High But Constant Strain Rate Materials Testing with the Testing Machine for Automotive Crashworthiness (TMAC)

National Laboratory: 
Oak Ridge National Laboratory
Characterization Class: 
Mechanical Behavior of Materials
Description: 

As part of a comprehensive approach in developing and applying composite materials, ORNL develops and maintains extensive capabilities for testing composite constituents, components, and structures utilizing standard and unique testing equipment.  One unique example is a unique servo-hydraulic test machine, the Testing Machine for Automotive Crashworthiness (TMAC). This machine is designed to conduct progressive crushing tests on composite automotive components at velocities ranging from 0-29 km/hour and energy levels up to 50 kJ. TMAC, is closed-loop servo-hydraulic machine, designed, engineered and manufactured by MTS, that permits controlled, progressive crush experiments at programmable velocity profiles and high force levels. The capability to maintain constant speed is important to keep the crush rate constant and to rate effects.

Capability Bounds: 

ORNL's Carbon and Composites Group provides wide-ranging capabilities for the design, analysis, development, evaluation, and demonstration of affordable advanced composite materials and structures. This Group functions as a key resource for research, development, prototyping, and industrial deployment of advanced composite materials applications and manufacturing technology. Working with industry, government, and academia, the Group serves as a focal point for the development and demonstration of solutions to critical issues surrounding the manufacture of cost-effective composite materials, structures and assemblies. The TMAC capability bounds include:

Capability Bounds: Physical Specifications

  • 490 KN Actuator Capacity (static conditions)
  • 250 mm Stroke
  • Greater than 490 KN side-load capacity
  • Attachable 450 kg mass to smooth impact oscillations

Example Operating Conditions

  • No Load: 115 mm travel at 8 m/s
  • Sustained force of 133 KN: 115 mm travel at 6 m/s
  • Sustained force of 267 KN: 115 mm travel at 4 m/s
Unique Aspects: 

ORNL Composites Testing capabilities include equipment established and maintained by the Carbon and Composites Group as well as leveraging world-class materials evaluation capabilities available throughout ORNL.  Among the most unique capabilities are the Tech Machine for Automotive Crashworthiness jointly developed by group members, the Automotive Composites Consortium, and MTS Systems Corporation.  It is designed to run constant velocity tests up to 8 m/s at loading of 100's of kN. This intermediate strain rate test system as shown below is augmented by a smaller modified test machine that can run up to 18 m/s.  Both machines service broad ranges of materials classifications beyond composites.  Group members have developed and deployed unique capabilities to measure chopped fiber orientation and length distributions as well as to measure tack in pre-impregnated tape and fabric.  Mechanical test capabilities include standard and unique static, fatigue, and creep/stress rupture facilities while thermo-physical capabilities include DMA, DSC, TGA, TMA, BET, DCA, FTIR, etc.  ORNL maintains extensive fiber test capabilities ranging from single-filament testing to testing of large tows; resistivity and dielectric measurements are routine incorporated into fiber R&D.  World-class microscopy and chemical analysis capabilities are available on-site as well.  Using the TMAC, we 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 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.

Availability: 

These facilities are available for various partnership arrangements with industry. 

Single Point of Contact: 

Name: Bob Norris, Senior Research Staff Member
Email: norrisrejr@ornl.gov
Phone: (865) 576-1178

Supporting Document(s):