Equipment

The Composites Laboratory operates a unique servo-hydraulic test machine, the Integrated Physical and Virtual Test Machine for Automotive Crashworthiness (TMAC), to conduct progressive crushing tests on composite automotive components at velocities ranging from 0-29 km/hr and energy levels up to 50 kJ. Using this machine, researchers can study the deformation and failure response of composite components in relation to impact velocity in a controlled and programmable manner made possible by a unique adaptive control feature of the software. TMAC is principally used to test composite structures, but it is also a superb tool for conducting progressive crush tests on other structural materials.

The machine was installed at NTRC in October 2002.

Photo shows aluminum honeycomb specimen before and after crush. The specimen exhibited a sustained crush force of 133 kN (30,000 lbs) at a velocity of 6 m/s. Total crush distance was 230 mm (9 in) and was halted only by the limited travel of the ram.

TMAC Uses

Advanced lightweight materials, such as polymer composites, aluminum, and high-strength steels, offer better crash energy absorption per unit of mass than do traditional materials.

When those materials are tested to assess their response to crushing they exhibit different behaviors at different impact velocities. What happens in the transition zone between quasi-static impact rates (e.g., 2 inches per minute) and high-velocity impacts (over 10 mph) is not understood because the capability to conduct impact tests at intermediate velocities has been lacking. TMAC now fills that gap.

The capability to test across this range of velocities and energy levels is providing the critical data needed for crash simulations that assess the safety of vehicles body structures manufactured from composites and other lightweight materials.

For More Information

For more information on composites research at Oak Ridge National Laboratory, see http://www.ms.ornl.gov/researchgroups/composites/mainframe.htm

Contact:

J. Michael Starbuck
Phone: 865-576-3633
Email: starbuckjm@ornl.gov

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