Modal and temporal analysis of head mathematical models

Area of Science:

• Biomechanics
• Computational Mechanics
• Injury Biomechanics

Background:

• The human head is a complex, deformable structure, not a rigid body.
• Previous research established mathematical models (lumped, 2D/3D finite element) for head vibration analysis.
• Modal analysis distinguished lesion mechanisms based on shock spectral characteristics.

Purpose of the Study:

• To complement modal analysis with temporal analysis of head models.
• To calculate the evolution of intracranial mechanical parameters under shock conditions.
• To evaluate the influence of shock duration on intracerebral stresses and brain-skull dynamics.

Main Methods:

• Simulated constant energy shocks of variable duration.
• Utilized lumped, sagittal plane finite element, and 3D finite element head models.
• Analyzed intracerebral stresses (compression, tensile, shear), brain-skull displacement, and skull deformation.

Main Results:

• Temporal analysis demonstrated the importance of head's modal behavior in response to variable duration impacts.
• Critical shock durations (10-15 ms for triangular shocks) excite the head's first resonance frequency.
• Considering modal behavior harmonizes calculated intracerebral stresses, even for short shocks.

Conclusions:

• Head injury risk reduction requires managing impact energy, particularly at frequencies near natural frequencies.
• Intelligent impact management, considering shape and duration, is crucial in the temporal domain.
• Future strategies aim to reduce injury risk from specific mechanisms without increasing others.