Investigation of the Effect of Child Helmet Design Parameters on Head and Brain Injuries Using Reduced-Order Modelling

A helmet is the main protective equipment for a child pillion passenger. A safe helmet must be able to mitigate head and brain injuries resulting from high head impact loading. A lightweight helmet is preferable, especially for children. This paper proposed to study the effect of materials, liner thickness, and friction at the head–helmet interface on linear and rotational accelerations using reduced-order modelling. A child head–helmet finite element model was developed and validated against an experiment. Finite element simulations were conducted to generate training data for the establishment of reduced-order models which were subsequently used to predict the linear and rotational accelerations for various helmet parameters. The prediction could be performed in a very short time compared to its corresponding finite element simulation. The use of aluminium foam enhanced mitigation of the linear and rotational accelerations as well as weight reduction. This study also revealed that the head–helmet friction coefficient had a strong effect on the rotational acceleration, while the liner thickness predominantly affected the linear acceleration. However, the liner thickness had less influence on the rotational acceleration when the head–helmet friction was low. The risk of brain concussion as well as diffusional injury could be reduced by enabling low friction at head–helmet surface.