Femtosecond laser interaction with energetic materials

Roos, E.; Benterou, Jerry; Lee, Ronald S.; Roseke, Frank; Stuart, B. C.

doi:10.1117/12.482111

Cited by 11 publications

(5 citation statements)

References 3 publications

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“…Up to date there are only a few reports on the employment of the femtosecond laser pulse in machining energetic materials, showing its feasibility 9,10 and non-involvements of heat transfer and chemical reactions 11,12 during the processes. By using ANSYS (large finite element analysis software), Chen and co-workers 14 have further established heat transfer models for the femtosecond laser in cutting propellant 13 and ablating Mg/polytetrafluoroethylene.…”

Section: Vol32mentioning

confidence: 99%

Molecular Dynamics Simulations of Femtosecond Laser Ablation of Energetic Materials

Yang¹,

北京理工大学²,

Liu³

et al. 2016

Acta Physico-Chimica Sinica

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To understand the physical and chemical responses of energetic materials, such as 1,3dinitrobenzene (DNB, C6H4N2O4), hexanitrohexaazaisowurtzitane (CL20, C6H6N12O12), and CL20/DNB co-crystal, to femtosecond laser ablation (FLA), their molecular reaction dynamics have been investigated using the ReaxFF/ lg force field. The computational results indicate that the temperature and pressure of the CL20/DNB system jump during FLA. In particular, the temperature and pressure gradually reach their maxima following an initial cooling process. N-NO2 bond breaking of the CL20 molecule triggers the reactions for both the CL20 and CL20/ DNB systems. However, the CL20 system prevails the CL20/DNB co-crystal in the decomposition rate simply because coexistence of DNB molecules in the mixture and generated decomposition products containing benzene rings greatly reduce the effective collision probability between CL20 and the products.

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Section: Vol32mentioning

confidence: 99%

Molecular Dynamics Simulations of Femtosecond Laser Ablation of Energetic Materials

Yang¹,

北京理工大学²,

Liu³

et al. 2016

Acta Physico-Chimica Sinica

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“…No visible evidence of a reaction was observed in the samples except in the cutting of LX-16 with a long pulse of 500 ps, which proved that an ultrashort laser duration is essential for the safe cutting and machining of explosive materials. Since then, fs-lasers have become widely used in the machining of energetic materials. − In the process of fs-laser ablation of explosives, after the strong absorption of photons, a critical density plasma is generated on a time scale that is shorter than the transfer of electron kinetic energy into the crystal lattice. The material in the irradiated zone can be directly converted from its initial solid state into the plasma with a critical density and be removed through the hydrodynamic expansion of the plasma.…”

Section: Introductionmentioning

confidence: 99%

Microscopic Mechanisms of Femtosecond Laser Ablation of HMX from Reactive Molecular Dynamics Simulations

Yang

et al. 2020

J. Phys. Chem. C

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With ultrashort duration and ultrahigh energy, femtosecond laser (fs-laser) pulses are very promising for the precision machining of energetic materials. Compared with the mechanical machining methods of energetic materials, fs-laser machining technology has the advantages of high safety, high precision, and absence of pollution. A deep understanding of the mechanisms between fs-lasers and energetic materials is the basis for the development of fs-laser machining technology. In this paper, the method of reactive molecular dynamics (ReaxFF-MD) was adopted to calculate the fs-laser ablation process of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX, a high explosive compound), and the ablation mechanisms of HMX under different fs-laser energies were studied. The results show that the fs-laser ablation mechanisms of HMX are related to the laser power density. When the laser power density is high enough (3.4 × 10 14 W/cm 2 , 1.0 mJ/pulse), HMX undergoes ionization or decomposition reactions at the picosecond level (∼7.65 ps) and produces a high temperature and pressure plasma. Many N, H, and O single atoms and their ionic products occur along with some small molecular fragments of NO 2 , H 2 O, CO 2 , N 2 , H 2 , NH, NH 2 , CO, OH, CNO 2 and very few toxic products of NO and HNO 2 . In this case, the removal process of HMX occurs via a phase explosion mechanism. As the laser energy decreases, the ionization degree of ablation products decreases, in which the number of monatomic and ionic products decreases, while the number of toxic small molecules (such as NO, HNO 2 , and HNO) increases. When the laser power density is relatively low (0.34 × 10 14 W/cm 2 , 0.1 mJ/pulse), the removal process of HMX occurs via a photomechanical mechanism, and the compound escapes as intact initial HMX molecules. When the laser power density is close to the ablation threshold of the explosive, the HMX molecules only undergo a melting state to some extent without escaping from the surface of the crystal. Therefore, the fs-laser can be used in the precise machining of explosives and preparation of highpurity energetic nanomaterials by a reasonable selection of fs-laser energy.

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“…such as solid propellants, dynamites and polymer-bonded explosives (PBXs). Several applications involve laser irradiation, such as remote laser-based detection [1][2][3][4][5], laser machining [6] and laserinduced ignition [7]. When subjected to high power density laser irradiation, extensive fracture, plastic deformation and localized hot spot formation occur in these energetic aggregates [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Behaviour of crystalline–amorphous interfaces in energetic aggregates subjected to coupled thermomechanical and laser loading

Brown

Zikry

2015

Proc. R. Soc. A.

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The behaviour of energetic aggregates was investigated for quasi-static compression and high strain rate thermomechanical compression behaviour that is coupled to laser irradiation. A dislocation-density-based crystal plasticity formulation was used to represent energetic crystalline behaviour, a finite viscoelastic formulation was used for the polymer binder and a coupled electromagnetic (EM)–thermomechanical computational scheme was used to predict aggregate response. Aggregates with different crystal sizes were considered to account for physically representative energetic microstructures and to understand the effects of crystal–crystal and crystal–binder interactions. The presence of smaller embedded crystals in the binder ligaments inhibited viscous sliding, and resulted in global hardening of the aggregate, which led to large stress gradients, localized plasticity and dislocation-density accumulation. The embedded crystals also increased scattering of the EM wave within the binder ligaments and increased the localization of EM energy and laser heat generation. Geometrically, necessary dislocation densities and stress gradients were calculated to characterize how hardening at the binder interfaces can lead to strengthening or defect nucleation.

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Femtosecond laser interaction with energetic materials

Cited by 11 publications

References 3 publications

Molecular Dynamics Simulations of Femtosecond Laser Ablation of Energetic Materials

Molecular Dynamics Simulations of Femtosecond Laser Ablation of Energetic Materials

Microscopic Mechanisms of Femtosecond Laser Ablation of HMX from Reactive Molecular Dynamics Simulations

Behaviour of crystalline–amorphous interfaces in energetic aggregates subjected to coupled thermomechanical and laser loading

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