In most cases, NCAC researchers must consider and analyze several design options and crash scenarios for each effort they undertake. And because of the related expense, researchers save live crash testing for end-stage designs and scenarios. Instead, before the crash-test stage, they take full advantage of the more cost-effective and flexible FE computer modeling tools, simulating the range of options.
In NCAC's Vehicle Modeling Laboratory, researchers “reverse engineer” vehicles to develop models that virtually recreate automobiles and trucks. With these accurate models, the researchers can simulate several different crash scenarios and predict vehicle and occupant response to incidents. Such foresight leads to more efficient research time and more effective and useful data for making safety decisions.
Developing accurate and comprehensive FE models is a complex task that requires precise detail work and a tremendous amount of mathematical computation. Researchers must:
- Apply tape over an entire vehicle to get an accurate representation of the geometries
- Digitize every component using a seven-degree-of-freedom coordinate measuring machine
- Disassemble all vehicle components
- Collect mass and material thickness data for vehicle and individual parts
- Identify all parts and connections
- Conduct center-of-gravity calculations
- Execute material property tests for component strength
- Create a computerized “mesh” grid of the vehicle using advanced computer codes
- Reconnect all parts accurately, including spot welds, rigid body constraints, joints, springs and dampers.
The methodologies developed in the Vehicle Modeling Laboratory have also been used to determine physical data of such other devices as anthropomorphic test dummies, child car seats, highway barriers and crashed components. These methodologies have been published extensively and are now being used by research organizations worldwide.
NCAC's Vehicle Modeling Laboratory relies on high-end computer-aided design (CAD) workstations and the computational capabilities of the Center's High-Performance Computing Laboratory to create the models, which become the tools for conducting crash simulations and analyzing live crash tests. Researchers will continue to evaluate such new reverse-engineering technologies as optical laser scanning and robotics-based scanning to improve the efficiency and quality of future vehicle, component and system models.