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Mécanismes de rupture des côtes et critères de tolérance thoracique en choc automobile

Abstract : The highlight of a divergence between road accidents and crash-tests requires a revisit of thoracic injury criteria. Meanwhile, the rise of new numerical dummies allows the creation of localised injuries; which could not exist with physical dummies such as Hybrid III. In these localised injuries, there is the rib fracture. In this context, this work has been articulate around the development and validation of a breakable personalised numerical model of ribs in impacts. Related to bibliography, three points bending tests were chosen, including measures of deformation with strain gages and cinematic observations using video. Testing conditions were validated in regard to different models and information: HSPM tests, mass-spring system, strength material theory and finite elements analysis. Prior to testing, each rib has been scanned to study its geometry and generate its personalised mesh in finite elements. Static tests, using ribs 6, 8 and 10, right and left, show an increasing ultimate force from rib 6 to 10 and a displacement at the ultimate force highly higher for rib 10. Dynamic tests, with a different speed for each rib level and a different impactor shape (cylindrical and seat-belt like impactors) for each side, show a strong influence of speed and impactor geometry. We can point out an optimal speed, in term of ultimate force, between 0,10 and 0,25 m.s-1 and also, by changing a cylindrical impactor by a seat belt impactor, as the rib get ruined for the same displacement, it can bear a strength higher of 30%. This is similar to the conclusions observed in accidentology. The geometrical study shows that rib characteristics change with level, but note the linear concentration of minerals. At last, first finite elements analysis, aiming to reproduce those tests, did validate the feasibility of the modelisation, and opened development perspectives.
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Contributor : Stéphane Diet <>
Submitted on : Wednesday, February 23, 2011 - 9:03:04 PM
Last modification on : Friday, October 23, 2020 - 4:40:29 PM
Long-term archiving on: : Saturday, December 3, 2016 - 8:39:20 PM

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  • HAL Id : pastel-00568920, version 1

Citation

Stéphane Diet. Mécanismes de rupture des côtes et critères de tolérance thoracique en choc automobile. Biomécanique [physics.med-ph]. Ecole nationale supérieure d'arts et métiers - ENSAM, 2005. Français. ⟨NNT : 2005ENAM0001⟩. ⟨pastel-00568920⟩

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