At the special conditions of loading a small part of the torrent of explosion accelerated powder (dispersed) particles can penetrate into metal barriers on depth, in 100 - 1000 time superior the size of particles. The phenomenon is known as effect of superdeep penetration (SDP). Following conditions are necessary for SDP: the speed of particles is not less than 300 m/s; the sizes of particles is less than 500 microns; the time of loading is more than 100 ms; the average density of torrent is more than 1 g/sm3.
New physical model of the effect of superdeep penetration (SDP) has been created. The model allows to explain the mechanism of SDP and to get mentioned above experimentally stated conditions of the phenomenon. The model is based on description of shock-wave interaction between the penetrating particles and target material.
Under the action of fluctuating field of stresses the mobile cavities in target material are appear. Such mobile cavities (transport capsules) carry the particles inside of target. The carried particle is passively moving in the capsule and does not spend energy for the deformation of a material.
The following criterion of a possibility of SDP is obtained:
where h is the height of a layer of powder particles in an explosive booster, Δt is the duration of loading, c is the velocity of sound.
According to this criterion, the penetration of particles can occur if h/Δt > 5*10-2 mm/μs, that corresponds to the torrent density ρ >1g/sm3.
It is established, that the value of characteristic time of process is proportional to diameter of particles. For the diameter of particles more than 500 microns this value exceeds the time value of a plastic relaxation of metals. In this case the target is deformed plastically; the transport capsules does not arise.
This work has been support by RFBR (grant No. 03-03-33028).