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Étude du comportement dynamique de matériaux composites sous sollicitations de chocs : application à un casque aéronautique

Abstract : The structural components of the helmet are designed to protect the head from impact by dissipating the kinetic energy of the projectile and ensuring that any contact between the projectile and the impacted body is avoided. Most of the energy is dissipated by the inner core but the outer shell must be designed with the greatest attention since the structure has several critical roles during impact: resisting the perforation by the projectile and assisting the distribution of load on the foam. In addition, from a design point of view, the mass gain may be more important on the shell than on the foam. Though the outer shell and the inner foam are both essential, particular attention is paid to the helmet shell. The objective of this research, in collaboration with Thales Avionics, is to establish a relationship between phenomena occurring at the microscopic level and the macroscopic response. The study will provide significant new information to industry to aid them in selecting materials with improved characteristics under impact. A first series of tests revealed that the addition of triblock copolymer (Nanostrength) in the matrix of the Kevlar/Epoxy composite significantly increased the impact performance of the composite. The influence of the physico-chemical parameters on impact behavior was studied. It was observed that a high fibre weight fraction coupled with 10% Nanostrength considerably improved puncture resistance and increased the energy dissipated. Next, in order to understand the processes that promote energy dissipation and model numerically the helmet shell a behavior law was chosen. The model was an elastic material model with damage. Quasi-static and dynamic tests were performed to obtain the material parameters. The model identification was optimized and validated by comparing experimental data and simulation results. This work presents a significant first step towards developing a numerical model of the helmet that can quantify the phenomena and optimize the structure for industrial applications.
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https://pastel.archives-ouvertes.fr/pastel-00683487
Contributor : Sébastien Denneulin <>
Submitted on : Wednesday, March 28, 2012 - 9:47:42 PM
Last modification on : Friday, October 23, 2020 - 4:37:59 PM
Long-term archiving on: : Friday, June 29, 2012 - 2:30:31 AM

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  • HAL Id : pastel-00683487, version 1

Citation

Sébastien Denneulin. Étude du comportement dynamique de matériaux composites sous sollicitations de chocs : application à un casque aéronautique. Matériaux et structures en mécanique [physics.class-ph]. Ecole nationale supérieure d'arts et métiers - ENSAM, 2011. Français. ⟨NNT : 2010ENAM0038⟩. ⟨pastel-00683487⟩

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