Predicting the Kinematic Response of a Helmeted Headform during Oblique Impacts

Abstract

160 oblique impact tests were performed to study the relationship between the kinematic response of a helmeted headform and impact severity caused by the change of speed (Group 1) and anvil angle (Group 2). For this work, the kinematic response of a helmeted headform is evaluated by measuring linear acceleration, rotational acceleration, and rotational velocity of the headform. In Group 1, a football helmet was tested at 45o anvil angle at four different impact speeds ranging from 4.5m/s and 7.4m/s on five impact locations. Results showed that for all cases, the relationship between impact speed and helmeted headform kinematic response was linear, with an average R2 value of 0.98. In Group 2, the helmeted headform was tested at 5.5m/s impact speed at six different anvil angles between 15o and 55o, and the response was fitted with a second-degree polynomial (curve) with an average R2 value of 0.96. The predicted helmeted headform kinematic response was obtained and validated experimentally, and the average error was found to be 8.3%. The results showed that it is possible to predict the kinematic response of a helmeted headform by interpolating or extrapolating the data without having to perform extra impact test.