Head Blunt Impact (Raymond 2009)¶
Model validation information
- Performed by : Yash Niranjan Poojary, Stina Granholm
Added to VIVA+ Validation Catalog on :
Last modified : 29th September 2025
ViVa Model version: 2.0.1 released on 2025-04-11
LS Dyna version: smp d R16
Experiment by Raymond et al. (2009)¶
Summary:¶
In Raymond et al. [1] PMHS were struck by a circular impactor at two different impact conditions. In the following the experiment data is compaired to simulated data for different conditions.
{image}
:alt: Blunt impact
:align: center
Information on the subjects/specimens¶
| No. | Specimen ID | Age | Sex | Head mass [kg] |
|---|---|---|---|---|
| 1 | 2426 | 69 | M | 3.26 |
| 2 | 2427 | 57 | M | 2.98 |
| 3 | 2904 | 74 | M | 4.30 |
| 4 | 2939 | 63 | F | 3.28 |
| 5 | 2965 | 75 | F | 3.42 |
| 6 | 2908 | 73 | F | 3.48 |
| 7 | 2978 | 55 | F | 3.10 |
Loading and Boundary Conditions¶
- Low-Speed (LS) and High-Speed (HS) impacts bilaterally in a paired randomized manner.
- Impactor made from Aluminum 6061 with diameter 38 mm and weighing 103 grams is propelled into the test specimen using compressed air.
- The specimen was suspended to allow for impacts at 25 mm anterior to the external acoustic meatus and 35 mm superior to the Frankfurt plane.
Impact conditions¶
Two different impact conditions were used a which was roughly 20 m/s and b which was roughly 33 m/s.
| No. | Specimen ID | Velocity-Left side Impact [m/s] | Velocity-Right side Impact [m/s] |
|---|---|---|---|
| 1 | 2426 | 32.1 | 22.22 |
| 2 | 2427 | 34.2 | 23.4 |
| 3 | 2904 | 31.9 | 17.3 |
| 4 | 2939 | 16.3 | 34.4 |
| 5 | 2965 | 18 | 35.2 |
| 6 | 2908 | 35.1 | 19.6 |
| 7 | 2978 | 19.5 | 32.4 |
Responses recorded¶
- Impactor velocity was measured by an light-emitting diode-based velocity trap mounted at the end of the cannon barrel.
- Impact force was calculated by multiplying the acceleration signal of the impactor by the total impactor mass.
- Deformation was determined through double integration of the impactor accelerometer and verified by digital image tracking from the high speed video.
The reference values from the paper were digitalised and are incuded in the notebook. The data corresponds to the unnormalised corridors.
- Raymond, David, et al. "Development of biomechanical response corridors of the head to blunt ballistic temporo-parietal impact." Journal of biomechanical engineering 131.9 (2009) DOI: 10.1115/1.3194751
Simulations¶
Velocity for average models¶
The velocities used for the average models were chosen by taking the average velocity for each impact condition.
| Impact Condition | Average speed [m/s] | Average speed excl. 2427 [m/s] |
|---|---|---|
| A | 19.5 | 18.8 |
| B | 33.6 | 33.5 |
The sample 2427 was excluded due to demonstrated higher stiffness as described in Raymond et al, the data from 2427 was not used in producing the corridor as also stated in Raymond et al.
Scaling¶
The head models were scaled with respect to head mass to match each PMHS, the mass of the head model for males were ~4.5 kg and for females ~3.8 kg. The scaling factor was calulated by the following equation: $$ \text{Scaling factor} = \sqrt[3]{\frac{\text{PMHS Mass}}{\text{Head Model Mass}}} $$ The scaling was then applied in all directions of the head (x, y, z).
When scaling the head model the impact between the impactor and the head gets delayed. The displacement in the simulation is measured by the displacement of the impactor. In order to make sure only the distance of the head impact is used the displacement is assumed to start when the force goes over a value of 0.13. The value was selected by testing different values and seeing when noise was excluded as false starts.
Read dynasaur csv files¶
Simulated averages¶
Simulated scaled induviduals¶
The binout is extracted using dynasaur, to extract force-displacement data and exclude some of the noise a filter is used. However, further investigation into the filter should be done to validate the output, it seems too much data is being filtered no matter the changes done to the filter.
