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Your search keyword '"Duarte, Camilo A."' showing total 2 results
Start Over Author "Duarte, Camilo A." Topic friction
2 results on '"Duarte, Camilo A."'

1. Dynamic fracture and frictional heating due to periodic excitation in energetic materials.

Author

Duarte, Camilo A., Kohler, Rachel, and Koslowski, Marisol

Subjects
*FRACTURE mechanics, *FRICTION, *HEATING, *EXCITATION equipment, *MICROSTRUCTURE, *ENERGY dissipation
Abstract

Mechanical stimulus may lead to localized temperature increase due to the concentration of energy dissipation at microstructural features. Mechanically induced heating occurs, for example, when materials are subjected to periodic excitation. This is a particular concern in energetic materials where ignition may start a deflagration. In this study, finite element simulations are performed on a single β -HMX particle in a polymer matrix subjected to mechanical periodic excitation. Different initial defects, such as cracks and interface debonding, are included to control the location of hot-spots nucleation. The model accounts for damage evolution and heat generation due to friction at cracks. The results indicate that hot-spots nucleate preferentially at the particle/binder interface, and therefore, the temperature rate is higher when the particle is initially debonded than when it is perfectly attached to the polymer. [ABSTRACT FROM AUTHOR]

Published
2018
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2. Hot-spots in polycrystalline [formula omitted]-tetramethylene tetranitramine ([formula omitted]-HMX): The role of plasticity and friction.

Author

Duarte, Camilo A. and Koslowski, Marisol

Subjects
*FRICTION, *TRANSPORT equation, *SINGLE crystals, *EQUATIONS of state, *SURFACE cracks
Abstract

We study the effect of the crystalline anisotropy and the relative importance of plasticity and friction on the formation of hot-spots in polycrystalline and single crystal β -HMX when impacted at different weak shock strengths with particle velocities 0.1 km/s and 0.4 km/s. We use a continuum model for large deformations that includes an equation of state, single crystal plasticity, fracture evolution, and heat transport. Our results indicate that plastic dissipation creates heterogeneous temperature fields due to crystal anisotropy. At high shock strengths, the temperature due to frictional heating at crack surfaces becomes the critical hot-spot formation mechanism for the conditions and parameters studied here. Furthermore, the predicted temperature is more sensitive to changes in the friction coefficient than the Taylor–Quinney coefficient accompanying the plastic dissipation used in the thermal transport equation. [ABSTRACT FROM AUTHOR]

Published
2023
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