*3.1.2. FE Model properties*

After exporting all four models in to ABAQUS, further simulation was done on randomly selected one of the four models. Tables 2-3 provide the subject specific dimensions and mechanical properties of the cadaver heads (computational models) used in this study. All four meshed-head models after exporting into the ABAQUS are shown in Figure 13. Further smoothening to reduce distorted elements was performed.

Skull: Total no of nodes: 51988 and total no. of elements: 210938

Brain: Total no of nodes: 36585 and total no. of elements: 145151

Young modulus, poisson's ratio and density are described in section 2.2


**Table 2.** Young modulus, density and poison's ratio of the head [3]


**Table 3.** Volumes, surfaces and number of elements (triangles) of four skulls

Elastic properties were assigned to brain. As per the [3, 35] viscoelastic or elastic properties do not make any fundamental change to the FEM response. Boundary condition details were provided in Figure 14.

**Figure 12.** Use of Mimics to create 3D models of human head

**Figure 13.** Four meshed skulls in ABAQUS

106 Injury and Skeletal Biomechanics

exported into the ABAQUS [45].

smoothening to reduce distorted elements was performed.

**Table 2.** Young modulus, density and poison's ratio of the head [3]

**Table 3.** Volumes, surfaces and number of elements (triangles) of four skulls

were provided in Figure 14.

Elastic properties were assigned to brain. As per the [3, 35] viscoelastic or elastic properties do not make any fundamental change to the FEM response. Boundary condition details

Skull: Total no of nodes: 51988 and total no. of elements: 210938 Brain: Total no of nodes: 36585 and total no. of elements: 145151

Young modulus, poisson's ratio and density are described in section 2.2

 Outer table 7300 0.22 3000 Dipole 3400 0.22 1744 Inner table 7300 0.22 3000 CSF 2.19 0.489 1040 Brain 2190 0.4996 1040

*3.1.2. FE Model properties* 

Skull

segmentation tools allow user to segment the medical CT/MRI images, and take measurements. The designs can be modified based on the simulation outcomes and can be exported to the FEA/CFD packages [44]. Additional steps like assigning material properties, part sections, assemblies, load, boundary conditions and analysis for head models then

After exporting all four models in to ABAQUS, further simulation was done on randomly selected one of the four models. Tables 2-3 provide the subject specific dimensions and mechanical properties of the cadaver heads (computational models) used in this study. All four meshed-head models after exporting into the ABAQUS are shown in Figure 13. Further

Material Young modulus E(Mpa) Poisson's ratio (ν) Density ρ (kg/m3)

**Figure 14.** Blue/purple markers show the spots on at neck-head junction where boundary conditions were applied

As shown in the fig., boundary conditions were defined at the four points around the headneck junction to restrict all transactional movement. Short duration impacts (<6ms), the neck does not influence the kinematic head response [35].
