The subject matter disclosed herein generally relates to explosive cutters and, more particularly, to charge holders for linear shaped charge explosive cutters.
Explosive cutters, such as linear shaped charge devices, typically are mounted in a charge holder to secure the explosive cutter to a structure (e.g., an aircraft canopy, a wall, a door, etc.). The charge holder may be arranged or designed to mitigate the effects of back blast in order to prevent explosive concussion and/or material to be ejected in a direction away from an intended direction (e.g., away from a cutting direction). Charge holders are typically formed from a single material, such as a closed cell foam, rubber, or metal structure.
According to some embodiments, charge holders are provided. The charge holders include a first portion formed of a first material, the first portion having a longitudinally discontinuous internal feature integrally formed therein and a second portion formed of a second material, the second portion extending from the first portion and defining a charge support channel. The longitudinally discontinuous internal feature is formed from at least one third material, wherein at least one the third material is different from the first material.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the first and second portions are integrally formed.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the longitudinally discontinuous internal feature comprises a plurality of fiber structures, void structures, or lattice structures discontinuously distributed along a longitudinal axis of the first portion.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the longitudinally discontinuous internal feature comprises a combination of at least two of fiber structures, void structures, and lattice structures discontinuously distributed along a longitudinal axis of the first portion.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the second portion includes a floor shaped to receive a charge and sidewalls, wherein the floor and sidewalls define the charge support channel.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the longitudinally discontinuous internal feature comprises a plurality of subfeatures discontinuously distributed along a longitudinal axis of the first portion, wherein locations between the discontinuously distributed subfeatures of the first portion are solid.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include a charge located within the charge support channel.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include at least one initiator attached to at least one of the first portion and the second portion and operably connected to the charge to initiate an explosion of the charge.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include one or more external features formed on the first portion, wherein the one or more external features are arranged to receive an attachment mechanism to attach the charge holder to a structure to be cut.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the structure to be cut is a portion of an aircraft, a portion of a launch vehicle, a portion of a door, or a portion of a wall.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the second portion is arranged to direct a blast of a charge out of the charge support channel and away from the first portion.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the at least one third material is at least one of a liquid, a solid, and a gas.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the first material and the second material are the same material.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the charge holders may include that the longitudinally discontinuous internal feature comprises at least one of fibers, granules, powder, fluids, gels, wires, lattice structures, fiber structures, granules of material, powder materials, cavities, voids, gaps, and void patterns.
According to some embodiments, methods for manufacturing charge holders are provided. The methods include forming a first portion using a first material, integrally forming a longitudinally discontinuous internal feature within the first portion, and forming a second portion using a second material, the second portion formed to extend from the first portion and define a charge support channel. The longitudinally discontinuous internal feature is formed from at least one third material, wherein at least one the third material is different from the first material.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the methods may include that the first and second portions are integrally formed.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the methods may include that the longitudinally discontinuous internal feature comprises a plurality of fiber structures, void structures, and/or lattice structures discontinuously distributed along a longitudinal axis of the first portion.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the methods may include that the first portion, the second portion, and the longitudinally discontinuous internal feature are additively manufactured as a unitary body.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the methods may include forming one or more external features on the first portion, wherein the one or more external features are arranged to receive an attachment mechanism to attach the charge holder to a structure to be cut.
In addition to one or more of the features described herein, or as an alternative, further embodiments of the methods may include that the first portion and the at least one internal feature are formed substantially simultaneously.
The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, that the following description and drawings are intended to be illustrative and explanatory in nature and non-limiting.
The subject matter is particularly pointed out and distinctly claimed at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
As shown and described herein, various features of the disclosure will be presented. Various embodiments may have the same or similar features and thus the same or similar features may be labeled with the same reference numeral, but preceded by a different first number indicating the figure to which the feature is shown. Although similar reference numbers may be used in a generic sense, various embodiments will be described and various features may include changes, alterations, modifications, etc. as will be appreciated by those of skill in the art, whether explicitly described or otherwise would be appreciated by those of skill in the art.
Referring to
The severable portion 102 is separable from the structure 100 by activation of an explosive cutter 106, as will be appreciated by those of skill in the art. The explosive cutter 106 is attached to the structure 100 along a cutting line 108 that defines the periphery of the severable portion 102 (when the severable portion 102 is attached to or part of the structure 100). The explosive cutter 106 may be a linear charge explosive that is housed within a charge holder, as described herein. When the explosive cutter 106 is activated, the severable portion 102 is separated or ejected from the structure 100 and an opening 110 is formed in the structure 100, as shown.
Turning now to
The explosive material 218 has a “V-shaped” profile and can be formed with a desired length. The charge 212 can include a tamp 220 or other confining structure, as will be appreciated by those of skill in the art, that surrounds the explosive material 218. The tamp 220 can be provided to aid in directing the explosion of the explosive material 218. A liner 222 can be provided on a side of the explosive material 218 in the cutting direction 216. Upon detonation of the explosive material 218, the shape of the charge 212 along with the tamp 220 focuses an explosive high pressure wave toward the target 214. In some embodiments, as the explosive high pressure wave becomes incident to the tamp 220, the liner 222 of the charge 212 will collapse, thus creating a cutting force directed at the target 214. The detonation projects in the cutting direction to form a continuous, knife-like (planar) jet. The jet cuts any material in its path (e.g., the target 214), to a depth depending on the size and materials used in the charge (e.g., the choice of explosive material 218). In some embodiments, a liner or other material or object can be positioned in the base of the “V-shape” which, upon detonation, becomes a projectile that performs the cutting action (e.g., is projected in the cutting direction 216 to cut the target 214).
Explosive cutters, such as charge 212 shown in
Embodiments described herein are directed to charge holders that provide improved back blast mitigation. Various embodiments of the present disclosure are directed to additively manufactured charge holders such that the mechanical properties and mass distribution throughout the charge holder are selectively controlled to optimize performance while mitigating or preventing back blast. Embodiments described herein enable management of debris (size and velocity of particles produced upon detonation) and resistance to induced mechanical environments. By controlling various manufacturing and design characteristics (e.g., shape, density of charge holder materials, location/thickness of continuous fibers, mechanical properties, mass distribution, etc.) of the charge holder, the charge holder can be designed to specific or predetermined back blast mitigation capabilities (e.g., debris size, speed, and direction of flight).
Embodiments of the present disclosure can take various shapes, geometries, and/or be formed from various different materials. For example, in some embodiments, the charge holders of the present disclosure can be formed from composite materials. For example, one non-limiting example of a charge holder of the present disclosure is a nylon material with graphite fibers embedded therein. Further, in some embodiments, internal features can be formed to provide additional back blast mitigation characteristics. For example, in a non-limiting example, a honeycomb printed structure can be formed within an interior of the charge holder. Additionally, in some embodiments, additional support, structure, and/or material can be embedded within the charge holder. For example, the addition of a para-aramid synthetic fiber structure (e.g., Kevlar®) and/or strands printed within a graphite fiber/nylon material can provided additional back blast mitigation. As will be appreciated by those of skill in the art, the size, orientation, structure, shape, etc. of internal features and/or characteristics and/or the amount/location of internal embedded materials can be designed to achieve desired back blast mitigation while also being catered to a specific application.
Turning to now to
As shown, the charge holder 324 is formed with internal features. For example, as schematically shown in
As described above, the first and second portions can be formed from the same or different materials. The internal features can be positive structures or negative structures within the first portion 326 and, in some embodiments, can extend into the second portion 328, as illustratively shown in
In some embodiments, it may be advantageous to deposit or form granules within the cavities 336. In some such embodiments, deposition or formation of granules can be achieved through selective laser sintering and/or selective laser melting additive manufacturing processes. The processes can form one or more layers of powder in the form of granules. In such formation, laser light is used to sinter or melt the powder in selected areas to form a desired net shape of the final product. Each subsequent layer of powder is laid down and heated with the laser to build the complete shape. The final shape may fully entrap powder if all material surrounding it has be sintered/melted. Such trapped granules or powder within the structure can provide additional benefits including, but not limited to, improvement in resistance to vibration.
In some embodiments, the third material may be the same as the second material. In accordance with embodiments of the present disclosure, the third material can be a solid, a liquid, or a gas. That is, even when the internal features are voids or cavities, the voids or cavities comprise a third material (e.g., in the form of a gas). Thus, the term “third material” is not to be limiting to solids, but rather includes any phase state of one or more materials that form or fill the internal features of the charge holders of the present disclosure.
The charge support channel 330 of the second portion 328 can be sized and shaped to accommodate the charge 312 and also aid in directly and/or controlling an explosive jet that is generated by the charge 312 to perform a cutting action. For example, the second portion 328 may have a predetermined shape and size to offset the charge 312 from a target (e.g., a surface of a structure to be cut). As shown, the second portion 328 includes a floor 338 and sidewalls 340. The floor 338 is shaped to receive the charge 312, and in the present illustration is chevron or V-shaped to accommodate the like-shaped charge 312. The sidewalls 340 extend away from the floor 338 (in a direction away from the first portion 326) and the floor 338 and the sidewalls 340 define the charge support channel 330. As will be appreciated by those of skill in the art, the sidewalls 340 can provide an offset of the charge 312 from a target (e.g., surface of a structure to be cut) by a predetermined distance that allows the charge 312 to generate an explosive blast of sufficient strength to cut the target.
Turning to
As shown and describe above, the charge holders are shown having internal features such as fiber structures 332, void structures 334, and/or lattice structures 442. Various combinations thereof can be employed to achieve a desired result, such as improved back blast mitigation. As used herein, the various structures shown and described above may be referred to herein as “internal feature(s).”
In addition to being formed with internal features as shown and described above, charge holders as described herein may be formed in any geometric shape or size to accommodate installation to a structure to be cut. For example, turning to
Turning now to
At block 702, a first portion of a charge holder is formed. The first portion may be formed with one or more external features at one or more locations, with the external features designed for attachment and/or other purposes (e.g., attachment to a structure to be cut, connection to one or more initiators, etc.).
At block 704, one or more internal features are formed within the first portion. The internal features can be positive structures or negative structures. Positive structures within the first portion can include wires, lattice structures, fiber structures, granules of material, etc. Negative structures are shapes or structures that are defined by the material of the first portion and can include, without limitation, cavities, voids, gaps, a void pattern, etc. within the material of the first portion. The internal features, when positive, may be formed from materials that are different from the material used to form the first portion and/or material having different material properties from the material of the first portion (e.g., density, tensile/compressive strength, brittleness, etc.).
At block 706, a second portion is formed. The second portion is formed integrally or continuously with the first portion. The second portion is formed to define a charge support channel. The charge support channel is formed geometrically and/or sized to receive a charge, such as a linear shaped charge. The second portion can be formed using the same material as the first portion (a first material) or may be different from the first portion (a second material), with the internal features being another material (a third material). In some embodiments, two or more of the first, second, and third materials may be the same material.
The flow process 700 can employ various materials for forming the charge holder and/or parts thereof. For example, the first portion and second portion can be formed using respective first material(s) and second material(s) and the internal features are formed using a respective third material(s). In some embodiments, the first and second materials are the same material. Further, in some embodiments, different internal features are formed of different third materials. In one non-limiting example, the first and second portions are composed of nylon filled with carbon fibers and the internal features are composed of para-aramid synthetic fibers. The materials may be selected to provide efficient cutting to be achieved by a charge within the charge holder while also minimizing, mitigating, and/or eliminating back blast in a direction away from the cutting direction.
As noted, the flow process 700 is an example manufacturing process for forming a charge holder in accordance with the present disclosure. Although shown in a flow-process (e.g., an order), those of skill in the art will appreciate that the various steps may be performed simultaneously, substantially simultaneously, or in discrete, separate manufacturing steps. In some embodiments, two of the steps may be performed simultaneously or substantially simultaneously, and the third step may be performed separately. Thus, there is no intended limitation on the flow process 700 to be imparted by the illustrative flow. In one non-limiting example, “substantially simultaneous” means that two steps happen concurrently, e.g., in a printing process where one material is printed for the first portion and a second material is printed for the second portion.
Turning now to
As shown in
Although shown in
The term “discontinuous” as provided here, as it relates to the subfeatures, means that the subfeatures do not extend an entire longitudinal length of the charge holder. That being said, in some embodiments, a combination of discontinuous subfeatures and continuous internal features can be employed without departing from the scope of the present disclosure. For example, referring to
Advantageously, embodiments described herein provide charge holders that leverage additive manufacturing technique to selectively control mechanical properties and mass distribution throughout the charge holder to optimize performance. Example, performance variables include management of debris (size and velocity of particles produced upon detonation) and resistance to induced mechanical environments. By printing a shape, the density of the material, location/thickness of continuous fibers, mechanical properties and mass distribution of the charge holder can be designed to specific debris mitigation requirements (debris size, speed and direction of flight).
The use of the terms “a”, “an”, “the”, and similar references in the context of description (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or specifically contradicted by context. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., it includes the degree of error associated with measurement of the particular quantity). All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.
While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions, combinations, sub-combinations, or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments.
Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.