Patent Publication Number: US-2019168899-A1

Title: Separation device assemblies

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from U.S. Provisional Patent Application Ser. No. 62/593,367, filed Dec. 1, 2017. The contents of the priority application are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     The subject matter disclosed herein generally relates to separation device assemblies and, more particularly, to modular frangible joint separation device assemblies. 
     Linear explosive frangible joints are used to explosively separate two components, such as that of a launch vehicle, satellite, or other type of space or air travel vehicle during flight or operation (e.g., to separate two vehicle stages or to separate a payload from a launch vehicle). For example, it is known to utilize a single, elongated, flexible continuous explosive cord that comprises, e.g., a mild detonating fuse (“MDF”) that explodes upon detonation. The explosive cord may be encased in a silicone rubber or other pliable material that is surrounded by a stainless steel tube. This arrangement may be applied to a portion or all of the periphery or circumference of a joint, connection point or location between two components that are desired to be explosively separated at that location at a predetermined time. The explosive cord is typically initiated at one or more ends of the cord and the cord causing the cord to explosively detonate along its length to separate the components. 
     However, due to the nature of the structural components that are joined (and then separated) by the frangible joints, each application is unique. For example, the frangible joints may include one or more flanges or other structures that are arranged to specifically attach to a portion of the structural component. Each application is different and thus each application may require a different arrangement of flanges or other attachment mechanisms. Accordingly, it may be desirable to improve frangible joints to be more versatile in application. 
     SUMMARY 
     According to some embodiments, separation device assemblies are provided. The assemblies include a first plate having a first end member, a second end member, and a separation wall extending between the first end member and the second end member, the first end member and the second end member each defining a respective contact surface and a respective engagement surface, a second plate having a first end member, a second end member, and a separation wall extending between the first end member and the second end member, the first end member and the second end member each defining a respective contact surface and a respective engagement surface, and a fracture groove located on each of the separation walls proximate a respective first end member. The first end member, the second end member, and the separation wall of the first plate define a first plate expansion device channel and the first end member, the second end member, and the separation wall of the second plate define a second plate expansion device channel, When the respective contact surfaces of the first and second end members of the first plate contact the respective contact surfaces of the first and second end members of the second plate, the expansion device channels of the first and second plates form an expansion device cavity. When the respective contact surfaces of the first and second end members of the first and second plates are joined, the first and second plates form a frangible joint. The respective engagement surfaces are configured to engagement with receiving channels of attachable mounting devices. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include an expansion device located within the expansion device cavity. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include a retaining member located within the expansion device cavity and arranged to retain the expansion device to a portion of the first and second plates. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include a positioning member located within the expansion device cavity configured to position the expansion device within the expansion device cavity. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the positioning member is integrally formed with at least one of the first plate and the second plate. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include at least one fastener fixedly attaching the first plate to the second plate. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the first plate is welded to the second plate. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include a first attachable mounting device attached to the frangible joint at the first end members of the joined first and second plates. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include a second attachable mounting device attached to the frangible joint at the second end members of the joined first and second plates. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the first attachable mounting device defines a receiving channel arranged to engage with the engagement surfaces of the first end members. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the first attachable mounting device comprises an attachment element and a frame. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the frame comprises a first arm, a second arm, and a channel floor, wherein the first arm, the second arm, and the channel floor define a receiving channel for engaging with a portion of the frangible joint. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the attachment element is configured to attach to a structural component. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the structural component is a portion of a launch vehicle. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the attachment element has one of a clevis arrangement, an “L” flange arrangement, or a stock-straight arrangement. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the first attachable mounting device includes a positioning member recess for receiving at least one of a positioning member and a retaining member. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the first attachable mounting device includes a fastener aperture for receiving a fastener, the fastener fixedly retaining the first end members of the joined first and second plates to the first attachable mounting device. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include that the first attachable mounting device is welded to the first end members of the joined first and second plates. 
     In addition to one or more of the features described herein, or as an alternative, further embodiments of the separation device assemblies may include a plurality of frangible joints. 
     According to some embodiments, separation device assemblies and components thereof as shown and described herein are provided. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is a perspective view of a segmented separation structure in accordance with one embodiment of the present disclosure; 
         FIG. 2A  is a partially cross-sectional view of an example prior art separation device assembly; 
         FIG. 2B  is a view similar to that of  FIG. 2A  of the prior art separation device assembly after detonation; 
         FIG. 3A  is a schematic cross-sectional illustration of a portion of a separation device assembly in accordance with an embodiment of the present disclosure; 
         FIG. 3B  is a schematic illustration of an unassembled, isometric view of the separation device assembly shown in  FIG. 3A ; 
         FIG. 4A  is a schematic cross-sectional illustration of an attachable mounting device in accordance with the present disclosure; 
         FIG. 4B  is an isometric illustration of the attachable mounting device of  FIG. 4A ; 
         FIG. 5A  is a plan view schematic illustration of a plate of a frangible joint in accordance with an embodiment of the present disclosure; 
         FIG. 5B  is a schematic isometric illustration of the plate of  FIG. 5A , with various components of a frangible joint installed therein; 
         FIG. 5C  is a cross-sectional schematic illustration of the plate of  FIG. 5A ; 
         FIG. 6  is a schematic illustration of a separation device assembly in accordance with an embodiment of the present disclosure; and 
         FIG. 7A  is a schematic illustration of a configuration of a separation device assembly in accordance with the present disclosure; 
         FIG. 7B  is a schematic illustration of a configuration of a separation device assembly in accordance with the present disclosure; 
         FIG. 7C  is a schematic illustration of a configuration of a separation device assembly in accordance with the present disclosure; and 
         FIG. 7D  is a schematic illustration of a configuration of a separation device assembly in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
       FIG. 1  schematically illustrates a segmented separation structure  101 , such as a frangible joint. The segmented separation structure  101 , having a plurality of segments  103 . The segments  103  are jointed or attached at seams  105 , with connections achieved as will be appreciated by those of skill in the art. An expansion device  107  is positioned within the segments  103 . The ends of the expansion device  107  are connected to a detonation manifold  109  that is in signal transfer communication with one or more of signal transfer lines  111  in a manner well known to those skilled in the art. 
     The signal transfer lines  111  are used to communicate an activation signal to the detonation manifold  109 . Activation of the detonation manifold  109  triggers expansion of the expansion device  107  within the segments  103 . As the expansion device  107  expands, the segments  103  will separate or split apart such that two ends of the segments will separate from each other. In one example, the segmented separation structure  101  can be mounted across two structural components (e.g., portions of a launch vehicle). When the segmented separation structure  101  is commanded to separate, the two structural components can be separated. 
     The separation structure  101  may have a total assembled length of 20 feet or more. That is, each segment  103  forms a portion of the total assembled length of the separation structure  101 . Although shown in  FIG. 1  as a circular separation structure  101 , those of skill in the art will appreciate that separation structures of the present disclosure need not be circular, but rather may take various shapes or configurations, including arcuate, elliptical, linear, etc. 
     Turning now to  FIGS. 2A-2B , a typical segment  221  of a separation device assembly is shown in cross section. The segment  221  may be a portion of a separation device assembly such as that shown in  FIG. 1 . As shown, an expansion device  223  is disposed within a frangible joint  225  which may be an aluminum member having a release portion comprising separation walls  227 ,  229 , which in part define an internal channel, cavity, or chamber for receiving the expansion device  223 . As shown, mounting flanges  231 ,  233  extend from the frangible joint  225  and are each arranged to attach to a portion of a respective structural component. For example, the mounting flanges  231 ,  233  can be designed to fixedly attach or connect two adjacent structural components, as will be appreciated by those of skill in the art. Thus, the mounting flanges  231 ,  233  may be customized to a specific application to properly connect to and join two structural components. That is, although shown as flat mounting flanges  231 ,  233  extending from the frangible joint  225 , those of skill in the art will appreciate that various geometries, shapes, sizes, etc. may be employed for the mounting flanges, which can be dictated by specific applications and/or requirements. In the arrangement of  FIG. 2A , illustrating pre-separation, the frangible joint  225  of the segment  221  can function like a butt plate between two structural components to be separated. 
     The expansion device  223  is positioned lengthwise in the channel formed in the frangible joint  225 . The separation walls  227 ,  229  each have fracture grooves  235 ,  237  that are designed to provide a clean fracture of the separation walls  227 ,  229  in response to expansion of the expansion device  223 . The expansion of the expansion device  223  is achieved by detonation of a charge within an expanding tube assembly  239 . As shown, the expanding tube assembly  239  includes an explosive charge  241  within an explosive charge holder  243 . Activation (detonation) of the explosive charge  241  of the expanding tube assembly  239  will cause the expansion device  223  to expand laterally outward to a substantially circular cross-sectional configuration as shown in  FIG. 2B . As the expansion device  223  expands it will apply force upon the separation walls  227 ,  229  along the length of the segment  221 . The force applied by the expanding expansion device  223  will cause the separation walls  227 ,  227  to break or fail at the fracture grooves  235 ,  237 , thus separating the two mounting flanges  231 ,  233  from each other at the location of the frangible joint  225 . That is, the mounting flanges  231 ,  233  and any associated structural components are separated upon detonation of the expanding tube assembly  239  and expansion of the expansion device  223 . 
     As shown in  FIGS. 2A-2B , the mounting flanges  231 ,  233  are integrally formed with the frangible joint  225  as a unitary body or structure, with the expanding tube assembly  239  located therein. As noted above, the shape, size, dimensions, etc. of the mounting flanges  231 ,  233  are customized to application specifications. Thus, each time a new arrangement of structural component to be separated is designed, a new and specifically customized separation device assembly must be designed and prepared. 
     Embodiments provided herein are directed to modular separation device assemblies that enable different mounting flanges to be installed to a frangible joint, without requiring re-design each time a new configuration is developed. The modular separation device assemblies described herein provide structural integrity and are integral in providing adequate stiffness during function/separation. The frangible joints of the present disclosure are separate from the mounting flanges and are of a uniform design. Thus, the frangible joints may be manufactured in high volume and used for any structural component arrangement, and only customized mounting flanges may be required. 
     Turning now to  FIGS. 3A-3B , schematic illustration of a portion of a separation device assembly  300  is shown.  FIG. 3A  illustrates a cross-section view of the separation device assembly  300  and  FIG. 3B  illustrates an exploded, isometric illustration of the separation device assembly  300 . 
     As shown in  FIGS. 3A-3B , the separation device assembly  300  includes a frangible joint  302 , a first attachable mounting device  304   a,  and a second attachable mounting device  304   b,  with the first and second attachable mounting devices  304   a,    304   b  attached to the frangible joint  302  by one or more fasteners  308 . In some embodiments, the first and second attachable mounting devices  304   a,    304   b  are removably or releasably attached to the frangible joint  302 , and in other embodiments, a fixed or permanent attachment may be employed. As shown, the fasteners  308  are bolts, although other types of fasteners and/or interlocking structures may be employed without departing from the scope of the present disclosure. Further, in some embodiments, rather than physical attachment mechanisms (e.g., fasteners), other types of attachment may be employed, including adhesives, welding, brazing, etc. That is, the fasteners  308  are optional and will depend on the specific arrangement and/or requirements of a particular application. 
     The frangible joint  302  is a modular assembly, and as shown is a two-part arrangement. That is, in accordance with embodiments of the present disclosure, the frangible joint  302  includes a first plate  310   a  and a second plate  310   b.  The first and second plates  310   a,    310   b,  in some embodiments, are identical or symmetrical in shape and structure, although, in some embodiments, one or the other of the plates  310   a,    310   b  may include specific features that are not mirrored in the other of the plates  310   a,    310   b.  The plates  310   a,    310   b  are joinable to form the frangible joint  302 . For example, as shown in  FIG. 3B , the first plate  310   a  includes a first contact surface  314   a  and a second contact surface  316   a  and the second plate  310   b  includes a first contact surface  314   b  and a second contact surface  316   b.  The first and second contact surfaces  314   a,    314   b,    316   a,    316   b  of the two plates  310   a,    310   b  are arranged such that a complete and, in some embodiments, sealed contact is achieved. 
     Each plate  310   a,    310   b  also includes a respective expansion device channel  318   a,    318   b.  The expansion device channels  318   a,    318   b  are arranged to form an expansion device cavity  320  when the plates  310 ,  310   b  are joined together. The expansion device channels  318   a,    318   b  are defined, in part, by respective separation walls  322   a,    322   b  of the plates  310   a,    310   b.    
     As shown in  FIG. 3A , an expansion device  324 , such as an expansion tube, is positioned and contained within the expansion device cavity  320 , e.g., between the separation walls  322   a,    322   b.  The shape and/or geometry of the separation walls  322   a,    322   b  may be configured to accommodate the shape of a corresponding expansion device  324  that is installed within the expansion device cavity  320 . The expansion device  324  may be configured as will be appreciated by those of skill in the art. For example, the expansion device  324  can be filled with a charge (e.g., explosives and/or a fuse) that are arranged to expand upon detonation and apply a force within the expansion device  324 . As noted, the expansion device  324  is contained or held within the expansion device cavity  320  between the two plates  310   a,    310   b,  and in an embodiment, between the separation walls  322   a,    322   b  of the plates  310   a,    310   b.  When the expansion device  324  expands, it will apply a shock and force upon the separation walls  322   a,    322   b  to thus break or separate the frangible joint  302 . Each of the plates  310   a,    310   b  includes a fracture groove  326   a,    326   b  to aid in the separation of the frangible joint  302  when the expansion device  324  expands. 
     The frangible joint  302  is positioned within parts of the first and second attachable mounting devices  304   a,    304   b.  The first attachable mounting device  304   a  includes a frame  328   a  and an attachment element  330   a  that is arranged to attached to or mount the separation device assembly  300  to a first structural component. Similarly, the second attachable mounting device  304   b  includes a frame  328   b  and an attachment element  330   b  that is arranged to attached to or mount the separation device assembly  300  to a second structural component. As shown, the frames  328   a,    328   b  are yolk-shaped, having first and second arms that are arranged to receive portions of the plates  310   a,    310   b  (as described herein). The yolk-shape shown herein is merely for example, and the frames  328   a,    328   b  can take various shapes based on specific needs or requirements for a particular application. Further, the attachment elements  330   a,    330   b  can have any shape and/or configuration to enable attachment and mounting to a structural component, as will be appreciated by those of skill in the art. 
     The frames  328   a,    328   b  each define a respective receiving channel  332   a,    332   b.  The receiving channels  332   a,    332   b  are shaped substantially similar to each other and are arranged to receive end members of the frangible joint  302  such that the assembly of these parts create a required structural integrity of the assembly. For example, as shown in  FIG. 3A-3B , the first plate  310   a  includes a respective first end member  334   a  and a second end member  336   a  and the second end plate  310   b  includes a respective first end member  334   b  and a second end member  336   b.  As shown, the separation walls  322   a,    322   b  extend between the first and second end members  334   a,    336   a,    334   b,    336   b  respectively. The receiving channels  332   a,    332   b  are shaped to receive the end members  334   a,    336   a,    334   b,    336   b,  when the two plates  310   a ,  310   b  are fit together to form the expansion device cavity  320 , as shown. In the present illustrations, the fracture grooves  326   a,    326   b  are positioned between the separation walls  322   a,    322   b  and the first end members  334   a,    334   b.    
     In the embodiment of  FIGS. 3A-3B , the expansion device  324  is positioned within the expansion device cavity  320  using a positioning member  338 . The positioning member  338  can fit within one of the receiving channels, e.g., the receiving channel  332   b  of the frame  328   b  of the second attachable mounting device  304   b,  and/or into a positioning member groove  340  of one or both of the plates  310   a ,  310   b.  Further, the positioning member  338  is held or positioned between the separation walls  322   a,    322   b,  as shown. In some embodiments, the positioning member  338  is positioned equally between the separation walls  322   a,    322   b.    
     As shown, a retaining member  342  can wrap about the expansion device  324  such that upon expansion of the expansion device  324  the expansion device  324  is held or retained with one of the attachable mounting devices  304   a ,  304   b.  In this illustrative embodiment, one of the fasteners  308  passes through an arm or portion of the frame  328   b  of the second attachable mounting device  304   b,  into and through a portion of the retaining member  342 , through the positioning member  338 , again through the retaining member  342 , and out through an opposing arm or portion of the frame  328   b.  In some embodiments, the fastener  308  may also pass through portions of the plates  310   a,    310   b  to retain the plates  310   a,    310   b  within the receiving channel  332   b.    
     Although not shown, a plurality of fasteners  308  may be positioned along an entire length of the separation device assembly  300  to fixedly attach the various components thereof. That is, although shown with only one fastener  308  for the attachment of the first attachable mounting device  304   a  and one fastener  308  for the attachment of the second attachable mounting device  304   b,  those of skill in the art will appreciate that additional fasteners  308  can be employed to secure the attachment therebetween. 
     Turning now to  FIGS. 4A-4B , schematic illustrations of an attachable mounting device  404  in accordance with an embodiment of the present disclosure.  FIG. 4A  is a cross-sectional illustration of the attachable mounting device  404  and  FIG. 4B  is an isometric illustration of the attachable mounting device  404 . The attachable mounting device  404  includes a frame  428  and an attachment element  430 . The attachment element  430  can take any number of configurations (e.g., shapes, sizes, number of features, etc.). The attachment element  430  extends from the frame  428  and is arranged to enable attachment to a structural component. 
     The frame  428  includes a first arm  444  and a second arm  446 . The first and second arms  444 ,  446  define a receiving channel  432  therebetween. The receiving channel  432  is defined by a first arm contact surface  448 , a second arm contact surface  450 , and a channel floor  452 . The first arm contact surface  448 , the second arm contact surface  450 , and the channel floor  452  define a contour or shape that is arranged to receive a portion of a frangible joint, as shown and described above. 
     As shown in  FIG. 4B , the first arm  444  has a fastener aperture  454  and the second arm  446  has respective fastener aperture  456  that aligns with the fastener aperture  454  of the first arm. Thus, a fastener can pass through both fastener apertures  454 ,  456  of the frame  428  and secure a frangible joint within the receiving channel  432 . Also show, the frame  428  includes a positioning member recess  458 , which can be formed in the contour defined by the first arm contact surface  448 , the second arm contact surface  450 , and the channel floor  452 . The positioning member recess  458  is arranged to receive a portion of a position member and/or a portion of a retaining member (e.g., positioning member  338  and/or retaining member  342  shown in  FIGS. 3A-3B ). The positioning member recess  458  may be aligned with the fastener apertures  454 ,  456  to allow for a fastener to also pass through a portion of the positioning member and/or a retaining member. Although shown with a single fastener aperture  454 ,  456  formed in each arm  444 ,  446 , those of skill in the art will appreciate that any number of fastener apertures can be formed with the arms  444 ,  446  of the frame  428 , with each set of fastener apertures arranged to align with apertures of a frangible joint (e.g., components of frangible joint  302  shown in  FIGS. 3A-3B ). 
     Turning now to  FIGS. 5A-5C , schematic illustrations of a plate  510  that forms one half of a frangible joint in accordance with the present disclosure are shown.  FIG. 5A  is a plan view illustration of the plate  510 ,  FIG. 5B  is an isometric illustration of the plate  510  with various components installed therein, and  FIG. 5C  is a cross-sectional or end-on view illustration of the plate  510 . The plate  510  is a segment or portion of a half of a separation device assembly (e.g., a portion of a segment of a segmented separation structure as shown in  FIG. 1 ). 
     As shown, the plate  510  is similar to that shown and described above. That is, the plate  510  includes a first end member  534 , a second end member  536 , and a separation wall  522  extending therebetween. A fracture groove  526  is located between a portion of the separation wall  522  and the first end member  534  to enable breaking or separation of the plate  510  upon expansion of an expansion device  524  (shown in  FIG. 5B ). The plate  510  can sit within a receiving channel of a frame of an attachable mounting device as described above. 
     The first end member  534  defines a first contact surface  514  and the second end member  536  defines a second contact surface  516 . The contact surfaces  514 ,  516  are configured to engage or contact with contact surfaces of a second plate to (not shown) form a frangible joint. The contact surfaces  514 ,  516  are interior surfaces of the plate  510 , when arranged relative to another plate. The end members  534 ,  536  also include exterior engagement surfaces  560 ,  562 , respectively. The engagement surfaces  560 ,  562  are configured to engagement or fit within and match a contour of receiving channel of a frame (e.g., the contour defined by the first arm contact surface  448 , the second arm contact surface  450 , and the channel floor  452  of the frame  428  shown in  FIGS. 4A-4B ). As shown, the engagement surfaces  560 ,  562  are tapered, or angled relative to the contact surfaces  514 ,  516  such that they match the contour of the receiving channel. However, in other embodiments, the engagement surfaces of the end members can have any shape, size, dimension, geometry, engagement/locking features, etc. 
     The separation wall  522  defines an expansion device channel  518  for receiving the expansion device  524  (as shown in  FIG. 5B ). When two plates  510  are joined together, the expansion device channels  518  align to define an expansion device cavity (e.g., expansion device cavity  320  shown in  FIG. 3A ). Further, when two plates are matched together to form a portion of a frangible joint, two positioning member grooves  540  align to house and retain a positioning member  538  and/or a retaining member  542 . 
     Turning not to  FIGS. 6 , a schematic illustration of another embodiment of a separation device assembly  600  in accordance with the present disclosure are shown. The separation device assembly  600  is substantially similar to that shown and described above and thus description of some features will not be repeated. As shown, the separation device assembly  600  includes a frangible joint  602  with first and second attachable mounting devices  604   a,    604   b.  The frangible joint  602  is formed from a first plate  610   a  and a second plate  610   b  that contain an expansion device  624  therein. Each plate  610   a,    610   b  includes a first end member  634   a,    634   b,  second end member  636   a,    636   b,  and separation walls  622   a,    622   b  extending therebetween. In this embodiment, rather than a separate positioning member to position the expansion device  624  in an expansion device cavity, the plates  610   a,    610   b  each include integral positioning arms  664   a,    664   b.  As shown, the integral positioning arms  664   a,    664   b  are integrally formed with the respective end members  636   a,    636   b  of the plates  610   a ,  610   b.  In an embodiment, the arms  664   a,    664   b  each have a planar surface and an opposing tapered surface. The planar surfaces being in contact when the plates  610   a ,  610   b  are assembled. In some embodiments, a combination of integral positioning arms and separate positioning members may be employed, without departing from the scope of the present disclosure. 
     Turning now to  FIGS. 7A-7D , example illustrations of different configurations of attachable mounting devices for separation device assemblies in accordance with the present disclosure are shown. As shown, a first separation device assembly  700 ′ ( FIG. 7A ) has a frangible joint  702 ′ with a first attachable mounting device  704   a ′ and a second attachable mounting device  704   b ′ attached thereto. The first attachable mounting device  704   a ′ has a clevis arrangement and the second attachable mounting device  704   b ′ has an “L” flange arrangement. A second separation device assembly  700 ′ 41   ( FIG. 7B ) has a frangible joint  702 ″ with a first attachable mounting device  704   a ′″ having an “L” flange arrangement and a second attachable mounting device  704   b ′″ having an “L” flange arrangement attached thereto. A third separation device assembly  700 ′″ ( FIG. 7C ) has a frangible joint  702 ′″ with a first attachable mounting device  704   a ′″ having a clevis arrangement and a second attachable mounting device  704   b ′″ having a clevis arrangement attached thereto. A fourth separation device assembly  700 ″″ (FIG. &amp;D) has a frangible joint  702 ″″ with a first attachable mounting device  704   a ″″ having a stock-straight arrangement and a second attachable mounting device  704   b ″″ having a stock-straight arrangement attached thereto. The stock-straight arrangement can be used as-is for attaching to structural components or may be machined or rolled into a desirable geometry for attaching to structural components. 
       FIGS. 7A-7D  are illustrative of the modular nature of the separation device assemblies of the present disclosure. As shown, each of the frangible joints  702 ′,  702 ″,  702 ′″,  702 ″″ is the same as the others, illustrating the uniform nature and interchangeability of attachable mounting devices. Any combination of attachable mounting devices can be employed to suit a given scenario. Further, although illustratively shown with the frangible joints  702 ′,  702 ″,  702 ′″,  702 ″″ having integral positioning arms, as shown and described above, the specific structure and/or arrangement of the frangible joints can be any of the above described embodiments and/or variations thereon. 
     That is, the attachment elements of the attachable mounting devices of the present disclosure can take any shape, geometry, and/or orientation, and yet still be attachable to a standard or universal frangible joint due to engage with the frames of the attachable mounting devices. Stated another way, the frames of the attachable mounting devices are also uniform or universal and the attachment elements are variable. In some embodiments, only the interior contour of the frame (e.g., the receiving channel) of the attachable mounting devices need be uniform, and the exterior surfaces thereof can be arrange or designed for specific applications, if required. 
     Advantageously, embodiments described herein provide frangible joints that can be manufactured in high quantities, regardless of the specific application for joining (and then separating) structural components (e.g., components of spacecraft, launch vehicles, etc.). That is, frangible joints in accordance with embodiments of the present disclosure can be manufactured to a specific, standard design. To then use the universal frangible joints, modular attachment features can be customized and attached to the universal frangible joints. For example, differently configured and/or arranged attachable mounting devices can be selected to cater to a specific application or structural component. 
     Components of the present disclosure, including the plates of the frangible joints and/or the attachable mounting devices can be fabricated using various techniques. For example, machining, extruding, and/or additive manufacturing can be employed without departing from the scope of the present disclosure. 
     The frangible joints of the present disclosure, in one non-limiting example, are low profile, two-plate frangible joint structural assemblies with modular vehicle attachment features. Symmetrical frangible joint features (e.g., end members, contact surfaces, separation walls, etc.) and/or symmetrical features of the frames of the attachable mounting devices can simplify and/or standardize manufacturing processes, thus reducing costs. Further, such standardization allows for customization of only the attachment elements, which can further reduce costs associated with manufacturing separation structures as compared to prior arrangements where the entire segmented separation structure was manufactured (start to finish) for a specific and particular application, which can be costly. 
     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.