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Researchers develop computer model for crash injury risks based on precrash occupant position

Researchers led by Ashley Weaver, assistant professor at the Virginia Tech-Wake Forest University Center for Injury Biomechanics, have developed a method to compute crash injury metrics and risks as functions of precrash occupant position.

The process allows for quantification of the sensitivity and uncertainty of the injury risk predictions based on occupant position to understand further important factors that lead to more severe motor vehicle crash injuries. The modeling results provide details not available from using crash test dummies (anthropomorphic test devices, or ATDs).

More than 33,000 Americans die in motor vehicle crashes annually, according to the Centers for Disease Control and Prevention. Modern restraint systems save lives, but some deaths and injuries remain, and restraints themselves can cause some injuries. Although crash-test dummies help engineers design safer cars, they provide only limited information about forces the body experiences during impact.

Computer models of vehicle crashes, on the other hand, can provide more sophisticated information on how to improve restraints and other safety systems. The models also help researchers simulate the effects of thousands of variables that would be far too slow to test in physical crash tests.

There’s really limited information you can get from a crash-test dummy—you get only about 20 data points. The human body model gives us much more, predicting injuries in organs that aren’t in that dummy, such as lung contusions.

—Ashley A. Weaver

The Crash Injury Research and Engineering Network (CIREN) has created a database of real-world vehicle crashes for researchers to test with computer models. Working with Joel Stitzel and graduate students and staff from the Center for Injury Biomechanics, Weaver developed a 3-phase real-world motor vehicle crash (MVC) reconstruction method to analyze injury variability as a function of precrash occupant position for 2 full-frontal CIREN cases.

The researchers used the NSF-supported Blacklight supercomputer at the Pittsburgh Supercomputing Center and the DEAC Cluster at Wake Forest University to run thousands of simulations drawn from hundreds of cases. The simulations used virtual versions of the Toyota Camry and Chevrolet Cobalt.

Lumbarinjury
Among other findings, the Blacklight simulations suggested that the lumbar spine would experience higher stress when a driver starts in a more reclined position. Credit: Wake Forest University Center for Injury Biomechanics Click to enlarge.

Weaver worked with members of the Extreme Science and Engineering Discovery Environment (XSEDE) Extended Collaborative Support Service team—staff with expertise in many areas of advanced computing—who helped set up the cyberinfrastructure and workflows needed to run the simulations.

Supported by a five-year, $121-million NSF grant, XSEDE provides a collection of integrated digital resources that scientists can use to access advanced computing resources, data and expertise.

Using the Total Human Model for Safety (THUMS), developed by Toyota Central Research and Development Labs, Weaver and her team showed that simulations can reproduce real-world injury patterns and predict details crash-test dummies can’t provide.

Along the way, they demonstrated how injury-causing stress moves from the foot to the lower leg as a driver’s head comes forward into a frontal airbag, and that more reclined seating positions can lead to a higher risk of head and chest injuries.

Weaver and her colleagues published their findings in an open-access paper in Traffic Injury Prevention.

The reconstruction process allows for quantification of the sensitivity and uncertainty of the injury risk predictions based on occupant position, which is often uncertain in real-world MVCs. This study provides perspective on the injury risk sensitivity of precrash occupant positioning within the vehicle compartment. By studying a variety of potential occupant positions, we can understand important factors that lead to more severe injuries and potentially mitigate these injuries with advanced safety systems to protect occupants in more dangerous positions. Evaluating additional cases in further detail will allow for development of new injury metrics and risk functions from real-world crash data to assess the effectiveness of restraint systems to prevent and mitigate injuries that are not easily studied using postmortem human subjects or ATDs.

—Gaewsky et al.

Resources

  • James P. Gaewsky , Ashley A. Weaver , Bharath Koya , Joel D. Stitzel (2015) “Driver Injury Risk Variability in Finite Element Reconstructions of Crash Injury Research and Engineering Network (CIREN) Frontal Motor Vehicle Crashes” Traffic Injury Prevention Vol. 16, Iss. sup2 doi: 10.1080/15389588.2015.1061666

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