The effect of impactor location and velocity variation on validation of an advanced human body finite element model

Finite Element Modeling (FEM) is increasingly used as a tool in the field of injury biomechanics. One challenge in validating human body FEMs is quantifying the effect that variability of input parameters from experiments can have on the model’s predictions. The objective of this study was to conduct a parametric study on a validation simulation of the Global Human Body Models Consortium’s 50th percentile male model. The selected case was an oblique hub impact to the thoracoabdominal region of the model’s right side. The hub impactor was a 23.4 kg cylinder, with a 15cm diameter, given an initial velocity. The location and velocity of the impactor were varied based on the reported variance of the experiments used as the basis of these simulations. The effect that these changes have on the peak force was observed. Fifteen cases were simulated, giving results for five locations and three velocities based on a nominal velocity (6.7 m/s) and placement. The nominal impactor location was 7.5 cm below the xiphoid process and 30° from lateral, as described in the literature. The nominal velocity was varied ± 2 standard deviations from the average experimental velocity. The study results indicate that there were both location-based and velocity-based dependencies. There was a 5.5% increase in peak force when increasing the velocity by 0.3 m/s and a 6.4% decrease in peak force when decreasing the velocity by 0.3 m/s. Additionally, the Force vs. Time curves of the same impactor location showed a trend of similar curve shapes. The impactor location also had an impact on the number of rib fractures predicted by the model as well as the time of the peak force. The parameters used in this study represent typical experimental variation in location and velocity and show the model is reasonably robust within range of plausible impacts.