Method of designing an RPG shield

• US 8,453,552 B2
• Filed: 08/16/2011
• Issued: 06/04/2013
• Est. Priority Date: 04/16/2008
• Status: Active Grant

• Current Assignee: Foster-Miller Incorporated (Thermo Fisher Scientific Incorporated)
• Original Assignee: QinetiQ North America Incorporated (QinetiQ Group PLC)
• Inventors: Farinella, Michael, Lawson, William, Quigley, Scott, Curran, Robert
• Primary Examiner(s): Hayes, Bret
• Assistant Examiner(s): FREEMAN, JOSHUA E
• Application Number:
  US13/136,991
• Publication Number:
  US 20120046916A1
• Time in Patent Office: 658 Days
• Field of Search: 89 3601- 3617, 109/49.5, 114/241, 296/187.07
• US Class Current: 89/36.08
• CPC Class Codes: F41H 5/013 Mounting or securing armour plates
• CPC Class Codes: F41H 5/023 Armour plate, or auxiliary armour plate mounted at a distance of the main armour plate, having cavities at its outer impact surface, or holes, for deflecting the projectile
• CPC Class Codes: F41H 5/026 Slat armour; Nets
• CPC Class Codes: F41H 7/04 Armour construction in general F41H5/00

Abstract

A method of designing an RPG. A computerized model is created of a shield mesh opening with lines of a net intersecting at nodes and with hard points positioned at least at select nodes. The effectiveness of the mesh opening at a plurality of obliquity angles is determined. In the model, a change is made to the size of the mesh opening and the effectiveness is determined again at a plurality of different obliquity angles. Iterations of this process allow an optimal mesh opening size to be determined for a threat such as an RPG.

Claims

1. A method of designing a shield, the method comprising:

creating a computerized model of a shield mesh opening defined by intersecting lines of a net defining nodes with hard points positioned at least at select nodes;

determining the effectiveness of the mesh opening at a plurality of obliquity angles;

in the model, changing the size of the mesh opening and determining the effectiveness of said mesh opening at a plurality of obliquity angles; and

choosing a mesh opening size based on said determinations.

2. The method of claim 1 in which the computerized model includes a plurality of different effectiveness zones.

3. The method of claim 2 in which a first said zone is proximate the nodes and a second said zone is centrally located in the mesh opening.

4. The method of claim 3 in which a third said zone is between the second and first zones.

5. The method of claim 3 in which the second said zone is a function of a critical cone diameter of an RPG before which, if a hard point engages the RPG cone, the effectiveness is high and after which, if a hard point engages the RPG, the effectiveness is lower.

6. The method of claim 2 in which the effectiveness zones change shape as a function of the obliquity angle.

7. The method of claim 1 in which choosing a mesh size includes optimizing the mesh size for different obliquity angles.

8. A method of designing an RPG shield, the method comprising:

creating a computerized model of an RPG shield mesh including intersecting lines of a net creating nodes with a hard point positioned at least at select nodes;

using the model to determine the effectiveness of a plurality of mesh sizes for a plurality of RPG obliquity angles; and

choosing a mesh size based on said determination.

9. The method of claim 8 further including the step of determining a critical cone diameter for an RPG and using the critical cone diameter in the model to determine the effectiveness of said plurality of mesh sizes for a plurality of obliquity angles.

10. The method of claim 8 in which determining includes, for each mesh size, establishing percentages of the mesh area which would result in an RPG detonation, a high likelihood of defeat of an RPG, and a lower likelihood of defeat of an RPG.

11. The method of claim 8 in which the obliquity angles include a number of horizontal obliquity angles and a number of vertical obliquity angles.

12. The method of claim 8 further including fabricating a net with hard points as modeled and having a mesh size as chosen.

13. The method of claim 8 in which the mesh size chosen is between 110 and 130 mm.

14. The method of claim 9 in which determining the critical cone diameter includes evaluating a location on the RPG wherein, between a tip of the RPG and said location, an impact by a hard point results in a predetermined effectiveness and, at locations beyond said location, an impact by a hard point results in an effectiveness less than said predetermined effectiveness.

15. A method of choosing a mesh size for an RPG shield, the method comprising:

determining, for an RPG nose cone, a critical cone diameter wherein, between a tip of the RPG and said critical cone diameter, an impact by a hard point results in a predetermined effectiveness and, at locations beyond said critical cone diameter, an impact by a hard point results in an effectiveness less than said predetermined effectiveness;

choosing an initial mesh size based at least in part on the critical cone diameter, determined in laboratory experiments;

for the chosen net mesh size, at several vertical and horizontal obliquity angles, estimating a percentage of the mesh area which would result in an RPG detonation, a high likelihood of defeat of an RPG, and a lower likelihood of defeat of an RPG; and

choosing at least one additional net mesh size and performing said estimating step for said mesh size to optimize the mesh size for different obliquity angles.

16. The method of claim 15 in which determining the critical cone diameter includes firing an RPG or surrogate RPG at a net with spaced hard points and evaluating whether the RPG was defeated depending upon where on the nose cone a hard point impacted the RPG.