Influence of surrogate scalp material and thickness on head impact responses: Toward a biofidelic head-brain physical model

• Published in: Journal of the mechanical behavior of biomedical materials Vol. 142; p. 105859
• Main Authors: Li, Yizhao, Vakiel, Paris, Adanty, Kevin, Ouellet, Simon, Vette, Albert H., Raboud, Donald, Dennison, Christopher R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.06.2023
• Subjects: Acceleration; Biofidelity; Biomechanical Phenomena; Blunt impact; Brain; Craniocerebral Trauma; Head; Head kinematics; Head surrogate; Headform; Humans; Intracranial pressure; Scalp; Biofidelity; Head kinematics; Head surrogate; Intracranial pressure; Blunt impact; Headform
• ISSN: 1751-6161; 1878-0180
• DOI: 10.1016/j.jmbbm.2023.105859

Advanced physical head models capable of replicating both global kinematics and intracranial mechanics of the human head are required for head injury research and safety gear assessment. These head surrogates require a complex design to accommodate realistic anatomical details. The scalp is a crucial head component, but its influence on the biomechanical response of such head surrogates remains unclear. This study aimed to evaluate the influence of surrogate scalp material and thickness on head accelerations and intraparenchymal pressures using an advanced physical head-brain model. Scalp pads made from four materials (Vytaflex20, Vytaflex40, Vytaflex50, PMC746) and each material with four thicknesses (2, 4, 6, and 8 mm) were evaluated. The head model attached to the scalp pad was dropped onto a rigid plate from two heights (5 and 19.5 cm) and at three head locations (front, right side, and back). While the selected materials’ modulus exhibited a relatively minor effect on head accelerations and coup pressures, the effect of scalp thickness was shown to be major. Moreover, by decreasing the thickness of the head’s original scalp by 2 mm and changing the original scalp material from Vytaflex 20 to Vytaflex 40 or Vytaflex 50, the head acceleration biofidelity ratings could improve by 30% and approached the considered rating (0.7) of good biofidelity. This study provides a potential direction for improving the biofidelity of a novel head model that might be a useful tool in head injury research and safety gear tests. This study also has implications for selecting appropriate surrogate scalps in the future design of physical and numerical head models. •We evaluated surrogate scalp influence on impact responses of a head-brain model.•Scalp thickness has a dominant effect for both low and high height drops.•Scalp material has slight effects for low drops and no effects for high drops.•Decreasing the original scalp thickness greatly improves the kinematic biofidelity.