Etude du comportement sous choc d'un matériau énergétique par spectroscopie Raman in situ

Abstract : Improving performances and safety of pyrotechnic devices requires a sharp knowledge of the shock to detonation transition phenomenon in high explosives. Current models to describe this phenomenon largely involve empiric parameters based on macro scale experiments. To improve predictive capability of these models, it is necessary to get experimental data at a microscopic scale. To provide such data, we developed an experimental setup to shock a high explosive up to 30 GPa and perform in-situ measurement of its Raman spectra under this loading. The device includes a shock generator based on explosive driven plate impact triggered by a laser pulse and a diagnostic involving an excitation laser and a spectrometer coupled with an intensified CCD. This experiment has been applied to an insensitive high explosive named TATB. Pressure driven evolution of the Raman spectra reveals an important coupling between NO2 and NH2 vibration modes that is due to a strong H bonding within TATB crystal. This bonding is clearly linked to TATB high stability. Differences observed between dynamic and static loading are attributed to shock heating resulting in H bonding weakening. Moreover, results show a progressive decrease in Raman spectra intensity with increasing shock pressure down to a complete signal loss at about 9 GPa. High speed visualisations reveal a progressive darkening of the sample leading to complete opacity at 9 GPa. Reflectivity measurements under shock loading show that these two phenomena are due to a shock-induced enlargement of the TATB absorption band.
Document type :
Theses
Complete list of metadatas

Cited literature [181 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01127545
Contributor : Abes Star <>
Submitted on : Saturday, March 7, 2015 - 3:23:40 AM
Last modification on : Tuesday, June 4, 2019 - 6:21:39 PM
Long-term archiving on : Monday, June 8, 2015 - 3:51:04 PM

File

2014ESMA0025.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01127545, version 1

Collections

Citation

Charles Saint Amans. Etude du comportement sous choc d'un matériau énergétique par spectroscopie Raman in situ. Autre. ISAE-ENSMA Ecole Nationale Supérieure de Mécanique et d'Aérotechique - Poitiers, 2014. Français. ⟨NNT : 2014ESMA0025⟩. ⟨tel-01127545⟩

Share

Metrics

Record views

396

Files downloads

835