1. The irreversible thermal expansion of an energetic material
- Author
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François Rabette, Maxime Biessy, François Willot, Hervé Trumel, Thomas Peyres, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de Morphologie Mathématique (CMM), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), CEA, DAM, Le Ripault, F-37260 MONTS, France, and MINES ParisTech - École nationale supérieure des mines de Paris
- Subjects
FFT-based homogenization ,internal stresses ,Materials science ,polymer plasticity ,Atmospheric temperature range ,Plasticity ,Energetic material ,Thermal expansion ,chemistry.chemical_compound ,[SPI]Engineering Sciences [physics] ,Thermoelastic damping ,Brittleness ,chemistry ,TATB ,Residual stress ,thermoelastic anisotropy ,glass transition ,Composite material ,polycrystal ,thermal expansion ,microcracking - Abstract
The work deals with a macroscopically isotropic energetic material based on triamino-trinitrobenzene (TATB) crystals bonded with a small volume fraction of a thermoplastic polymer. This material is shown experimentally to display an irreversible thermal expansion behavior characterized by dilatancy and variations of its thermal expansion coefficient when heated or cooled outside a narrow reversibility temperature range. The analysis of cooling results suggests the existence of residual stresses in the initial state, attributed to the manufacturing process. Microstructure-level FFT computations including the very strong anisotropic thermoelastic TATB crystal response and temperature-dependent binder plasticity, show that strong internal stresses develop in the disoriented crystals under thermal load, either heating or cooling. Upon cooling, binder plastic yielding in hindered, thus promoting essentially brittle microcracking, while it is favored upon heating. Despite its low volume fraction, the role of the binder is essential, its plastic yielding causing stress redistribution and residual stresses upon cooling back to ambient.
- Published
- 2021
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