Patent Application
20150259081
Spacecraft, satellites, and other structures (hereinafter “space structures”) orbiting in space outside of the Earth's atmosphere are subjected to various environmental hazards. One such hazard includes the potential for impact with objects or debris traveling at hypervelocity speeds. Even very small particles colliding with a space structure have the potential to cause significant damage due to the speed at which the particles are moving.
To minimize damage to a space structure from impacts with debris in space, the structure may be protected with a Whipple shield, which consists of two plates that are spaced apart. When the debris impacts and penetrates the outermost plate, the debris cloud from the impact spreads out between the plates before being absorbed by the second plate. However, as the Whipple shield provides no structural purpose for the associated space structure, it is positioned externally to the walls or surfaces of the structure to be protected. In doing so, the Whipple shield increases the thickness of the walls and adds weight, neither of which is desirable since minimizing the size and weight of space structures are primary considerations when launching the structures into orbit.
It is with respect to these considerations and others that the disclosure made herein is presented.
It should be appreciated that this Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to be used to limit the scope of the claimed subject matter.
Systems, methods, and apparatus described herein provide for a structural armor that provides load-bearing support to a space structure, as well as providing protection against hypervelocity impacts. According to one aspect of the disclosure provided herein, a structural armor includes a front armor facesheet and a rear armor facesheet offset from the first. An angular member core occupies the space between the front armor facesheet and the rear armor facesheet. The angular member core includes a number of nodes abutting the front armor facesheet and the rear armor facesheet. A number of angular members intersect at an acute node angle from the front armor facesheet or the rear armor facesheet. The acute node angle is selected according to a spread angle of a debris field resulting from a hypervelocity impact of an object with the front armor facesheet. The angular member core is configured to provide load-bearing capability for a structure.
According to another aspect, a method of protecting a space structure from an impact with an object moving at hypervelocity speed includes receiving a penetrating impact from the object on a front armor facesheet of a structural armor. Debris from the penetrating impact is conically distributed outward at a spread angle through an angular member core to a rear armor facesheet of the structural armor.
According to yet another aspect, a method of providing a structural armor for protecting a space structure from an impact with an object moving at hypervelocity speed is provided. The method includes configuring an angular member core with a number of nodes and a number of angular members intersecting at the nodes according to acute node angles from a front armor facesheet or a rear armor facesheet. The acute node angles correspond to a spread angle of a debris field resulting from a hypervelocity impact of an object with the front armor facesheet. The front armor facesheet and the rear armor facesheet are coupled to the angular member core such that the angular members extend from the front armor facesheet to the rear armor facesheet.
The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.
The following detailed description is directed to apparatus and methods corresponding to a structural armor that provides structural support to a spacecraft or other structure, as well as providing protection against hypervelocity impacts. References are made to the accompanying drawings that form a part hereof, and which are shown by way of illustration, specific embodiments, or examples. Like numerals represent like elements through the several figures.
As discussed briefly above, space structures are vulnerable to damage caused by objects travelling through space at hypervelocity speeds. Whipple shields may provide some degree of protection to these types of impacts, but undesirably add to the thickness of the walls of the space structure being protected, while offering no structural or load-bearing benefits.
When the object 104 penetrates the front facesheet 106, a debris field 112 spreads outward from the front facesheet 106 towards the rear facesheet 108 in substantially a conical shape, as shown in
One method of attempting to provide protection to a space structure without adding an additional plate or plates externally to the walls of the structure includes utilizing a honeycomb sandwich structure to provide structural support, as well as to absorb impacts from an object 104 moving at hypervelocity speeds.
However, after impact with the object 104, the cells 206 bounded by the cell walls 208 create a channeling effect with the debris field 112. The channeling effect essentially constrains the debris field 112 in a manner that prevents the cone of debris from spreading outward to the degree that is prevalent with the Whipple shield 102. As can be seen in the comparison between the honeycomb structure 202 and the Whipple shield 102, the spread angle 116 of the debris field 112 is greater with the honeycomb structure 202 than the corresponding spread angle 116 of the debris field 112 of the Whipple shield 102. As a result, the rear contact area C associated with the honeycomb structure 202 is smaller than the rear contact area B of the Whipple shield 102. The smaller contact area does not allow for the degree of energy dissipation of the debris field 112 as is achieved with the Whipple shield 102. It should also be noted that filling the space between the front facesheet 106 and the rear facesheet 108 with a material such as aluminum foam rather than the honeycomb structure 202 may also be done to provide some degree of protection from hypervelocity impacts. However, the random internal structure of aluminum foam would not be effective in providing an optimal spread angle 116 of the debris field 112 and would increase the weight of the corresponding structure as compared to the concepts described below.
Looking now at
According to one embodiment described in detail below with respect to
According to various embodiments, the acute node angle 316 may be approximately equivalent to or greater than the spread angle 116 of the debris field 112 resulting from the impact and penetration of the object 104 with the front armor facesheet 306. In doing so, the angular member core 304 eliminates or mitigates the channeling effect described above with respect to the honeycomb structure 202, allowing the debris field 112 to conically expand to the rear contact area D, which is similarly sized to the rear contact area B of the Whipple shield 102. It should become clear from this discussion that the structural armor 302 described herein is capable of dissipating the energy from an impact with an object 104 to a greater capacity than is capable with the Whipple shield 102, while additionally providing load-bearing capabilities that enable the structural armor 302 to be used as a load-bearing component of a space structure 110 as opposed to being mounted to an external surface of a load-bearing component of the space structure to serve as protection only.
Turning now to
It should be understood that the configuration of the angular member core 304 is not limited to the specific example shown and described with respect to
This configuration of the angular member core 304 in which the angular members 310 intersect at nodes 312 and extend from the front armor facesheet 306 and from the rear armor facesheet 308 at acute node angles 316 substantially differs from the configuration of the honeycomb core 204 described above in which the cell walls 208 extend parallel to one another between the front and rear facesheets. The benefits of the structural armor 302 with the angular member core 304 over the honeycomb structure 202 with the honeycomb core 204 lie first in the acute node angle 316. As previously discussed, the acute node angle 316 allows the debris field 112 to conically expand to the rear contact area D, which is similarly sized to the rear contact area B of the Whipple shield 102. In sum, the angular member core 304 eliminates or mitigates the channeling effect described above with respect to the honeycomb structure 202.
In configuring the structural armor 302, the mission parameters of the particular application will drive the specific configuration of the front armor facesheet 306, the rear armor facesheet 308, and the angular member core 304. As will be described in greater detail below with respect to
In addition to allowing for an optimum spread angle 116 of the debris field 112, the configuration of the structural armor 302 with the angular member core 304 provides additional benefits over the honeycomb structure 202 and over the Whipple shield 102 via the positioning of the angular members 310 within the core. Specifically, by originating multiple angular members 310 at each of the nodes 312 and extending each angular member 310 at the acute node angle 316 to another node 312 on the opposite facesheet, the angular members 310 effectively “criss-cross” throughout the space between the front armor facesheet 306 and the rear armor facesheet 308. By occupying this space, in contrast to the substantial open space of the cells 206 of the honeycomb core 204 or the completely open space within the Whipple shield 102, there is an increased likelihood that the debris field 112 will contact portions of the angular members 310, which further dissipates energy from the debris field 112 as it spreads conically outward towards the rear armor facesheet 308.
As can be seen in the energy graph 602 and corresponding legend 604, lines of various patterns represent plots of the kinetic energy over a time period for impacts at a node 312, beam 502, valley 504, and aperture 506 corresponding to
Looking at the energy plots in detail, period A represents the approximate time during which the object 104 travels through the front armor facesheet 306, or in the case of the honeycomb structure 202 and Whipple shield 102, the front facesheet 106. Period B of the energy graph 602 represents the approximate time through which the debris field 112 travels between the front and rear facesheets. Period C represents the approximate time during which the debris field 112 impacts and penetrates the rear armor facesheet 308, or in the case of the honeycomb structure 202 and Whipple shield 102, the rear facesheet 108. Period D represents the time after the debris field 112 penetrates the rear armor facesheet 308 or the rear facesheet 108.
In period A, all energy plots show a decrease in kinetic energy since the energy is absorbed by the applicable facesheet. As seen in period D, the kinetic energy continues to gradually decline for all energy plots after the debris field 112 penetrated the rear armor facesheet 308 or rear facesheet 108; however, it should be appreciated that the characteristics of the actual energy plot would depend upon the space structure 110 into which any remaining debris field 112 enters after leaving the facesheet. For illustrative purposes, the periods B and C will now be described with respect to the Whipple shield 102 and the honeycomb structure 202. These periods of the energy graph 602 will then be discussed with respect to the various impact areas of the structural armor 302 for comparison purposes to highlight advantages of the structural armor 302 over the Whipple shield 102 and the honeycomb structure 202.
As stated above, period B of the energy graph 602 shows the various energy plots corresponding to the debris field 112 passing between the front and rear facesheets. With respect to the Whipple shield 102, the kinetic energy of the debris field 112 decreases very little in period B after penetrating the front facesheet 106. The reason for this minor decrease is that the debris field 112 is conically expanding between the facesheets, but because there is no structure between the facesheets, there is no substantial energy loss before contact with the rear facesheet 108. With respect to the honeycomb structure 202, the energy within period B is slightly lower than the energy associated with the Whipple shield 102 since portions of the debris field 112 may impact the cell walls 208 within the honeycomb core 204.
Period C represents the approximate time during which the debris field 112 impacts and penetrates the rear facesheet 108. For both the Whipple shield 102 and the honeycomb structure 202, the kinetic energy of the debris field 112 decreases due to the impact with the rear facesheet 108. However, the Whipple shield 102 is more effective than the honeycomb structure 202 in dissipating energy due to the channeling effect of the honeycomb core 204, as described above with respect to
In contrast, each impact location of the structural armor 302 provides for greater energy dissipation in periods B and C as compared to the Whipple shield 102 and honeycomb structure 202, particularly with respect to impacts at a node 312, beam 502, or valley 504. Impact at a node 312 provides the greatest degree of energy dissipation according to this example, although impacts at a beam 502 or valley 504 provide similar energy dissipation performance. It should be appreciated that the characteristics of the energy dissipation for impacts at a node 312, beam 502, and valley 504 within period C is similar to that of the Whipple shield 102. As discussed above, the angular member core 304 of the structural armor 302 includes acute node angles 316 similar to the spread angle 116 of the debris field 112 of a Whipple shield 102. In doing so, the angular member core 304 allows the debris field 112 to conically expand to the rear contact area D, which is similarly sized to the rear contact area B of the Whipple shield 102.
The energy plot associated with an impact at an aperture 506 is similar to that of the honeycomb structure 202, although with improved energy dissipation characteristics. Because of the aperture 506, the impact is similar to that of the Whipple shield 102 since there are no angular members 310 directly in the path of the debris field 112. However, the spread angle 116 of the debris field 112 may be somewhat limited due to the angular members 310 adjacent to the aperture 506, which may create limit the size of the rear contact area in a similar way as described above with respect to a honeycomb core 204. Because of the limited probability of an impact directly in the center of an aperture 506 of the angular member core 304, there is a greater likelihood of an energy plot associated with the node 312, beam 502, valley 504, or combination thereof.
Turning now to
From operation 702, the routine 700 continues to operation 704, where a front armor facesheet 306 is coupled to the front nodes 312A. It should also be appreciate that the “coupling” may include creating the front armor facesheet 306, rear armor facesheet 308, and the angular member core 304 out of a single piece of material. Accordingly, the coupling may include any known method of bonding or creating the structural armor 302 configuration, including but not limited to brazing, casting, adhesives, laser cutting, 3D printing, mechanical folding/manipulation, or any combination of these or other known processes. At operation 706, the rear armor facesheet 308 is coupled to the rear nodes 312B in a manner similar to that used for coupling the front armor facesheet 306 to the angular member core 304.
The routine 700 continues to operation 708, where the structural armor 302 is configured as part of a space structure 110, and the routine 700 ends. As discussed above, the structural armor 302 provides load-bearing capabilities in order to provide a structural benefit to the space structure 110. In this manner, the structural armor 302 may be used as a wall or other load-bearing component rather than externally attached to the space structure 110, which would increase the weight and thickness of the space structure 110.
Because of the angled configuration of the angular members 310 between the facesheets, the debris field 112 impacts one or more angular members 310 at operation 806. This impact is effective in further dissipating the kinetic energy from the debris field 112 as it travels toward the rear armor facesheet 308. At operation 808, the debris field 112 impacts the rear armor facesheet 308. Because of the acute node angle 316 of the angular member core 304, the resulting spread angle 116 of the debris field 112 provides for a rear contact area D that is larger than a corresponding rear contact area C of a honeycomb structure 202, allowing for increased energy dissipation. After the debris field 112 impacts the rear armor facesheet 308, the routine 800 ends.
It should be clear from the disclosure above that the technologies described herein provide for a structural armor 302 that may be efficiently and effectively used to provide both a load-bearing capability for a space structure 110, as well as enhanced protection against hypervelocity impacts from objects 104 in space. The configuration of the angled member core 304 having nodes 312 and angled members 310 criss-crossing between the facesheets according to acute node angles 316 simultaneously allows for optimum conical expansion of the debris field 112, while providing additional barriers in the path of the debris field 112 to further dissipate the kinetic energy prior to contact with the rear armor facesheet 308.
The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes may be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the present invention, which is set forth in the following claims.
