SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-161 (AirForce)
Title:  Imaging Penetration in Geologic Materials
Research & Technical Areas:  Weapons

  Objective:  Develop the techniques and equipment necessary for imaging trajectory deviation and cavity creation phenomena during penetration events in geologic materials.
  Description:  There exists a need, critical to national defense, for understanding the mechanisms that affect penetrator trajectories during penetration through clay, silt, sand, and soil at impact velocities of 1,500 to 4,000 feet per second. Scaled experimentation has shown penetrator instabilities in such media at such velocities, but we lack the understanding of this phenomenon. At present we can predict trajectory deviation and cavity creation in such media using physics based models. However, confirmation of these predictions is difficult because no current techniques or equipment are capable of imaging such events. Current techniques only provide static, two dimensional images and are limited by the thickness of the target material between the x-ray and the penetrator. The current need is to image, in real-time, the trajectory deviation and cavity creation during penetration of a sand/soil target at high velocity. The goals of this effort will be 1) To investigate new and innovative concepts, techniques, and equipment for imaging a penetrator as it moves through various media 2) To develop the selected concepts, techniques, and equipment 3) To demonstrate through testing that they are technically and financially feasible, and produce accurate images of the penetration event in the media specified 4) To evaluate the technical risk associated with each proposed technique 5) To develop the methodology for proposed concepts and equipment, data reduction techniques, test requirements, and control parameters 6) To provide a hierarchy of recommendations 7) To perform scaled penetration tests which evaluate the most capable and reliable techniques and 8) To document all aspects of the effort, to include test data, which will be used in support of analytical, computational, and theoretical model development. Approaches to the problem are not limited to any specific means of investigation. It is understood that various techniques may work in some media but not others. This is acceptable, so long as there is a method for each of the mediums of interest. Having a reliable technique for imaging soil penetration events in real time will provide immense insight into the dynamic response of various penetrating weapon systems. This insight will allow researchers to develop the technology required to reduce trajectory deviation and adverse cavity creation effects. Improved penetration technologies will directly contribute to the effectiveness of major Air Force weapon systems.

  PHASE I: Develop the proposed techniques, methods, and equipment. Demonstrate through testing that they are technically and financially feasible, and produce accurate images of the penetration event in the media specified. Evaluate the technical risk associated with each proposed technique.
  
  PHASE II: Develop the methodology for proposed concepts/equipment, data reduction techniques, test requirements, and control parameters. Provide a hierarchy of recommendations. Techniques which provide the most capability and best reliability will be developed for use in scaled penetration tests through varieties of media. Resulting data will be used in analytical, computational, and theoretical models.

  DUAL USE COMMERCIALIZATION: Military application: Military applications include more accurate bombs, penetrators, sub-munitions, warheads, projectiles, etc. Commercial application: Commercialization uses include petroleum exploration and recovery, mining measurements, and tool development.

  References:  1. Forrestal, M. J., and Luk, V. K., “Penetration into Soil Targets,” International Journal of Impact Engineering, 1992, Vol. 12, pp. 427-444. 2. Westine, P. S., “Mechanics of Soil Penetration,” AMD (Symposia Series) (American Society of Mechanical Engineers, Applied Mechanics Division), 1985, Vol. 69, pp. 69-94. 3. Fosanella, E.L., Knight, N.F., and Kellas, S. “Low Velocity Earth Penetration Test and Analysis,” AIAA paper 200H388, 2001. 4. Elwell, J., “GPS/INS Guidance of Terradynamic Penetrators,” AIAA paper 97-3553, August 1997.

Keywords:  Sand penetration, soil penetration, geological penetration, cavity creation due to penetration, trajectory, trajectory control, munition

Questions and Answers:
Q: 1. I assume that proper scaling of the experiment down to say 1/2" projectiles is permissible?
A: Yes, scaling of projectiles down to 1/2" diameter (50 Caliber) projectile is permissible for early phases of development as long as the technology used can be shown to have potential to scale up to a full size weapon test. In order to verify the scientific data gathered, at some point tests would need to be done on a full size weapon to validate that the information learned is applicable to warhead research. We prefer to use projectiles of 1" diameter, as this would correspond to our databases, but understand it may not be initially economical.
Q: 1. I assume that proper scaling of the experiment down to say 1/2" projectiles is permissible?
A: Yes, scaling of projectiles down to 1/2" diameter (50 Caliber) projectile is permissible for early phases of development as long as the technology used can be shown to have potential to scale up to a full size weapon test. In order to verify the scientific data gathered, at some point tests would need to be done on a full size weapon to validate that the information learned is applicable to warhead research. We prefer to use projectiles of 1" diameter, as this would correspond to our databases, but understand it may not be initially economical.

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