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Preheating induced sensitization has been commonly studied in the frame of SDT but a complete analysis in terms of pyrotechnic safety needs to take into account other kinds of stimuli like “moderate” mechanical ones (crushing, drops…), new thermal fluxes or combined insults. We present the results of connected studies and propose sensitization mechanisms based on these data and on previous chemical and microstructure characterizations.

This paper is devoted to a review of microstructure observations performed on a TATB composition submitted to thermal and combined thermal/mechanical stimuli. Effects are identified and quantified in terms of decomposition extension and microstructure evolution (porosity, shear bands, grains shape and orientation, anisotropy …). Several complex mechanisms and important transformations are exhibited as a function of temperature, heating duration and shock wave intensity. Conclusions on decomposition mechanisms are directly derived from these observations.

We analyze the evolution of the sensitivity of a TATB composition after thermal cycles at elevated temperatures. Sensitization due to thermal cycles is of variable magnitude depending on the kind of the second stimulus (mechanical or thermal). In order to investigate the possible mechanisms which govern these phenomena, we perform an extensive study of the evolution of the chemistry and microstructure of our composition and we determine the sensitivity of our explosive to various stimuli after various temperature/duration cycles. This first paper is devoted to the study of TATB chemical evolutions. We present the results obtained for explosive decomposition, furazan generation, gas analyses and solid residue characterization.

International audience; This work is part of a project for evaluating catastrophic tank failures caused by impacts with a high-speed solid body. Previous studies on shock overpressure and drag events have provided analytical predictions, but they are not sufficient to explain ejection of liquid from the tank. This study focuses on the hydrodynamic behavior of the liquid after collision to explain subsequent ejection of liquid. The study is characterized by use of high-velocity projectiles and analysis of projectile dynamics in terms of energy loss to tank contents. New tests were performed at two projectile velocities (963 and 1255 m s−1) and over a range of viscosities (from 1 to 23.66 mPa s) of the target liquid. Based on data obtained from a high-speed video recorder, a phenomenological description is proposed for the evolution of intense pressure waves and cavitation in the target liquids.

International audience; We have studied the sequence of events that occurs when a high-speed projectile (from 960 m s−1 to 1480 m s−1) penetrates a vessel filled with toxic liquid. We find that prior to liquid ejection several well-defined phases occur, including the phenomenon known as the “hydraulic ram.” Then a catastrophic tank failure leads to liquid ejection and fragmentation. This paper focuses on this phenomenon and explains how it can be related to the initial conditions of the target.

International audience; Since the events of September 11, 2001, the possibility of an intentional act targeting the chemical process industry has become realistic. It is, therefore, a great concern to be able to predict the immediate consequences of such an act. This study is intended to improve our knowledge about the sequence of events that occurs when a high-speed bullet (>1000 m s−1) penetrates a vessel filled with toxic liquid. We find that, prior to liquid ejection, several well-defined phases occur, including the phenomenon known as the “hydraulic ram.” This paper focuses on projectile–target interactions and explains how the decay of projectile velocity is related to the initial conditions of the target.

International audience; The objective of this work is to improve the knowledge of the shock-to-detonation transition of nitromethane. The study is based on a spectral analysis in the range 0.3–0.85 µm, with a 28-nm resolution, during experiments of plane shock impacts on explosive targets at 8.6 GPa. The time-resolved radiant spectra show that the detonation front, the reaction products produced during the superdetonation, and the detonation products are semitransparent. The temperature and absorption coefficient profiles are determined from the measured spectra by a mathematical inversion method based on the equation of radiative transfer with Rayleigh scattering regime. Shocked nitromethane reaches at least 2500 K, showing the existence of local chemical reactions after shock entrance. Levels of temperature of superdetonation and steady-state detonation are also determined.

The objective of this work is to clarify the mechanism of shock to detonation of nitromethane by time‐resolved emission spectroscopy. This paper presents the experiments performed in the spectral range 0.3–0.85 μm. Experimental results provide several radiance values depending on wavelength and time that we compared to measurements of pyrometry previously performed. Determination of the temperature profile is treated from the resolution of the equation of radiative transfer by an inversion method. The case of the steady state detonation is considered here.