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Thorax Hub
Background
The Thorax Hub tool is used to process simulation results from a Kroell-type chest impact. This tool becomes active when node ID 5100091 on a rigid impactor is in the loaded binout data. The goal of the tool is to allow users to compare model outputs to both literature data and to the baseline GHBMC model following internal modifications.
The chest impact uses a 23.4 kg cylindrical hub impactor with a 15 cm diameter and a prescribed impact velocity of 6.7 m/s [1]. According to the experimental description, the impactor is aligned in the mid-sagittal plane at the level of the 4th intercostal space. Thoracic deflection is described as the change in chest depth throughout the simulation. Forces are reported as the contact force of the impactor. The model outputs are compared to the corridors developed by Lebarbé and Petit through a meta-analysis of several chest impact studies [2]. The sample was comprised of 19 high speed impacts with 14 males and 5 females.
The boundary condition files for validation cases are available in a directory called “validation_cases” within the Metriks installation folder: e.g. C:/Program Files (x86)/Metriks/validation_cases
| Panel Descriptions | |
|---|---|
| Graphic of impact boundary condition and relevant simulation and post-processing information | Force vs Deflection response plotted against the Lebarbe et al. 2012 average male corridors. The user loaded model is plotted in red and the baseline M50-O v5.1 with fracture on is plotted in black. |
| Key aspects of the energy balance for the full simulation are reported | Human Body Model Energy Plot |
| Added mass and %Added mass as a function of initial mass are reported for the human body model | |
Data Processing Methods
Compression
1. Extract nodal coordinates for sensor node on the impactor and T8
a. For GHBMC M50-O v5.1.1: Default impactor NID 5100091 and T8 NID 4198200
b. These default node IDs can be overridden in Human Body Model Settings under Nodes->Kroell Chest and Nodes->Kroell T8 Flesh
2. Calculate deflection using the change in the Euclidean norm between impactor and T8 nodes
Force
1. Extract resultant force data for hub to flesh contact
a. For GHBMC M50-O v5.1.1: RCFORC ID 4500000
2. Filter using SAE CFC 300
References
[1] Kroell, C.K., Schneider, D.C., and Nahum, A.M. (1974) Impact tolerance and response of the human thorax II. SAE Technical Paper 741187.
[2] Lebarbé, M., and Petit, P. (2012) New biofidelity targets for the thorax of a 50th percentile adult male in frontal impact. Proc. 2012 International IRCOBI Conference on the Biomechanics of Impact. Dublin, Ireland, pp. 856-870.