the specimen and the molding conditions have on the distribution and orientation of fibers in long-fiber reinforced polymers (or long-fiber filled polymers);
- The stress state in the gauge area and the stress concentration at the specimen radius;
- The length of the fibers relative to the specimen gauge length, width, and thickness.
Now ACC and UDRI are leading an effort to expand the SAE J2749 standard to include fiber-filled polymers. UDRI will serve as the facilitator at the initial meetings to help identify the concerns and needs of the industry, to define the scope, and establish the phases to achieve the standard. Now more than ever, your input is needed. Please help us to define the scope of the effort and identify those who are willing to commit to the development of the standard.
Will you join me at this meeting? What you’d stand to gain is a major impact on the safety and efficiency of the cars of the future. A revolution is coming to the auto industry, by way of fiber-filled polymer composites, that will open up the landscape for automobile lightweighting without sacrificing vehicle safety. And you can be a part of it. Contact me if interested in participating.
If you’re interested in contributing your time and expertise to facilitating strong yet lightweight car parts by helping to develop high-rate tensile testing standards for fiber-reinforced polymers, contact me today for additional information and for details on how you can get involved. The future of fiber-filled polymers in car parts now depends on you.
eMail: Susan.Hill@udri.udayton.edu phone: +1.937.229.2190
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