Инициирование детонации световым импульсом в тонком заряде пиротехнического состава ВС-2

The paper presents the results of the initiation of film charges of pyrotechnic composition VS-2 by flash lamps. It is shown for the first time that the pulsed radiation of flash lamps causes detonation in the film of composition VS-2, the velocity of which is ~ 4300 m / s, and in the aluminum witness plate, deformation, the depth of which depends on the thickness of the film charge of composition VS-2.

Dynamic Tests for Energy Absorption by Selected Auxetic Fabrics

Experimental dynamic tests for energy absorption by four selected auxetic fabrics were conducted and analyzed. An original test stand was designed, manufactured and attached to a Hopkinson's bar. The energy absorbed by an auxetic curtain was expressed in terms of the energy of the maximum elastic deformation of a unit volume along the support line of the witness-plate. A quasi-impulse load was induced using a gas blast under a pressure corresponding to an indoors deflagration explosion of a propane-air mixture in a vented room. The auxetic fabric with the best energy-absorption properties was identified on the basis of the comparative analysis using a reference system with a steel specimen.

High Velocity Uniaxial Strain Response of ERG Aerospace Aluminum Foam

We report the results of uniaxial strain experiments of ERG Aerospace aluminum foam, at 50% relative density up to 10 GPa. The reverse ballistic plate reverberation technique was used to obtain shock compression states of the material. In these tests, 6061 T-6 aluminum, oxygen free homogenous copper (OFHC), and tantalum were used as standard material targets and were shocked by an aluminum foam projectile traversing up to 2.0 km/s. The response of the target plates were monitored by three different velocity interferometers positioned at three different locations on the witness plate. This provided us with the compaction behavior of the foam material in three discrete locations per sample, due to the presence of porosity in the foam material.

DESENSITIZATION OF HETEROGENEOUS HIGH EXPLOSIVES UNDER INITIATION THROUGH HIGH MODULUS ELASTIC ELEMENTS

We have experimentally investigated the influence of fluoroplastic, copper, and silicon carbide inert inserts on the process of detonation transmission through water. Active and passive HE charges were molded from high explosive (HE) Comp. B. The diameter and height of HE cartridges were 40 and 40 mm, respectively. On the rear end of the passive HE charge a steel witness plate was mounted, which detected presence or absence of detonation. Inert inserts were shaped as 20 mm × 20 mm square prisms of varying lengths, and were contained between active and passive HE charges without any clearance on the way of initiating shock wave with partial overlap of HE cross sections. We demonstrate that preloading a passive HE charge with a shock wave transmitted through a copper or a ceramic insert causes considerable desensitization of the Comp. B. Other conditions being the same, the crash distance of detonation transmission for copper was equal to 74%, and for silicon carbide – to 60% of the distance for fluoroplastic. This desensitization phenomenon may be used for development of protective shells for HE. While performing experiments with 20 mm ceramic inserts we have observed unknown cumulation phenomenon, which manifested itself as a hole in identification steel specimen with depth of about 10 mm.

Measurement of Molecular Film Contamination Using Surface Acoustic Wave Microbalances

To ensure the cleanliness of sensitive spacecraft systems, the contamination environment in aerospace cleanrooms and highbays is closely monitored. In this paper, we report the testing and evaluation of a commercially available molecular contamination monitor consisting of a 200-MHz surface acoustic wave microbalance (SAWM). SAWMs were placed into four different aerospace facilities with markedly different environments. SAWMs measured distinctly different molecular film accretion rates consistent with the levels of contamination control and activity in each facility. SAWM results were compared with nonvolatile residue (NVR) accretion rates measured by witness plates. Witness plate data yielded a higher NVR accretion rate than microbalance data. We present evidence that this difference is due to the detection limit of the witness plate analysis technique and not to a fundamental difference in surface deposition processes.