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Simulation, Reconstruction, And Biomechanical Analysis Of Motorcycle Crashes

By Jesse Wobrock, Ph.D.

The major objective of this research was to use motorcycle and rider models in a crash simulation to identify injury mechanisms, injury trends, and injury potential to motorcyclists in one particular type of collision. MADYMO (MAthematical DYnamic MOdel), a commercially available software program, was used to construct and analyze realistic motorcycle crash scenarios in an effort to understand the dynamics of the motorcycle-rider system. Modification strategies were also investigated, which mainly involved identifying possible injury trends based on changes in motorcycle geometry. Validation of the models used was previously performed (motorcycle validation by Neiboer et al, 1993, and MATD validation via ISO 13232) using proven scientific biomechanical and collision analysis procedures.

Modifications in the simulations were limited to changes in Delta-V, handlebar location, windshield presence, and gas tank orientation. Individual simulations were run with and without the geometric modification in place. Corresponding injury criteria values were calculated. Statistical analysis was then performed to determine if the change in motorcycle geometry, at different impact severities, was significant.

A total of 36 simulation runs were performed with run times of 200 ms (30 mph Delta-V), 250 ms (20 mph Delta-V), and 300 ms (10 mph Delta-V). Four basic modifications were investigated including: 1) Three vertical gas tank angles (20, 55, and 90 degrees above horizontal). 2) Two vertical handlebar positions (neutral, or 0 inches above the original location, and a 6 inch vertical extension). 3) Presence (1) or absence (0) of a windshield. 4) Change in Delta-V (10 mph, 20 mph, 30 mph). An example simulation is seen in Figure 1.

Figure 1. Velocity = 10 mph, Gas Tank = 20 degrees, Handlebars at neutral, No windshield, run time = 300 ms, at 50 ms intervals (0, 50, 100, 150, 200, 250, 300 ms)

Delta-V correlated significantly (p < .05) to all the injury parameters measured (Gadd Severity Index-GSI, Head Injury Criterion-HIC, Femur Force Criterion-FFC, Tibia Index-TI, Contiguous 3 ms, and Pelvic Force). An interesting finding regarding gas tank orientation and pelvic force was found and is exhibited in the exponential regression analysis (Figure 2). The average pelvic force increased exponentially (R2 > .99) as the gas tank angle increased.

Figure 2. Exponential regression for average pelvic force and gas tank angle

Statistically, windshield presence (or absence) correlated significantly with GSI and HIC. Although, graphically, the windshield appeared to have an affect on TI, it was not statistically significant. Handlebar location was not statistically significant with the injury parameters measured.

Dr. Wobrock’s professional experience includes providing accident reconstruction and biomechanical engineering services and writing scientific publications regarding analysis of accidents and injuries, including but not limited to slip-and-falls, driver characteristics, industrial accidents, law enforcement, helmets, automobiles, trucks, motorcycles, bicycles, and pedestrians.

The information provided in this publication should not be viewed as legal or professional advice. The publisher assumes no liability in connection with the use of published information.