How Can We Help?
Abdomen Bar
Background
The Abdomen Bar tool is used to process simulation results from a Hardy-type bar impact [1]. This tool becomes active when rigid body part ID 600000 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 impact consists of a 2.5 cm diameter, 48 kg bar with a prescribed impact velocity of 6.0 m/s. This is a free-back impact and occurs at the level of the umbilicus, or approximately L3. To represent the effective limit to abdominal compression, deflection corridors from literature are normalized by the compressible abdominal depth of the PMHS for comparison to the model [2]. Compressible abdominal depth is defined as the abdominal depth from the anterior surface of L3 to the anterior surface of the body normal to L3, i.e. the L3 depth. The force of the impact is measured as the contact force of the rigid bar.
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 Hardy et al. 2001 corridors. Note the deflection axis has been normalized according to “compressible abdominal depth” (see processing methods). 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 | |
| Added mass and %Added mass as a function of initial mass are reported for the human body model | Human Body Model Energy Plot |
Data Processing Methods
Compression
1. Extract coordinates of the CG of the bar using RBDOUT for PID 600000
2. Extract nodal coordinates L3
a. For GHBMC M50-O v5.1.1: Default Node ID 6104521
b. This default node ID can be overridden in Human Body Model Settings under Nodes->L3
3. Deflection is calculated using the change in the Euclidean norm between bar and L3
4. Deflection (step 3) is normalized by initial anterior abdominal depth. Anterior depth is compressible space anterior to spine, according to the formula:
Anterior Abdominal Depth = Total Abdominal Thickness – Thickness Posterior to Spine
a. For GHBMC M50-O v5.1.1: Anterior abdominal depth = 128mm (Total Abdominal Thickness = 227 mm, Thickness Posterior to Spine = 99 mm)
b. This default measurement can be overridden in Human Body Model Settings under Measurements->Anterior Abdominal Depth
Force
1. Extract resultant contact force data for
a. For Hub in GHBMC M50-O v5.1.1 Simulation: RCFORC ID 600000
2. Filter using SAE CFC 600
References
[1] Hardy, W.N., Schneider, L.W., and Rouhana, S.W. (2001) Abdominal impact response to rigid-bar, seatbelt, and airbag loading. Stapp Car Crash J 45: 1-32.
[2] Vavalle, N.A., Moreno, D.P., Rhyne, A.C., Stitzel, J.D., and Gayzik, F.S. (2013) Lateral impact validation of a geometrically accurate full body finite element model for blunt injury prediction. Ann Biomed Eng 41 (3): 497-512.