The elastic constants and related properties of the energetic material cyclotrimethylene trinitramine (RDX) determined by Brillouin scattering

Abstract

Haycraft, James J.; Stevens, Lewis L.; and Eckhardt, Craig J., "The elastic constants and related properties of the energetic material cyclotrimethylene trinitramine (RDX) determined by Brillouin scattering" (2006 The acoustic phonons of cyclotrimethylene trinitramine ͑RDX͒ have been studied using Brillouin scattering. The analysis of the acoustic-phonon velocities allowed determination of the complete stiffness tensor for this energetic material. The results are compared to other recent experimental and theoretical determinations of the RDX elastic constants, bulk moduli, and shear moduli. The observed ordering of elastic constants, C 11 Ͼ C 22 Ͼ C 33 , is qualitatively associated with a ͑001͒ cleavage plane and molecular packing. This interpretation is further corroborated by the linear compressibilities plotted in three crystallographic planes, and a comparison to recent theoretical and experimental hydrostatic compression studies on RDX. Finally, the elasticity of RDX is compared to a recently published report on the beta polymorph of cyclotetramethylene tetranitramine's elasticity, and is related to several proposed mechanisms for detonation initiation.

Nanomechanics of RDX Single Crystals by Force–Displacement Measurements and Molecular Dynamics Simulations

“…29 The constants comprise two data sets reflecting the softest and stiffest reported experimental values, obtained by resonant ultrasonic (RUS) and Brillouin scattering methods, respectively. 15,16 The RUS values are in reasonable agreement with the more recent RUS values reported previously by Schwarz and co-workers, and they are in line with those obtained by Sun and co-workers using impulsive stimulated thermal scattering. 17,18 We note recent Brillouin measurements by Bolmer and Ramos show agreement with previous experimental results, except those from the previous Brillouin scattering measurements.…”

Density functional theory calculations of anisotropic constitutive relationships in alpha-cyclotrimethylenetrinitramine

“…In particular, the bulk modulus has been reported 3,4,8 by fitting hydrostatic P-V data to various EOS forms. In addition, the elastic constants, bulk moduli, and shear moduli have been measured experimentally using a sound-propagation technique, 10 Brillouin scattering, 11 and resonant ultrasound spectroscopy. 12 Sewell…”

“…Table II shows the results of our calculations compared with the experiment. 3,4,8,[10][11][12] Note that calculation of the bulk modulus via the methods of Voigt and Reuss requires the elastic constants of the material. 33 The values reported for the bulk modulus from experiment range from 9.8 to 13.9 GPa, and our results are within this range for each of the three fitting forms above.…”

Hydrostaticity of poly(methyl methacrylate) loaded in a diamond anvil cell for high-pressure study

“…On the other hand, if polymeric materials are to be investigated, they may be put into the gasket hole without any pressure medium. This method has been used to measure the EOS of several polymeric materials up to a few tens of GPa [6][7][8][9][10][11][12], for example, ~85 GPa for the Kel F-800 copolymer by using Brillouin scattering spectroscopy [9]. However, a recent Brillouin scattering study on polycarbonate seems to indicate that the condition of hydrostatic pressure may be seriously broken for the polymer once it is included in the DAC without any pressure medium [13].…”

“…The EOS of polymers relates the density to the pressure. The EOS can be derived from the sound velocity, which can be calculated from the Brillouin frequency shift [6][7][8][9][10][11][12][13]. Since the Brillouin frequency shift is the only necessary information for the calculation of EOS, the same Brillouin shift under different M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 experimental conditions guarantees the same EOS of the materials loaded in DAC.…”