Hostname: page-component-7479d7b7d-m9pkr Total loading time: 0 Render date: 2024-07-13T12:42:28.549Z Has data issue: false hasContentIssue false

Fracture Surface Topography of Octol Explosives

Published online by Cambridge University Press:  15 February 2011

M. Yvonne D. Lanzerotfi
Affiliation:
U. S. Army Armament Research, Development and Engineering Center, Picatinny Arsenal, NJ 07806-5000
James J. Pinto
Affiliation:
U. S. Army Armament Research, Development and Engineering Center, Picatinny Arsenal, NJ 07806-5000
Allan Wolfe
Affiliation:
New York City Technical College, Brooklyn, NY 11201-0000
Get access

Abstract

Energetic materials are of significant interest for scientific and practical reasons in the extraction (mining) industry, space propulsion, and ordnance. The nature of the fracture process of such materials under high acceleration is of particular interest, especially in ordnance. This paper describes new experimental and analysis techniques that allow us to characterize quantitatively and to compare the fracture surfaces of different energetic materials, and to deduce the specific fracture mechanisms. The techniques are widely applicable to other composite systems. In the materials discussed herein, topographical profiles spaced 1.0 mm apart across the fracture surfaces of two types of Octol have been obtained with a diamond stylus profilometer. Spatial power spectra (wavelengths of 1.0 μm 1.0 cm) have been calculated using a prolate spheroidal data window in the horizontal space domain prior to using a fast Fourier transform algorithm. The spatial power density of the fracture surface profiles is found in general to decrease with increasing spatial frequency over the region of interest, ≈ 1 mm-1 to ≈ 1 cm-1. Quasi-periodic peaks corresponding to HMX particle sizes are observed in the Octol spatial power spectra. These peaks indicate the inhomogeneous HMX grain size distribution in the Octol fracture surfaces. Peaks in the Octol spectra indicate that intergranular fracture often occurs between the TNT and HMX grains. Fractal analysis of the Octol power spectral slopes indicates the regions of deterministic, intergranular failure and the regions of the nondeterministic, trans-granular failure through TNT or HMX grains. This non-deterministic (fractal) failure is chaotic and may indicate the origin of failure in the sample.

Type
Research Article
Copyright
Copyright © Materials Research Society 1993

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Lanzerotti, M. Y. D. and Sharma, J., App. Phys. Lett. 39 (1981) 455.Google Scholar
2. Lanzerotti, M. Y. D., Pinto, J. and Wolfe, A., “Broad Bandwidth Study of the Topography of the Fracture Surfaces of Explosives”, in The Ninth Symposium (International) on Detonation Volume 1, pp. 355361, 28 August - 1 September 1989, Portland OR.Google Scholar
3. Lanzerotti, M. Y. D., Pinto, J., and Wolfe, A., “Fracture Surface Topography of Cast TNT”, in Shock Waves in Condensed Matter, 1991, eds. Schmidt, S.C., Dick, R.D., Forbes, J. W., Tasker, D. G. (1992 Elsevier Science Publishers B. V., Amsterdam, The Netherlands) pp. 575–8.Google Scholar
4. Lanzerotti, M. Y. D., Pinto, J., Wolfe, A., and Thomson, D.J., “Power Spectral Characterization of Fracture Surfaces of TNT, Composition B, and Octol”, 1992 Army Science Conference, Kissimmee, FL, 22–25 June 1992, in press.Google Scholar
5. Bowden, F. P. and Joffe, A. D., Initiation and Growth of Explosion in Liquids and Solids (Cambridge University Press, 1952).Google Scholar
6. Thomson, D. J., Spectral Analysis of Short Series, Ph. D. Dissertation, Department of Electrical Engineering, Polytechnic Institute of Brooklyn, Brooklyn NY, 1971.Google Scholar
7. Thomson, D. J., Proc. IEEE, 70, 1055 (1982).Google Scholar
8. Thomson, D. J., et al. , Physics of the Earth and Planetary Interiors, 12, 217 (1976).Google Scholar
9. HMX, MIL-H-4544B (PA), 27 February 1974.Google Scholar
10. Brown, S. R. and Scholz, C. H., J. Geophys. Rev. 90, 12,575 (1985).Google Scholar
11. Hough, S. E., Geophys. Res. Lett. 16, 673 (1989).CrossRefGoogle Scholar
12. Mandelbrot, B. B., The Fractal Geometry of Nature (Freeman, NY, 1983).Google Scholar
13. Mandelbrot, B. B., Physica Scripta, 32, 257 (1985).CrossRefGoogle Scholar
14. PIC Material Specification for Sedimentation Cast Octol, 1986.Google Scholar