Determination of Mechanical Properties of Human Skull With Modal Analysis

Abstract

Traumatic brain injury (TBI) may happen due to loads at high rates. Due to the limitations in experimental approaches, computational methods can simulate and quantify mechanical properties. The experiments show that the human skull has nonlinear mechanical behavior and is significantly strain rate dependent. In this study, we implement Mooney-Rivlin nonlinear hyper and linear-elastic constitutive models to the experimental tensile data at different strain rates; 0.005, 0.1, 10, and 150 1/sec. A dried human skull including frontal, parietal, and occipital bones, was modeled by the 3D laser scanner and discretized by HyperMesh software to perform modal analysis using LS-Dyna finite element software. Using a roving hammer experimental modal analysis scheme, the frequency response function (FRF) and the first three natural frequencies of the skull will be measured. We found these natural frequencies are 496.9 Hz, 560.9 HZ, and 1246 Hz. Performing numerical modal analysis on the skull with pre-assumed linear elastic properties at high strain rate showed close natural frequencies as obtained by experiments. This study provides a new insight into a better understanding of the nonlinearity dynamical behavior of the human skull.

Characterizing Natural Frequencies of the Hybrid III and NOCSAE Headforms

“…To evaluate which headform's vibrational response is more representative of the human head, we compared our results to studies done on the vibrational characteristics of humans. Both experimental and analytic tests have been performed, and although analytical results carry value, we chose to primarily focus on the results of experimental studies or analytical studies that validated their models with experimental techniques [12,17,20,22]. Finite element modeling [23,[26][27][28] or mathematical modeling [24,29,30] tended to have a wider range of natural frequency values.…”

“…In head impacts, even relatively low-magnitude impacts can cause damage if the frequency generated by the impact corresponds to one of the head's natural frequencies [10]. While no studies have looked at the vibrational response of ATD headforms, there have been previous attempts to characterize these dynamic properties of the human head through various experimental [7,[11][12][13][14][15][16][17][18][19][20][21][22] or computational modal analysis techniques [23][24][25][26][27][28][29][30]. The techniques used in these experimental tests were either forms of mechanical impedance tests or hammer impact tests, where the subjects were human cadaver skulls [7, 12-14, 16, 18, 20], human heads in vivo [7,13,15,22], and various polymer skull models [14,17,21].…”

Multiscale Computational and Artificial Intelligence Models of Linear and Nonlinear Composites: A Review

“…Computational research groups, along with their experimental research collaborators, [66][67][68] have invested considerable research efforts in computation modeling of BWM (FEM [69][70][71] and ML [68] based). Over the years, many findings regarding [72] the mechanical response of BWM for a variety of impacts (uniaxial to the multiaxial case), TBIs, aging, [73] and fatigue load scenarios on the brain tissues [74,75] have been put forward. Similarly, researchers from Karami et al have intensively studied TBI and brain soft tissue composite modeling.…”

The Strain Rates in the Brain, Brainstem, Dura, and Skull under Dynamic Loadings

“…Both theoretical and experimental studies have shown that the dura and cranial bone present rate-dependent material properties [30][31][32][33][34]. Although linear and hyperelastic models can approximate the behavior of dura and skull very well at each rate [31,35,36], they behave differently under various speeds of loading. For instance, Persson et al [31] tested dura mater under uniaxial tension at three various strain rates of 0.01, 0.1, and 1.0 s −1 .…”