Apparatus and method for producing fragment-free openings

• US 6,220,166 B1
• Filed: 08/02/1999
• Issued: 04/24/2001
• Est. Priority Date: 08/02/1999
• Status: Expired due to Term

• Current Assignee: National Technology & Engineering Solutions Of Sandia LLC (Honeywell International Inc.)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Cherry, Christopher R.
• Primary Examiner(s): TUDOR, HAROLD JAY
• Application Number:
  US09/365,655
• Time in Patent Office: 631 Days
• Field of Search: 86/49, 86/50, 102/303, 102/305, 102/306, 102/311, 102/312, 102/701, 102/293, 102/307-310, 102/475, 102/378, 72/55, 72/56, 724/30, 727/06, 588/202, 588/203, 89/11.4
• US Class Current: 102/305
• CPC Class Codes: F42B 33/06 Dismantling fuzes, cartridges, projectiles, missiles, rockets or bombs F42B33/004 and F42B33/04 take precedence; elimination of undesirable components of explosives C06B21/0091
• CPC Class Codes: F42B 33/062 by high-pressure water jet means
• CPC Class Codes: F42D 3/00 Particular applications of blasting techniques explosive welding B23K20/08; explosive bolts or actuators F42B3/006; explosive valves F16K13/06; cutting devices actuated by explosion B23D15/145; pyrotechnical actuators F15B15/19; switching devices actuated by explosion H01H39/00
• CPC Class Codes: Y10S 102/701 Charge wave forming
• CPC Class Codes: Y10S 72/706 Explosive

Abstract

An apparatus and method for explosively penetrating hardened containers such as steel drums without producing metal fragmentation is disclosed. The apparatus can be used singularly or in combination with water disrupters and other disablement tools. The apparatus is mounted in close proximity to the target and features a main sheet explosive that is initiated at least three equidistant points along the sheet'"'"'s periphery. A buffer material is placed between the sheet explosive and the target. As a result, the metallic fragments generated from the detonation of the detonator are attenuated so that no fragments from the detonator are transferred to the target. As a result, an opening can be created in containers such as steel drums through which access to the IED is obtained to defuse it with projectiles or fluids.

Claims

1. An apparatus for creating an opening in a barrier, comprising:

a) an explosive charge secured to a support;

b) a buffer material on said support and disposed between said charge and the, barrier wherein the buffer material is adapted to be mounted on the barrier,

c) means for setting off said explosive charge and creating an explosive force, wherein said explosive force causes the barrier to fail from an initial point and along intersecting failure lines thus defining a plurality of petals cantilevered from the barrier which are pushed by said explosive force to define a fragment-free opening in the barrier.

2. The apparatus of claim 1, wherein said explosive is in sheet form.

3. The apparatus of claim 2, wherein said means sets off said sheet at at least three locations.

4. The apparatus of claim 3, wherein said detonating means sets off said locations on said sheet at substantially the same time.

5. The apparatus of claim 4, wherein said locations are substantially equidistant from each other.

6. The apparatus of claim 3, wherein said locations are substantially equidistant such that when said explosive charge is set off, the barrier fails from a starting point equidistant from said locations and along failure lines that extend from said point toward said locations, thus defining a plurality of triangular, cantilevered petals which are pushed by said explosive force to define a fragment-free opening in the barrier.

7. The apparatus of claim 1, wherein said support is made substantially from a shock-attenuating material.

8. The apparatus of claim 7, wherein said material for said support comprises foam.

9. The apparatus of claim 2, wherein said buffer material extends to at least the dimension of said sheet and further comprises a shock-attenuating material.

10. The apparatus of claim 9, wherein said buffer material comprises foam having an adhesive material on a face thereof to facilitate attaching said apparatus to the barrier.

11. The apparatus of claim 1, wherein said opening is polygonal or round in shape formed by substantially triangularly shaped petals which are pushed by said explosive force to create the opening in the barrier.

12. The apparatus of claim 1, wherein said opening created by setting off said explosive charge is greater than the size of said support.

13. The apparatus of claim 1, wherein said means for setting off the explosive material further comprises an explosive transfer device connected to a plurality of strips which in turn are operably connected to at least three discrete locations on said explosive charge.

14. A method of making a fragment-free opening in a barrier, comprising:

a) securing an explosive to a buffer material;

b) securing the buffer material to the barrier;

c) setting off the explosive and creating an explosive force; and

d) creating an opening in the barrier by failing the barrier along intersecting lines of failure with the explosive force into a plurality of petals that remain attached to the barrier after displacement to define the opening.

15. The method of claim 14, further comprising:

a) using sheet explosive;

b) setting off said sheet explosive in at least three locations.

16. The method of claim 15, further comprising spacing said locations equidistant from each other.

17. The method of claim 14, further comprising:

a) encasing said sheet explosive with a shock-attenuating material;

b) supporting a detonating device in said attenuating material which branches to each of said locations on said sheet;

c) providing foam as a buffer between said sheet and the barrier.

18. A method of forming a fragment-free opening in a barrier, comprising:

a) initiating an explosive material mounted on the barrier and creating shock pressure;

b) creating at least two intersecting fracture plane in the barrier with the shock pressure; and

c) propagating fractures in the barrier along the intersecting fracture planes to form a plurality of cantilevered petals defining an opening in the barrier.

19. The method of claim 18, further including attenuating the shock pressure with shock attenuating material interposed between the explosive material and the barrier.

20. The method of claim 19, wherein the attenuated shock pressure limits fracturing of the barrier along the periphery of the explosive material.

21. The method of claim 18, further including forming a plurality of triangular shaped petals in the barrier wherein the apexes of the petal intersect at the point of intersection of the fracture planes.

22. The method of claim 18, further including bending the petals in the direction of propagation of the shock pressure starting at the apex of each petal without detaching the petal from the barrier.

23. The method of claim 18, further including attenuating the velocity of bending of the petals by attenuating the shock pressure with a shock attenuating material interposed between the explosive material and the barrier, whereby the petals remain attached to and cantilevered from the barrier.

24. An apparatus for creating a fragment-free opening in a barrier, comprising:

a) an explosive charge;

b) shock attenuating material encapsulating all but one surface of the explosive charge;

c) a buffer material mounted on the one surface of the explosive charge not encapsulated with shock attenuating material;

d) adhesive means with the buffer material for mounting the apparatus on the barrier;

e) means for setting off the explosive charge and creating an explosive force, wherein the explosive force creates intersecting lines of failure in the barrier whereby the barrier fails from an initial point and along the intersecting failure lines thus forming petals cantilevered from the barrier and defining an opening therein.

25. An explosive apparatus for creating a fragment-free opening in a barrier, comprising:

a) a shock absorbent;

b) an explosive material mounted with the shock absorbent;

c) a shock buffer mounted with the explosive material having an adhesive surface adapted for attaching the apparatus to the barrier such that the shock buffer is interposed between the explosive material and the barrier; and

d) a detonator mounted in the shock absorbent and configured so as to set off the explosive material at at least three locations wherein intersecting planes of fracture are created in the barrier by the shock pressure from the detonated explosive material thus forming petals cantilevered from the barrier and defining an opening therein.