Surface material effects on fall-induced paediatric head injuries: a combined approach of testing, modelling and optimisation

Abstract

The mechanism and tolerance of paediatric head injuries are not well established mainly due to the limited cadaveric tests available. Weber's studies [Experimental studies of skull fractures in infants, Z Rechtsmed. 92 (1984), pp. 87–94; Biomechanical fragility of the infant skull, Z Rechtsmed. 94 (1985), pp. 93–101] in mid 1980s contained the most extensive paediatric cadaver test data under various fall conditions in the literature. However, the limited injury measurements and the unknown material properties of the impact surfaces in Weber's tests limited their application in paediatric fall protection. In the present study, drop tests, inverse finite element modelling and optimisation were first conducted to quantify the material characteristics of four impact surfaces (carpet, vinyl, foam and blanket) used in the Weber's tests. With the impact surface material determined, five cadaver tests from Weber's studies were reconstructed using a parametric paediatric head finite element model. Results showed that the simulated strain and stress distributions on the skulls correlated well with the fracture patterns reported in the cadaver tests. The impact surface material properties developed in this study and the methods of using the parametric paediatric head model to reconstruct the cadaver tests provided valuable information for future ground surface designs for child fall protection and development of paediatric head injury criteria.