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Publication numberUS3820461 A
Publication typeGrant
Publication dateJun 28, 1974
Filing dateFeb 20, 1970
Priority dateFeb 20, 1970
Also published asDE2107102A1
Publication numberUS 3820461 A, US 3820461A, US-A-3820461, US3820461 A, US3820461A
InventorsD Silvia
Original AssigneeD Silvia
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Initiation aimed explosive devices
US 3820461 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Silvia June 28, 1974 I INITIATION AIMED EXPLOSIVE DEVICES [76] Inventor: Denis A. Silvia, 7 Shalimar Dr.,

Shalimar, Fla. 32579 [22] Filed: Feb. 20, 1970 [21] Appl. No.: 13,237

[52] US. Cl. 102/22, 102/100 [51] Int. Cl F421! 3/00 [58] Field of Search 102/22, 24 R, DIG. 2, 67,

[56] References Cited UNITED STATES PATENTS 2,999,458 9/1961 Coursen.... 102/22 3,016,831 l/1962 Coursen.... 102/22 3,035,518 5/1962 Coursen 4 102/22 3,170,402 2/1965 Morton et al..... 102/DIG. 2 3,280,743 10/1966 Ruether l02/DIG. 2 3,311,055 3/1967 Stresau, Jr. et a1. 102/22 3,430,564 3/1969 Silvia et al. 102/22 3,435,763 4/1969 Lavine l02/DIG. 2

3,447,463 6/1969 Lavine 102/67 3,490,372 l/l970 Lavine 3,598,051 8/1971 Avery 102/23 FOREIGN PATENTS OR APPLICATIONS 1,138,654 1/1969 Great Britain 102/D1G. 2

Primary Examiner-Robert F. Stahl Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn and Macpeak ABSTRACT The detonation of charge-around-case explosive devices is accomplished by combinations of initiation logic, detonation wave interactions, controlled case forming implosion and analog-to-digital methods of path control to enhance the directionality, projection of kill mechanism and environmental coupling of the charge in a variety of warhead/target intercept conditions. Numerous variants are developed to give a wide choice of geometries and complexity.

19 Claims, 52 Drawing Figures 'PATENTEDJUN281H74 3 820 461 SHEEY 1 [IF 9 I I ATTORNEYS PATENTl-imunza m4 SHEET 3 UF 9 FATENTED JUN 2 8 IBM SHEEY S [If 9 PATENTEDJUH 28 1974 SHEET 7 BF 9 zzzzzzzzf INITIATION AIMED EXPLOSIVE DEVICES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to explosive charges and more specifically to arrangements of explosive, case and buffer materials for initiating and controlling the detonation thereof to improve the directionality and/or coupling to case and environment. New initiation and buffering techniques have been developed to accomplish this.

2. Prior Art In the past warheads were usually formed of a metal case filled with a homogeneous mass of explosive which was isotropically detonated so that the fragments of the metal case would be propagated along a path substantially normal to the local surface of the warhead. At the most, the fragments could be deflected about 7 from normal and since the fragments were moving outwardly in all directions it was impossible to obtain any concentration of the fragments to provide a more effective fragmentation pattern in any specific direction. Most conventional warheads do not impact the target directly but encounter the target along one side or the other. When a warhead explodes the target subtends only a small angle about the warhead center. Making allowance for fuse inaccuracies, the target distribution will generally extend about 17/4 radians about a side- Iooking cylindrical warhead. Thus, more than half the case fragments are directed away from the target, even with maximum aiming in a case-around-charge design.

With the inability of assymetric initiation techniques to substantially improve kill-mechanism efficiency, several variable geometry approaches have been tried. These methods attempt to re-orient the warhead componentsjust prior to detonation. Unfortunately, certain difficulties militate against this method. Rapid deployment in a high speed air stream creates impossible aerodynamic problems and even the fastest mechanical movement has proven too slow in high speed intercept conditions.

Current fuse technology uses a variety of sensors to detect and track the target distribution centroid. The fuse initiates the warhead at achievement of the optimum geometric relationship vis-a-vis the target. Sidelooking air-air fuses which locate not only the polar but the azimuthal target coordinate sector as well have been successfully tested. These fuses give the warhead two pieces of information, namely when to detonate and what direction to aim. Because of the primitive state of explosive control prior to the present invention,

these fuses have been designed to communicate with parallel logic to the warhead. For example an eight-way aiming warhead would require eight detonators, each with a safe-arming mechanism. The fuse would choose the appropriate detonator to fire.

SUMMARY OF THE INVENTION i the appropriate aim direction. Any number of aim directions may be selected by serial coding (time sequencing) only two detonators.

The present invention also comprises numerous single point, sequenced, muIti-point and line initiation methods which are adaptable to realistic warhead packages and which operate in conjunction with the secondary explosive network means.

The present invention further comprises analog-to digital conversions of the detonation of the warhead explosive mass to provide control of the effective detonation velocity.

The present invention also comprises a unique means of using the sacrificial explosive itself as an incendiary/- reactive kill-mechanism. Generalization of this concept allows variable C/M (charge mass/metal mass) constructions.

Various combinations of the above features may be made to provide an improved warhead construction.

The present invention provides an improved arrange ment of the explosive, case and buffer materials for use with the above network means, initiation methods and detonation velocity control to provide a more effective warhead with a more efficient concentration of fragmentation and a more effective utilization of the explosive force.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the fragmentation of a conventional prior art warhead.

FIG. 2 (ad) shows the explosive sequence for a cylindrical warhead having the charge surrounding a casing with insufficient velocity of collapse to achieve ejection from the surround.

FIG. 3 (a-d) shows the explosive sequence according to the present invention for a cylindrical warhead hav ing the charge surrounding the liner, the liner being thin enough to achieve ejection.

FIG. 4 (a-c) schematically shows several conceptual modified arrangements for the explosive material to effectively extend the path of the explosive detonation around the periphery on the cylindrical charge.

FIG. 5 shows another embodiment of the present invention wherein a ring charge is utilized to detonate at least one explosive charge located radially outwardly thereof.

FIG. 6 is a schematic view showing the problem encountered with the two point detonation of a ring or cylindrical charge.

FIG. 7 is a schematic view similar to FIG. 6 but utilizing a plurality of explosive diodes to render a two point detonation feasible.

FIG. 8 is a schematic sectional view of a warhead according to the present invention showing the relationship between the detonation ring and the main explosive charge.

FIG. 9 is a fragmented detailed view of the end'plates shown in FIG. 8.

FIG. 10 (a-c) is a schematic view of a diode network for connecting the explosive elements of the warhead shown in FIG. 8.

FIG. 11 shows an electrical diode network corresponding to the explosive diode network of FIG. 10.

FIG. 12 is a schematic view showing the details of a linear diode.

FIG. 13 is a schematic cross-sectional view of an explosive diode network to accomplish line detonation of the explosive means shown in FIG. 10 utilizing linear diodes.

FIG. 14 is a partial view of an explosive logic element according to the present invention for controlling the commencement of detonation of a selected explosive segment in an explosive means.

FIGS. 15a and 15b are explanatory schematic views showing the operation of the explosive logic element in FIG. 14.

FIG. 16 is a schematic sectional view of a modification of the present invention providing for isotropic initiation in the event of fuse failure.

FIG. 17a is a schematic view of an initiation ring similar to FIG. 16 for an eight sector warhead.

FIGS. 17b and 17c are schematic views of modified isotropic initiation devices.

FIG. 18 is a schematic cross sectional view of a simple detonation delay for end initiated explosive segments arranged around a cylindrical case.

FIG. 19 is an elevation view, partly in section, of FIG. 18.

FIG. 20 is a schematic sectional view of a planar detonation control system for arbitrary surfaces.

FIG. 21 is a schematic flow diagram for the shock waves showing their path of travel in FIG. 20.

FIG. 22 is a schematic top plan view of the arrangement shown in FIGS. 20 and 21.

FIG. 23 is a sectional view of an hexagonal array of explosive elements utilizing the diode interconnection of FIG. 20.

FIG. 24 is a schematic view showing the diode interconnections of the explosive segments of FIG. 23.

FIG. 25 is a sectional schematic view similar to FIG. 20 showing the relationship of continuation segments to the dilation elements.

FIG. 26 is a cross sectional schematic view of a warhead utilizing the arrangement of FIG. 25 to provide explosive shaping of the case.

FIG. 27 is a schematic plan view of a warhead having a cylindrical charge filled with a fragmentation core.

FIG. 28 is a schematic view of an arrangement similar to FIG. 27 showing a detonation sequence to achieve directionality of the fragmentation core.

FIG. 29 is a cross sectional view taken generally along the line 29-29 in FIG. 28.

FIG. 30 is a schematic view showing the arrangement of pyrocore in each explosive segment.

FIG. 31 is a schematic sectional view showing a modified asymmetric timing arrangement similar to FIG. 19.

F lg. 32 is a schematic sectional view of an arrangement for sequencing explosive segments by means of metal shock prisms.

FIG. 33 shows a plurality of circular T-shaped linear AND gates shocked concentrically about an explosive core.

FIG. 34 is a schematic view of a typical line wave generator.

FIG. 35 shows a buffer device for eliminating collision fronts in the line wave generator of FIG. 34.

FIG. 36 is a cross sectional schematic view of a line detonating sheath showing a plurality of linear AND gates.

FIG. 37 is a schematic view of clustered AND gates, either linear or planar.

FIG. 38 is a modified schematic view of two sets of clustered, opposed linear or planar AND gates with a shaped-charge" bootleg.

FIG. 39 is a modification of the opposed linear or planar AND gates with controlled delays to permit the outer set to pass through the inner set.

DETAILED DESCRIPTION OF THE INVENTION Although the isotropic detonation of many warheads is acceptable and sometimes even desirable there are numerous times when it is desirable to concentrate the explosive kill mechanism in a specific lateral direction relative to the direction of travel of the warhead. Oftentimes a missile having a cylindrical warhead merely approaches the general vicinity of the target and is so set up that it will explode as the missile passes the target. In situations such as this, the entire kill shouldbe directed transversely to the axis of the cylindrical warhead in a direction toward the target. Such an objective is impossible if the cylindrical warhead is isotropically detonated thereby sending the fragments of the surrounding casing radially outwardly 360 about the axis of the cylindrical warhead. Such an arrangement is shown in FIG. 1 wherein a cylindrical warhead 10 is detonated in close proximity to a target 12. The arrows 14 show the pattern of the fragments and it is obvious that only those fragments of the warhead casing subtended by the angle a will effectively reach the target 12. Thus, the majority of the case fragments are directed away from the target in a case-around-charge design even with the best selection of initiation points.

With the inability of initiation techniques to improve the kill-mechanism efficiency, several variable geometry approaches have been tried in the past. These methods attempted to reorient the warhead components just prior to detonation. However, rapid deployment in a high speed air stream creates impossible aerodynamic problems while even the fastest mechanical movement has proven to be too slow for high speed intercept conditions.

In an effort to overcome these deficiencies, the arrangement shown in FIG. 2 was attempted wherein the cylindrical charge 16 surrounds a hollow casing or killmechanism 18. If the cylindrical charge is detonated along the line 20 in FIG. 2a which is on the opposite side of the casing 18 from the target, the liner or casing 18 is initially driven toward the target as shown by the sequence in FIGS. 2a-2c. However, simultaneously, the

- detonation is proceeding around the casing by a detonation rate of about 25,000 feet per second. This is generally many times faster than the fragment velocity so the detonation quickly surrounds the casing or core nullifying the initial impulse as was clearly shown in FIG. 2d. The only way the full benefits of this design can be obtained is for the inner shell or casing 18 to cross the warhead diameter before the arms of the detonation can meet as they travel in opposite directions around the cylindrical charge. If this can be accomplished the fragment velocity will be given an extra boost rather than being impeded.

In order to accomplish this the detonation is line initiated parallel to the cylinder axis as shown in FIG. 3a. By detonating the bifurcated charge 20 at a point spaced from and parallel to the hollow cylindrical charge two separate explosive waves will collide in the cylindrical charge thereby giving the linear an initially sharp peak. This is very desirable for both ease of crossing the void and the formation of a knife-like slug. The high C/ M (charge mass/ metal mass) would be primarily for high speed encounters or armor penetration. The

detonation and liner collapse will proceed as shown in the sequence of FIGS. 3a3d. As most clearly shown in FIG. 3d, the final explosive detonations of the cylindrical charge will meet after the liner has started to move outwardly through the charge so that the final explosive detonations will aid rather than oppose the liner ejection from the charge.

The velocity v of the liner can be approximated according to the following formula:

v k(D+d)/21r(l l-d) inches per in./,u.-sec. where k is the scale factor (how many diameters the liner travels), d is the inner'shell diameter, D is the outer shell diameter and 11' (D+d) u-sec. equals the time it will take detonation to travel halfway around the cylindrical charge to a point opposite the point of initiation. Thus, d= k/2 1r exp 6/12) feet/seconds.

v =k(4/3) X 10 exp 4 feet/sec.= 11,333 feet per second where k equals 1.

The required liner velocity of nearly 12,000 feet per second is quite high but should be achievable.

In a cylindrical warhead several techniques are available to help, such as having a high C/M and evacuating the core. By evacuating the core the energy transferred to the case is improved and pressure-volume working of air in the central void is eliminated. Line detonation also helps optimize the detonation head and sequenced initiation along the z-coordinate long axis of the cylinder will provide confinement on the z-axis by creating surfaces of shock collision, thereby utilizing the collision surfaces as artificial confinement.

As an alternative to imparting an extremely high speed to the liner as it is projected across the central void in order-to obtain directionality it is possible to obtain an equally effective design if the detonation simply takes longer to travel its path around the circumference of the cylindrical charge. It is not practical to lower the detonation velocity directly but the effective velocity can be lowered by increasing the path length. Such an arrangement is shown in a rather primitive form in FIG. 4a wherein a portion of the cylindrical charge 24 is shown arranged in a sinusoidal manner so that if detonation takes place at point 26 the explosion will have to travel a much longer path to reach a point diametrically opposite from point 26. A more refined version of the elongated path is shown in FIG. 4b wherein the explosive ring 28 has a plurality of notches 30 extending inwardly from the circumference and alternated with a plurality of indentations 32 extending outwardly into the ring. In FIG. 40 a variation of the construction shown in FIG. 4b is shown to obtain shock converging (or diverging if desired) in all sectors instead of alternating as shown in FIG. 4b.

The above principles of operation can also be applied to the construction of a detonation ring which in turn would initiate the explosion of another explosive charge in a warhead. An example of such an arrangement is shown in FIG. 5 wherein a thin ring 40 of high explosive material is detonated at point 42. The explosion travels in opposite directions around the ring 40 and meets at point 44 thereby causing a jet effect which will penetrate a buffer ring 46 and detonate the high explosive charge 48 located radially outwardly thereof.

In order'to vary the point on the ring where the detonation collision will take place, it is possible to detonate the ring at two spaced apart selected locations according to a predetermined timing sequence. As shown in FIG. 6 it is possible to obtain a detonation collision at any point along the short are of ring 50 between A and B by varying the timing of the detonation at each of these points. Unfortunately, there will also be an image point where a collision will occur. If the desired detonation is at point 52 then it is obvious that the detonation at point A has proceeded through an angle a and the detonation from point B has proceeded through an angle B. Meanwhile, the detonations have proceeded in the opposite directions from A and B through angles a and B, respectively and the collision image will occur at the midpoint of the remaining angle. Assuming a third detonation source or point C is added to the ring 50 and the three detonation points A, B and C are equally spaced about the ring it will be possible to sequence A and B to obtain collision on their short arc at a predetermined location. Once again an image point is formed but to produce the image point one of the A, B detonation arms must pass through point C.

By arranging the three points A, B and C as shown in FIG. 7 at equally spaced apart locations on the ring 54 v and inserting two blocking diodes 56 and 58 on either side of point C the suppression of the image point can be obtained. Since the detonation could occur at any two of three points, it is necessary to locate the diodes 60 and 62 on either side of point A and diodes 64 and 66 on either side of point B. The diodes may be constructed and arranged in accordance with the disclosure set forth in US. Pat. No. 3,430,564, granted Mar. 4, 1969. Assuming detonations occur at points A and B of FIG. 7 in the same sequence as described above with respect to FIG. 6 the explosions will meet at approximately point D. The explosions traveling along the segment 68 from point B toward point C will pass unimpeded through diode 64 but will be extinguished by diode 58 before it can meet with the explosion traveling along segment 70 from point A toward point C. Thus, the desired collision and subsequent jetting can be accomplished along any of the three arcs of the ring at a predetermined location by properly detonating any two out of the three detonation points in the proper se quence and the collision of the explosions will be prevented.

A practical arrangement for a detonation ring such as described in FIG. 7 is shown in FIG. 8 wherein a cylindrical warhead is provided with a thin outer case 72 and a cylindrical explosive charge and liner 74 interiorly thereof. A pair of explosive end plates 76 and 78 are provided and the detonation ring 80 or one of the other multiplexers detailed later is located within the hollow cylindrical explosive charge 74. Only two safe arming devices are necessary in the fuse 81 while still maintaining the ability to selectively detonate in any desired arming direction. The explosive end plate 78 may be separated into pie shaped wedges as shown in FIG. 9 so that the end plate detonation is synchronized with the detonation of the warhead segments.

Reverting to the cylindrical arrangement of the high explosive material such as shown in FIGS. 4a 4c in order to accomplish a longer effective detonation path, it is noted that it is also possible to provide a plurality of individual explosive segments connected together by an explosive diode network to provide the proper sequencing and timing. Such an arrangement is shown in FIG. 10a wherein the ring generally designated at 80 is divided into a plurality of explosive segments 82 and 84 separated and connected by means of a suitable diode network 86. FIG. 10b shows an enlarged detailed view of the diode network arranged between the two segments 82 and 84 and FIG. 10c shows a detailed exploded view of the diode network. The diode network is constructed from three buffer plates 88, 90 and 92 with the high explosive diode formed in cutout portions of the buffer plate 90. Each of the outermost plates 88, 92 of the sandwich arrangement are provided with cylindrical bores 94 filled with high explosive. These bores are aligned with the ends of the diodes 89 and 91 formed in the intermediate buffer plate 90. In operation, if the charge segment 84 is initiated first at the left hand end as viewed in FIG. 10b, the explosion will travel in the direction of the arrow until it reaches the explosive charge 94 intermediate the ends of the charge segment 84. The explosion will then travel through the diode in the direction shown by the arrows and initiate the explosion of the charge element 82 and so on around the cylindrical network. The electrical analog of the diode network is shown in FIG. 11.

The foregoing arrangement of the explosive segments connected by means of a diode network are suitable for end initiated explosions such as previously discussed above with respect to FIG. 8. However, the delayed path techniques may also be applied to a line initiated warhead and the proper operation for any aim point requires a network of the same type as that used for the end initiated warhead. In this case, however, a new logic device, the linear diode, is required to maintain line initiation. The linear diode is an extension of the explosive diodes disclosed in the classified successor to US. Pat. No. 3,430,564. Such a linear diode 100 is disclosed in FIG. 12 and is comprised of two planar sections disposed at right angles to each other with one planar section 102 having a thickness considerably less than the thickness of planar section 104. This arrangement utilizes the corner effect which is a phenomenon which takes place when a thin explosive layer is detonated along its surface. The thickness required is dependent upon the explosive used. For duPont EL 506-C sheet explosive this layer is about .025 inches. More sensitive compositions may require a thinner layer and less sensitive explosives require a thicker one. The thickness is generally called the critical thickness and is just sufficient to sustain a detonation. At these thickness levels the detonation can be inhibited easily especially by sharp changes of direction and the corner effect occurs when shock is forced around a sharp corner. Under these conditions, the shock must swing Wide around the corner leaving a sizeable half moon 106 of undetonated explosive. By making the channel into which the shock is trying to turn so narrow that its terminal end at the corner is entirely within the undetonated region the shock simply runs out of explosive and shuts itself off. Thus, the explosive cannot turn from a wide channel into a narrow one even though a shock coming from the'narrow channel into-the wide one has no difficulty negotiating the corner. Thus, we have an explosive diode with a continuous path of secondary explosive.

By utilizing the linear diodes described above the various segments of the warhead may be each connected together by a quartet of linear diodes in the manner shown in FIG. 13. The explosive segments 110 and 112 are separated by four buffer elements 114, 116, 118 and 120 arranged with respect to each other so as to provide wide channels 122, 124, 126 and 128 and narrow channels 130, 132, 134 and 136. Thus, an explosion initiating in segment will proceed through channels 122 and 134. Since the explosion proceeding through narrow channel 134 enters into wide channel 126 the explosion will be able to turn the corner and proceed through the central chamber 138 whereas the explosion proceeding through wide channel 122 is quenched since it cannot make the turn into narrow channel 130. Likewise, as the explosion proceeds through central chamber 138, the explosion entering passage 128 will be quenched since it cannot make the turn into narrow channel 136 whereas the explosion passing through narrow channel 132 can make the turn into wide channel 124 and thus initiate the explosion of segment 112. Thus, the line initiation of each segment is accomplished in the proper sequence and with the proper timing so as to effectively lengthen the path of travel of the explosion around the circumference of the warhead.

A linear AND gate is accomplished with the arrangement shown in FIGS. 14 and 15 by utilizing the flag or comer effect. An explosion or detonation started and traveling along the top arm 140 is maintained due to the sufiicient thickness of the top arm but the vertical arm 142 is too thin and the detonation is trying to die but is continually renewed by the progressing detonation of the top arm as shown by the wavefront 146. A plurality of horizontal output channels 148 and 150 are connected to the vertical arm 142 and if the shock is only traveling along the top arm and vertical segment the shock wave will be too weak to turn the corner from the vertical segment 142 into the horizontal segment 148 and 150 as best shown in FIG. 15b. However, if a detonation is progressing in the opposite direction on the bottom arm 152 a similar dying shock will be traveling along the narrower vertical arm 142. When the two dying shocks meet each other as shown in FIG. 15b, the two dying shocks are sufficient to give an output into the horizontal arm 148 or 150 depending upon the point where the detonation of the top arm 140 and the bottom arm 152 meet. Thus, by properly sequencing the detonations in the top and bottom arms a selected output segment may be intiated which in turn will initiate the proper segment of a cylindrical warhead to give the desired aimed detonation of the warhead.

Another form of demultiplexer ring for cylindrical warheads is shown in FIGS. 16 and 17. In FIG. 16 the fuses deliver pulses to the high explosive channel in timed sequence at points I and II so that the detonations proceed in opposite directions around the channel 160 and meet at point 162. When the detonations meet at point 162 the explosion will jet through the buffer 164 to initiate the cylindricalwarhead 166 at this point. Simultaneously, detonations proceed along channels 168 and 170 from points I and II into a delay 172 which is effectively longer than the channel 160. Thus, if either of the fuses should fail a detonation will travel through the delay 172 to initiate a central isotropic detonation of the warhead.

FIG. 17a shows the isotropic initiation of FIG. 16 arranged within a hollow cylindrical warhead having eight high explosive segments 174 separated by buffer strips 176. By choosing the proper time sequence of the fuses I and II the explosion is traveling in opposite directions along the channel 160 will meet adjacent a predetermined high explosive sector and jet through the buffer wall 164 to detonate the selected high explosive segment 174.

FIG. 17b shows a variation in the configuration of the high explosive channel 160 in FIGS. 16 and 17a. If one of the detonators should fail to initiate the explosion within the channel 160 at point A or point B the explosion from the other point will travel completely around the channel 160 and enter the heart shaped isotropic output channel 178. A similar isotropic output can be achieved from the T-shaped initiation ring shown in FIG. 17c which is similar to the ring shown and described with respect to FIGS. 14 and 15. Thus, if one of the detonators fail to initiate an explosion in either channel 140 or channel 152 there will not be explosions traveling in opposite directions to generate an output in the high explosive segments 150 shown in dotted lines. Thus, the single explosion will travel completely around the T-shaped ring and enter an isotropic output channel similar to that shown in FIG. 17b. Null gates turn-off isotropic leads at B, A when detonation results at A, B respectively, thus preventing isotropic interference with normal operation.

In FIG. 18 the high explosive segments 180 are arranged about a core (solid or hollow) 182 and are separated from each other by means of individual buffer strips 184. This is somewhat similar to the arrangement of high explosive segments shown in FIG. but instead of connecting the various segments by means of a diode arrangement, U-shaped lengths of MDF (mild detonating fuse) I86 extend between the segments 180 through the buffer walls 184. The initiation logic, complete with detonators, safe-arming and electrical terminals could be assembled on a plastic disc and secured directly to the top end of the warhead as viewed in FIG. 19. Thus, upon initiation of the explosion of one of the segments 180, the explosion would travel along the MDF 186 into the adjacent high explosive segments 180 on either side thereof to detonate the segments with the appropriate time delay. Thus, the explosion would travel from segment to segment in opposite directions to obtain the proper aiming of the explosive force and fragmentation pattern. The core 182 may be closed with end plates and evacuated as discussed previously or may be filled with a fragmentation core as discussed more in detail hereinafter. A typical construction technique might be to mold a plastic form into a metal case wherein both inside and outside shells of the case could be made in one piece to insure rigidity. After assembling the MDF or similar sheathed detonating cord, the main charge would be loaded. The plastic would serve as aform for the MDF, a mold for the main charge and a buffer. The metal shells would serve as both a kill-mechanism and the load bearing structure, The only critical part (the initiation logic) being contained on a sturdy plastic disc, the design would allow significant cost reductions in addition to sion is propagated from explosive segment to'explosive segment only in a predetermined direction.

FIG. 22 shows an arrangement of high explosive segments 198 having the MDF cord 200 arranged centrally of each sector with diode interconnections designated by the lines 202 extending therefrom to each of the four sectors located adjacent the four sides of the main sector respectively. Each of the branches 202 is formed with a diode similar to that described above at 196 so that the explosive force may travel only from a major section 198 to an adjacent sector and upwardly through the MDF cord 200 to initiate the adjacent sector 198. Utilizing the principal body of this arrangement the individual explosive segments 198 may take any suitable geometry such as the hexagonal array shown in FIGS. 23 and 24. The isochrone 204 in FIG. 23 is complete and concentric about the original point of destination 2% and the arrangement of the diode connections between the various hexagonal segments to achieve this isochrone is shown in FIG. 24. The isochrones have the same shape as the element in cross section but are rotated so that the locations of side and angle are interchanged. Although the elements can be of any size and shape, space-filling shapes of uniform size would be preferred in practical applications. Since the time dilation depends upon both element size and length, both of which are infinitely variable within limits, any reasonable dilation can be achieved. In practice, requirements vary from about 4:1 for light case warheads to about 8:1 for heavy cased charges. To minimize the parasitic loss due to buffering the element size (or grain) would be the largest consistent with required uniformity. Since regular hexagons are the most nearly circular of regular figures that fill the plane, the

markedly improving the performance over conventional warheads.

A variation of the detonation control shown in FIGS. 18 and 19 is achieved in FIG. 20 wherein the MDF or sheathed detonating cord 188 extends between the explosive segment l90and is formed into a diode 192 in the manner previously described. The diode 192 is formed with a wide leg I94 and a narrow leg 196 so that the explosion can only turn the corner in one direction. The net result of this arrangement is the explosion path pattern shown in FIG. 21 so that the exploelements would normally take that shape although other shapes might be chosen to fit external geometries, e.g. make the isochrones confront the case uniformly.

For a long charge, the element chosen for proper time dilation may not be more than a small fraction of the overall charge length. As shown in FIG. 25 continuation segments 208 of high explosive may be provided to accomplish this. Such continuation segments may be utilized to assist in forming the fragmentation dart as shown in FIG. 6 wherein the casing 210 is disposed adjacent the end of a plurality of continuation segments 212 which in turn are aligned with the individual elements of an array 214 of dilation elements similar to that shown in FIG. 23. In this way the shock waves designated by the lines 216 will reach the fragmentation plate at a predetemiined time sequence to achieve the fragmentation form shown in dotted lines at 218.

As mentioned before, the aimed warhead is first optimized in its gross geometry. The inside-out or chargearound-case design is considered optimum if all-way aiming is desired. The two main variants are the hollow and solid designs with the hollow design being discussed previously with respect to FIG. 3. Such a design delivers a very narrow, dense fragment beam, similar to a focused or shaped charge. The solid or fragment core variation offers advantages if a more dispersed but still aimed warhead is desired. The primitive fragment core has been previously proposed but without control proved to be ineffective.

Considering the basic fragment-core design in FIG. 27, it is noted that the core 219 is formed from a plurality of segments which completely fill the internal portion of the casing about which the high explosive charge 220 is disposed. Assuming the charge is detonated at 222, the aim direction will then be along the arrow 224 on the opposite side of the charge. The core, although initially driven in the end direction upon detonation of the high explosive, subsequently experiences an almost equal impulse in the opposite direction because the detonation velocity is about five times that of the core. Therefore, the explosion travels completely around the high explosive ring before the fragmentation core can be expelled from the warhead. By applying the digital techniques described above to the fragment core design, it is possible to effectively delay the detonation velocity but in so doing the explosive sector directly between the core and the target must be sacrificed. Although the smallest possible sacrifice is the sector just equal to the size of the core and located between the lines 226 and 228, a somewhat larger sector approximately equal to 20 percent of the charge mass and located between the lines 230 and 232 is more realistic to allow for core expansion or dispersion. This sacrificial sector is functionally a part of the core so in effect it adds to the metal mass M while subtracting from the charge mass C.

In applying the digital technique to the warhead of FIG. 27, the explosive ring may be divided into three concentric rings 234, 236 and 238 (FIG. 28). The inner annulus 238 is divided into eight reasonably chunky pairs of cells. Eight-way symmetry is desirable for an eight-way aiming design. The second annulus is divided into twenty chunky cells, or 10 pairs. The outer annulus 234 is divided into 24 cells. Each cell is buffered from its neighbors and will be connected to diodes as necessary. The numbers of annuli and divisions thereof are somewhat arbitrary. The depth of each annulus will be varied to adjust the time delay required. Since it is desired that the cells adjacent to the sacrificial section be detonated just as the core leaves the warhead, detonation will be symmetric about the aim line and started on the side opposite the target. It is de sirable for the outer annulus to lead the inner ones, both to shape the fragment spray and to provide an imploding effect. In FIG. 28, the various isochrone lines are shown at 240 and the sequence of detonation as indicated by the numbers which represent time units achieves the desired result. Detonation is started on both sides of the aim line in the middle annulus at and both the middle and inner annuli can conveniently have delays at two units/cell. The outer annulus, with more cells to accomplish, is given delays of one unit/cell. Thus, after about twelve detonation units, the warhead has completed its functioning. Now during this time the core should travel a sufficient distance to put the core center near the warhead rim, leaving it partly still in contact with the propelling charge.

If the core velocity is, for example, 8,000 feet per second, this means that:

12 time units R(feet)/8,000 feet/sec.

foot/8,000/feet/sec. l/l6,000 secs. Thus: I time unit l/l92,000 secs. .0052 X exp (3) sec. or 1 time unit 5.2 microseconds. This is well within the delay capability of the digital method, yielding a cell height of about one-half inch for the outer annulus and about 1 inch for the inner annuli.

FIG. 29 is a cross section through FIG. 28 showing the relationship of the time dilation elements and the extensions which surround the core 218.

The warhead designer, plagued by a highly inefficient system from the beginning (less than 1% of the possible chemical energy of the warhead mass is normally delivered to the target) is loath to tolerate a 20% sacrificial loss in the fragment-core design. A method of partially recouping this loss, potentially applicable to many explosive systems will now be described with reference to FIG. 30. Although detonation of the sacrificial sector in the warhead cannot be permitted, the sector can be detonated after ejection or forced to deflagrate. Ejection of the core is accomplished in about -microseconds so after several hundred microseconds the ejected material cannot appreciably influence the core fragmentation whether it detonates or not. Indeed deflagration to detonation transition about 10 milliseconds after ejection would locate the ejecta near the target with most desirable results.

The ejecta is already segmented into chunks by the digital requirement and these may be expected to at least partially survive ejection forces. Minimal modification to the buffering strength as well as segmenting the continuation segments (that is making them more chunky by adding buffer layers with detonation passthrough areas) would suffice to make the explosive ejecta a useful part of the kill-mechanism if a practical means of inducing non-detonating decomposition can be found. Pyrocore (or a similar fabrication) is precisely appropriate for the accomplishment of this task. By threading pyrocore 239 through the sectors 237 (or in the buffer layer 241), decomposition, at the speed of detonation, but without detonation itself, may be induced. Such an arrangement of pyrocore in the various sectors is shown in FIG. 30.

FIG. 31 shows a method of increasing the dispersion if over aiming occurs by use of in-line diodes 240 between the legs of the U-shaped MDF connectors to make the path length longer in one direction than the other. The assymetry thus induced results in multiple linercollisions and increased scatter.

A delay technique slightly different and possibly more compact than that detailed in FIG. 20 would make use of the interaction between explosive and metal or other type shock conductors. Explosive slabs 242 are alternated with layers of buffer material 244. Metal caps 246 form shock prisms alternating top and bottom to form a meandering path. The straight through paths would allow thinner explosive layers and the strength of the shock reentering the explosive from the metal prisms can be focused for local enhancement.

Turning now to an improved method of line initiation of a cylindrical warhead, an eight-way aiming device will be assumed although the constructions, as are the ring and detonation control methods, are equally applicable to any number of aiming directions. The conventional solution would merely feed the eight outputs from the T-ring of FIGS. 14 and 15, via detonating cord, to eight separate line wave generators. Although feasible, this approach is highly inefficient, since eight explosive layers with sufficient buffering to isolate each would be required. Such parasitic loss might well ne- The desirability of this would depend largely upon the kill-mechanism.

A second alternative, somewhat more complicated, can provide either multi-point or continuous line initiation. A typical line wave generator 260 (FIG. 34) consists of a triangular piece of explosive sheet with numerous holes 262 disposed therethrough. The holes are equally spaced in rows parallel to the sides of the device so that when the generator is detonated at the vertex 264 the shock front must travel a meandering path through the gate" between the holes. The shock front is thus broken into numerous small fronts which arrive at the base of the triangle with an essentially flat although somewhat-bumpy profile, roughly illustrated by the shock wave line 266.

Instead of a triangular shape, a cylindrical shape which just fits over the periphery of a cylindrical warhead may be utilized. Holes may be cut in the sheet with the holes arranged in vertical and horizontal rows with alternated rows staggered. If this cylinder is detonated at one point half way between the ends of the cylinder the shock will proceed in both directions around the warhead and collide along a vertical line on thecylindrical element directly opposite the starting point. The shock collision can be used in standard ways to propagate into the warhead either by jutting through a buffer or by using linear AND gates at the aim points. The line wave cylinder is constructed of explosive sheet at the critical thickness when linear gates are used. Lin-,

ear gates offer the obvious advantages of reliability over the jet-through method.

The reliability of the gate method can be negated in practice since the detonation collision must occur at the gate junction .with the cylinder. This is best illustrated in FIG. 36 wherein a plurality of gates 270 are disposed through the buffer ring 272 so that the shock waves traveling about the explosive ring 274 from the detonation point 276 will meet at278 and pass through the gate 270 into the high explosive charge 280. In the case of certain sheet explosives the size of this target is only about .025 inches.

It would not be possible to merely widen the gates 270 to increase the chance of the short waves meeting at agate since the width of each gate must be limited Y to prevent the explosion from tuming the corner into.

the first gate the shock wave reaches.

By stacking a series of junctions or gates 282 as shown in FIG. 37, each separated by a thin buffer 284, numerous targets can be provided. Collision of the shock fronts at any one of these gates 282 will propagate the explosion to the appropriate sector radially inwardly.

Unfortunately, the collision has an equal chance of occurring at one of the buffer regions 284 and to eliminate failure when this occurs it is possible to arrange an identical stack of junctions 286 on the opposite side of the explosive sheet cylinder 288. In this modification shown in FIG. 38, the explosive fingers or pass-through areas 286 are opposite the buffer regions 284 in the original stack. Thus, no matter where the collision occurs, one of the fingers is properly positioned to detonate. If the explosion passes through the fingers 286 and explosive path may be provided at 290 to a linear shaped charge 292 which will shoot through the buffer material 294 and 296 into the aim sector. The shaped charge can be made as large as necessary since only one is required in each of the sectors to be fired.

Still another method of widening the target region for linear gates is shown in FIG. 39 wherein the explosive sheet 300 is divided into two explosive paths 302 and 304 with the path 304 nearest the output having delays D and D on either side of a set of finger gates 306 similar to the paths 282 and 286 described above. Assuming the buffers 308 are of equal width as the diode output and the delays D, D are not quite equal, the shock collision will occur along the outer path 302 away from the output well before the shocks collide along the inner path 304. Another set of diode fingers 310 are located along the inner path with buffer strips 312. The inner and outer fingers are aligned so that if the explosions traveling along the outer path meet adjacent an outer finger 306 the explosion will cut across the inner path 304 and through the inner finger aligned with the outer finger. Thus, a set of destructive cross overs are located along the inner path. However, if the collision takes place adjacent a buffer strip 308 along the outer path 302, the shocks on the inner path will continue and collide at an explosive region with a resultant output.

1 Such an arrangement of cluster fingers (FIG. 39) may be used in FIG. 17a to transmit the explosion through the buffer element 164 into the explosive segments 174. Once an initial segment 174 is detonated the time sequencing of the detonation of the remaining segments will be accomplished in accordance with any of the means previously described above.

What is claimed is:

1. An explosive device comprising primary explosive charge means divided into a plurality of segments, first explosive logic means interconnecting said segments in a manner which will determine the direction and lengthen the path and travel time of the explosion through all of said segments in sequence subsequent to the detonation of at least one of said segments and second explosive logic means for determining which of said segments will be detonated first, said first and second explosive logic means thereby controlling the order and time sequencing of the detonation of said segments.

2. An explosive device as set forth in claim 1 further comprising bufi'er means, substantially isolating said segments from each other.

3. An explosive device as set forth in claim 1, further comprising a hollow cylindrical case, a plurality of said segments being disposed about said case to form a hollow explosive cylinder and said second explosive logic means being comprised of an explosive ring coaxially disposed in contiguous relationship with said explosive cylinder.

4. An explosive device as set forth in claim 3 wherein said explosive ring is provided with three equally spaced input points adapted to be connected to a fuse assembly, a pair of opposed explosive diodes integrally formed in said explosive rings on opposite sides of each of said input points whereby upon detonation of two selected points in proper timed sequence, a selected explosive segment will be detonated.

5. An explosive device as set forth in claim 3 wherein said explosive ring is comprised of a U-shaped explosive charge having radially directed leg portions substantially thicker than the bight portion and having oppositely directed radial explosive fingers connected to the middle of said bight portion, whereby upon timed detonation of each leg at two spaced preselected points the oppositely travelling explosions will meet to detonate a selected finger.

6. An explosive device as set forth in claim 5 wherein each of said fingers is disposed contiguous to a segment of said explosive cylinder so that upon initiation of an explosion in one of said fingers, the explosive segment contiguous thereto will be detonated.

7. An explosive device as set forth in claim 5, wherein a plurality of said rings are concentrically disposed about said explosive cylinder to provide multi-point ini tiation of said explosive segments.

8. An explosive device as set forth in claim 4, wherein said explosive ring is discontinuous and is provided with an initiation point at each end closely adjacent each other and adapted to be connected to the fuse assembly and further comprising explosive delay means connected to each of said points and having an effective length longer than the circumference of said ring to provide an isotopic initiation of the explosive device if one of said two point should fail to initiate.

9. An explosive device as set forth in claim 3, wherein two closely adjacent initiation points are located on said ring for connection to the fuse assembly and further comprising explosive leads connected to said ring adjacent each of said points at an angle to prevent detonation thereof upon detonation of the point closest thereto, said explosive leads providing isotopic detonation of said explosive device on failure of one of said points to initiate.

10. An explosive device as set forth in claim 3 further comprising a buffer ring concentrically arranged with respect to said explosive ring and having a plurality of explosive fingers extending radially therethrough, said fingers each being contiguous to a selected explosive segment whereby upon detonation of said ring at a point substantially diametrically opposite a selected finger, the explosions travelling in opposite directions about said ring will meet adjacent said finger to detonate said finger and the explosive segment contiguous thereto.

11. An explosive device as set forth in claim wherein each finger is provided with a plurality of spaced-apart buffer elements adjacent said ring to pro vide a plurality of connecting points.

12. An explosive device as set forth in claim 11 further comprising an explosive charge located on the opposite side of said ring from each of said fingers and having a plurality of additional buffer elements arranged in staggered relationship with respect to said first mentioned buffer element, shaped charge means in said explosive charge aligned with said finger to provide an alternate explosive path to said finger if said explosions meet adjacent one of said first mentioned buffer elements.

13. An explosive device as set forth in claim 11 further comprising additional buffer elements disposed on the opposite side of said first mentioned buffer elements from said explosive ring, explosive delay means located in said explosive finger adjacent each end of the first mentioned buffers to delay the initiation of the explosive intermediate said first mentioned buffers and said additional buffers whereby if the explosions in said ring meet adjacent a buffer element the explosions travelling through said delays will meet at a point intermediate two of said additional buffer elements to provide detonation of the contiguousexplosive segment.

14. An explosive device as set forth in claim 2 wherein said first explosive logic means comprises a U- shaped length of detonating fuse extending through said buffer means to connect each explosive segment with each contiguous explosive segment to provide a time delay between the detonation of successive explosive segments.

15. An explosive device as set forth in claim 14 wherein one leg of said U-shaped explosive fuse is substantially thinner than the bight portion to define an explosive diode.

16. An explosive device as set forth in claim 15 wherein said explosive segments are disposed in an array having U-shaped explosive diodes interconnecting each segment to each contiguous segment said diodes being arranged to provide concentric isochrones about the initial point of detonation in said array.

17. An explosive device as set forth in claim 15 wherein said segments are dispersed in a plurality of concentric rings about a central case and arranged to define oppositely travelling explosive wave fronts of a predetermined character in dependence upon the detonation sequence of said rings along a common radial line.

18. An explosive device as set forth in claim 17 wherein said segments are extended to define an explosive cylinder and said case is comprised of a plurality of individual contiguous fragmentation segments.

19. An explosive device as set forth in claim 18 wherein deflagratable elements are embedded in said explosive segments whereby those segments not detonated prior to the ejection of the case will be detonated upon exposure of said elements.

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U.S. Classification102/305, 102/701
International ClassificationF42C19/095, F42D1/04, F42B1/00
Cooperative ClassificationF42B1/00, F42C19/095, Y10S102/701, F42D1/04
European ClassificationF42C19/095, F42B1/00, F42D1/04