Scientific and Technical Aerospace Reports Volume 39 April 6, 2001

20010025048 Lawrence Livermore National Lab., Livermore, CA USA
Experimental Study of Low Amplitude, Long-Duration Mechanical Loading of Reactive Materials
Urtiew, Paul A., Lawrence Livermore National Lab., USA; Forbes, Jerry W., Lawrence Livermore National Lab., USA; JANNAF
19th Propulsion Systems Hazards Subcommittee Meeting; November 2000; Volume 1, pp. 297-308; See also 20010025025
Contract(s)/Grant(s): W-7405-eng-48; No Copyright; Avail: CPIA, 10630 Little Patuxent Pkwy., Suite 202, Columbia, MD
21044-3200 HC
Studies of the low amplitude, long-duration mechanical loading of reactive materials rely very heavily, on the experimental
data in general and in particular on the data obtained from gauges placed within the experimental test sample to measure accurately
the local changes of parameters of the investigated material. For a complete description of these changes taking place in a dynamically
loaded material one would like to know both the spatial and the temporal resolution of pressure, temperature, volume, wave
and mass velocity. However, temperature and volume are not easily attainable. Therefore, most of the in-situ work is limited to
measurements of pressure and both wave and mass velocities. Various types of these gauges will be discussed and their records
will be illustrated. Some of these gauges have limitations but are better suited for particular applications than others. These aspects
will also be discussed. Main limitation of most in-situ gauges is that they are built for one-dimensional application. However, some
work is being done to develop and use two-dimensional gauges. While these experiments are necessary to validate theoretical
models of the phenomenon, they can also provide sufficient amount of data to yield complete information on material characteristics
such as its equation of state (EOS), its phase change under certain loads and its sensitivity to shock loading. Processing of
these data to get important information on the behavior of both reactive and non-reactive materials will also be demonstrated.
Author
Experimentation; Amplitude Distribution Analysis; Reactivity; Acoustic Velocity; Pressure Measurement; Loads (Forces)
20010025049 Naval Surface Warfare Center, Indian Head Div., Indian Head, MD USA
Plastic Deformation and the Initiation of Explosives
Coffey, C. S., Naval Surface Warfare Center, USA; Namkung, J., Naval Surface Warfare Center, USA; Sharma J., Naval Surface
Warfare Center, USA; Edsall, D. W., Naval Academy, USA; JANNAF 19th Propulsion Systems Hazards Subcommittee Meeting;
November 2000; Volume 1, pp. 309-318; In English; See also 20010025025; No Copyright; Avail: CPIA, 10630 Little Patuxent
Pkwy., Suite 202, Columbia, MD 21044-3200 HC
The energy dissipated during plastic deformation of shocked or impacted explosive crystals has been suggested as the source
of the energy required to initiate chemical reaction in these materials. Previously the energy dissipation rate and the plastic
deformation rate in shocked or impacted crystals were determined and related to initiation of detonation. Here the plastic deformation
rate for initiation of reaction due to impact or mild shock is experimentally determined. This was done for a number of different
materials and compared with theoretical calculations for HMX and RDX crystals. This provides for the first time a measure
of the initiation response of explosives over the entire range of shock and impact for which the reactions occur.
Author
Plastic Deformation; Explosives; Energy Dissipation; HMX; Detonation
20010025050 Naval Surface Warfare Center, Energetic Materials Research and Technology Dept., Indian Head, MD USA
Use of Split Hopkinson Pressure Bar for Measuring High Strain-Rate Behavior of Energetic Compositions
Joshi, Vasant S., Naval Surface Warfare Center, USA; Lee, Richard J., Naval Surface Warfare Center, USA; JANNAF 19th Propulsion
Systems Hazards Subcommittee Meeting; November 2000; Volume 1, pp. 319-326; In English; See also 20010025025;
No Copyright; Avail: CPIA, 10630 Little Patuxent Pkwy., Suite 202, Columbia, MD 21044-3200 HC
The split Hopkinson pressure bar technique has been successfully used to characterize high strain-rate behavior (10(exp 3)
to 10(exp 4) 1/s) of metals in the past. Similar studies on energetic materials are desired to assist in developing a model that can
predict the mechanical response of energetic materials to various stimuli. Since the strength of these composite materials are far
lower than any metallic materials, their deformation characteristics must be fully understood before applying any data reduction
scheme successfully. High-speed-imaging techniques have been explored here to validate conventional strain gauge data for low
strength energetic materials.
Author
Strain Gages; Pressure Measurement; Metals; Deformation
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