Lattice-like structures for vibration control in dynamic environments.

Abstract

Embodiments of the present disclosure relate to vibration control systems and devices for structurally isolating a load from a vibration source. In various embodiments, the vibration isolator includes first and second support structures and a sidewall extending therebetween and defining a body of the vibration isolator. In embodiments, the sidewall is configured to structurally support the load. In embodiments, the sidewall includes one or more lattice sections occupying at least a portion of a total area of ​​the sidewall, the lattice sections configured to damp transmission of vibrations through the sidewall between the first and second support structures to reduce vibration transmission from spacecraft vibration sources and loads. In embodiments, the body of the vibration isolator is substantially the same as a part without the one or more lattice sections such that the payload interface cone is a drop-in replacement.

Description

[Technical field]

[0001] Various embodiments of the present disclosure relate to vibration control, and more particularly, to lattice structures for vibration control in whole spacecraft isolation systems. [Background technology]

[0002] Vibration control is an increasingly important attribute for components used in sectors such as the automotive, aerospace, construction, and biomedical industries. Generally speaking, vibration refers to the periodic reciprocating motion that is widespread in nature and occurs for a variety of reasons, including motion, shock, and sound. When vibration exceeds certain limits, it can cause harm to equipment, components, structures, and even the human body. As a result, this kind of excessive vibration can cause many engineering problems, including structural failure, failure of precision equipment, and destruction of various electronic components.

[0003] The application of vibration mitigation methods, devices, and materials has expanded to various fields such as civil engineering, mechanical engineering, and aerospace engineering. For example, in the field of aerospace engineering, multi-dimensional vibration control has become an important consideration to ensure the safety of satellite payloads or other equipment during the launch phase. Vibrations during launch are typically generated by flight events such as engine ignition, booster separation, and acoustic excitations, and the frequency range of each of these excitations may be different. As a result, vibration mitigation generally requires the ability to mitigate vibrations occurring over a wide range of frequencies.

[0004] Generally, vibration mitigation in spacecraft includes both whole-spacecraft vibration isolation and micro-vibration control. Whole-spacecraft vibration isolation refers to methods and apparatus for reducing vibration loads during launch to reduce the risk of damage to the spacecraft and its equipment before entering orbit. The launch phase is the most severe dynamic environment a spacecraft experiences during its mission. To survive this phase, the spacecraft structure is generally strengthened by adding mass / structure that becomes useless once the spacecraft is in orbit. This not only increases launch costs but also reduces the margin of mass that can be used to launch additional payloads. Micro-vibration control refers to methods and apparatus for reducing the risk of damage to equipment or components from post-launch vibrations while the spacecraft or satellite is in orbit. Both passive and active vibration control systems are used, but active vibration control systems generally demonstrate vibration control performance at a higher cost and complexity.

[0005] Over the past several decades, researchers have been working towards vibration mitigation methods, devices, and materials for spacecraft and other applications. For example, "Active Vibration Control System for Total Spacecraft Vibration Isolation" (2009) discloses an active vibration control system for total spacecraft vibration isolation that includes multiple isolators inserted between a launch vehicle and a payload adapter. In addition, a passive constrained layer damping (PCDL) material is attached to the outer surface of the payload adapter.

[0006] Non-Patent Document 2 discloses a full spacecraft active isolation system based on a voice coil motor (VCM). The system of Non-Patent Document 2 includes a VCM, a support leaf spring, and an actuator support disposed between the launch vehicle and the payload adapter. Therefore, the system of Non-Patent Document 2 can meet the design requirements for vibration isolation by adding the VCM and related parts without modifying the payload adapter mounting structure itself.

[0007] Non-Patent Document 3 discloses an active payload adapter for reducing interface loads to the payload in the low frequency range (<100 Hz). The adapter in Non-Patent Document 3 consists of two interface rings connected by 24 active struts. The transmission of dynamic loads to the launcher is via a structural path through the payload adapter, which forms a structural connection from the launcher payload to the launcher.

[0008] (2003) presents an octostrut passive vibration isolation platform to replace existing payload mounting brackets to provide an interface between a launch vehicle and a spacecraft.

[0009] Non-Patent Document 5 presents a Circular Payload Adapter Fitting (CPAF) that integrates passive and active vibration control with a piezoelectric stack actuator.

[0010] Non-Patent Document 6 presents a voice coil motor that is designed and optimized as an active control actuator that provides appropriate feedback forces to reduce the amplitude of vibrations and is fixed to the entire spacecraft vibration isolation platform, with sensors positioned vertically on one side of the voice coil motor.

[0011] As seen in Non-Patent Document 3 and Non-Patent Document 4, researchers have explored the use of strut-based structures to improve the mechanical vibration isolation properties of machine frames and reduce weight while maintaining structural integrity. However, in the case of the device in Non-Patent Document 3, the vibration control device is designed as an active device that relies on hydraulic struts configured to adjust to control vibration. The use of active vibration control devices adds cost and complexity to the design, along with an increased possibility of component failure due to vibration control components. In Non-Patent Document 4, the device applies the design concept of the Stewart platform for total spacecraft passive vibration isolation. The device in Non-Patent Document 4 adds redundancy to the traditional Stewart platform design by adding redundant struts to the platform for safety and reliability.

[0012] Outside the specific field of spacecraft, researchers have explored using additive manufacturing or 3D printing to create strut-based structures to improve the mechanical vibration isolation properties of machine frames. For example, “Additive Manufacturing of 3D Printed Strut-Based Structures for Vibration Isolation” (2013) presents an additively manufactured lattice design for use in vibration isolation structures.

[0013] There remains a need to continually research and improve the properties of vibration mitigation materials, and therefore improvements to vibration mitigation and control systems would be well received. [Prior art documents] [Non-patent literature]

[0014] [Non-Patent Document 1] Jun et al., "An evaluation of the whole-spacecraft passive vibration isolation system," Proc. Inst. Mech. Engineers Part G J. Aerospace Eng., 2007, 221, pp. 67-72. [Non-Patent Document 2] Tang et al., "Design and experimental study of a VCM-based whole-spacecraft vibration isolation system," J. Aerospace Eng., 2018. [Non-Patent Document 3] Rittweger et al., "Feasibility demonstration of an active payload adapter for Ariane 5," Spacecraft Structures, Materials and Mechanical Testing 2005, 2005, p. 581. [Non-Patent Document 4] Liu et al., "Octo-strut vibration isolation platform and its application to whole spacecraft vibration isolation," J. Sound Vibration 289, 2006, pp. 726-744. [Non-Patent Document 5] Liu, F., Fang, B., and Huang, W. H. (2010), "Vibration control of flexible satellites using a new isolator", In 2010 3rd International Symposium on Systems and Control in Aeronautics and Astronautics Harbin, IEEE, 2010, pp. 593-597. [Non-Patent Document 6] Chi et al., "Design of active whole-spacecraft vibration isolation based on voice-coil motor," Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, 2014, No. 9061, pp. 90613X1-90613X-7. [Non-Patent Document 7] Syam et al., "Design and Analysis of Strut-Based Lattice Structures for Vibration Isolation," Precision Engineering, 2017. [Brief description of the drawings]

[0015] The drawings included in this application are incorporated in and form a part of this specification. The drawings illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The drawings are merely illustrative of certain embodiments and are not intended to be limiting of the disclosure. [Figure 1A] FIG. 1 illustrates a vibration control device in accordance with one or more embodiments of the present disclosure. [Figure 1B] FIG. 1 illustrates a vibration control device in accordance with one or more embodiments of the present disclosure. [Figure 2A] FIG. 1 is a schematic diagram of a vibration control device in accordance with one or more embodiments of the present disclosure. [Figure 2B] 11 is a graph illustrating the effect of vibration control in accordance with one or more embodiments of the present disclosure. [Figure 3A-3F] 1A-1D illustrate various embodiments of a cylindrical vibration control device in accordance with one or more embodiments of the present disclosure. [Figure 4] FIG. 1 illustrates a prior art spacecraft system. [Figure 5A] 1A-1D illustrate various embodiments of a total spacecraft isolation system including one or more vibration control devices in accordance with one or more embodiments of the present disclosure. [Figure 5B] 1A-1D illustrate various embodiments of a total spacecraft isolation system including one or more vibration control devices in accordance with one or more embodiments of the present disclosure. [Figure 6A] FIG. 6 illustrates an additional embodiment of a spacecraft isolation system 600B including one or more vibration control devices, in accordance with an embodiment of the present disclosure. [Figure 6B] FIG. 6 illustrates an additional embodiment of a spacecraft isolation system 600B including one or more vibration control devices, in accordance with an embodiment of the present disclosure. [Figure 7A] FIG. 1 illustrates a method for installing a vibration control device in accordance with one or more embodiments of the present disclosure. [Figure 7B] 1 is a graph illustrating vibration amplitudes to which a load may be subjected over a range of vibration frequencies. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] While the embodiments of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

[0017] (overview) One or more embodiments of the present disclosure relate to a tuned lattice attenuator and a method for tuning the lattice attenuator for customized dynamic mechanical loading.

[0018] In various sectors such as automotive, aerospace, construction, and biomedical industries, dynamic environments such as shock, vibration, and acoustics can be important design constraints. For example, especially in aerospace applications, dynamic environments can cause the most damaging loading events to on-board electronics, avionics, munitions, pneumatic components, etc., affecting functionality or causing damage to components. As a result, dynamic environments can sometimes result in failure of the entire system due to damage to one or more critical components.

[0019] Generally, there are several approaches to address the problems posed by dynamic environments. These approaches include designing the hardware to be more resistant to the dynamic environment or isolating the hardware from the dynamic environment using mechanical interfaces. However, in many cases, it is not possible to design the hardware to withstand the dynamic environment due to technical constraints, schedule or cost constraints, or the severity of the dynamic environment.

[0020] Therefore, isolation systems are more frequently used for vibration control. However, isolation systems have their own drawbacks. For example, multiple isolators may be required to protect a particular component. Depending on the weight of the hardware being supported, the isolators themselves need to be properly selected and sized based on the natural frequency of the hardware being supported. Additionally, mounting hardware is also required to secure each isolator. This includes fasteners, washers, and supports as needed. This increases the amount and complexity of the components, increasing the mass of the system. As another example, once a component is isolated, it is no longer fixed to the board, which means it is more susceptible to adverse temperature changes. To protect the component, heat sink brackets or other thermal management systems may be required. These increase design and manufacturing costs.

[0021] Furthermore, when a part is isolated, it may lose its electrical ground path. This means that metal ground straps may be required for all parts, especially avionics or other electronics. Furthermore, acceptance testing of the isolators themselves is often required to verify / validate the performance of the lot. The isolators are then tagged as a set to be installed together, which requires tracking and verification. Finally, larger systems such as aircraft, amphibious vehicles, underwater vehicles, and launch vehicles may have dozens, if not hundreds, of parts that require isolation. This adds significant costs in labor, documentation, and tracking requirements that are individually small, but can add up at the system level. Aside from cost, this creates a significant amount of "parasitic mass" throughout the system, i.e. mass that is only there to reduce the dynamic environment. Parasitic mass results in efficiency losses in applications that are less sensitive to mass, but can be a significant concern in applications that are more sensitive to mass, such as spacecraft design. Ultimately, all of these activities can contribute to longer manufacturing schedules.

[0022] In consideration of these issues, various embodiments of the present disclosure provide dynamic environmental isolation / vibration control devices that can address the problems inherent in existing isolation systems. In one or more embodiments, the dampener comprises a lattice support structure that can be used to mitigate the dynamic environment in a system by isolating connected elements from vibration sources. Furthermore, in various embodiments, due to the nature of the lattice structure, the embodiments can function as drop-in replacements for existing structures or parts in a system that provide vibration damping / vibration control while also maintaining the same or similar structural strength as the replaced structure / part. Thus, various embodiments allow for "plug and play" use in existing / legacy systems without requiring redesign or significant modification. For example, in various embodiments, an existing legacy part can simply be removed and replaced by an embodiment of the present disclosure that maintains similar shape, size, and structural characteristics to support loads, but includes inherent vibration damping / isolation properties as a result of the lattice structure / lattice design, as opposed to the replaced part.

[0023] Because the lattice support structure provides inherent vibration control, various embodiments may completely eliminate the need for isolation at an individual or local level. Depending on the application, components may be bonded or rigidly mounted to the lattice support structure, thereby eliminating the need for isolators, supports, associated mounting hardware, brackets, ground straps, etc. For example, the avionics cylinders of the Minotaur IV S4 rocket require over 200 individual isolators, which represents a large overall system parasitic mass.

[0024] In one or more embodiments, the parasitic mass of these traditional vibration isolators is eliminated. As a result, various embodiments may provide improved performance capabilities and significantly reduce costs. For example, embodiments may improve the payload capacity of a launch vehicle by reducing parasitic mass. For example, certain embodiments may increase payload capacity by 13%. In addition, various embodiments may result in significant reductions in design costs due to simplification or elimination of vibration control analysis. Similarly, the "plug and play" nature of various embodiments may shorten and / or standardize manufacturing schedules. For example, a soft ride system used to reduce vehicle transient loads on a spacecraft may increase development costs from $300,000 to $600,000 and add 12-18 months of development time. In various embodiments, these costs and added development time may be significantly reduced or eliminated. For example, various embodiments may result in approximately 16% cost reduction in a launch vehicle.

[0025] Accordingly, one or more embodiments relate to a vibration control system for total spacecraft vibration isolation. In various embodiments, the system comprises a payload interface cone for connection between a spacecraft vibration source and a load. In various embodiments, the payload cone includes a first support structure, a second support structure, and a sidewall extending between the first support structure and the second support structure and defining a frusto-conical body of the payload interface cone. The sidewall is configured to structurally support the load against the second support structure such that the load is isolated from the spacecraft vibration source. In one or more embodiments, the sidewall includes one or more lattice sections occupying at least a portion of a total area of ​​the sidewall. In various embodiments, the lattice sections are configured to damp transmission of vibrations through the sidewall between the first support structure and the second support structure to reduce vibration transmission from the spacecraft vibration sources and loads. In various embodiments, the frusto-conical body of the payload interface cone is substantially the same as a part without the one or more lattice sections such that the payload interface cone is a drop-in replacement part. In certain embodiments, the system does not include a separate damping device, such as a spring, for vibration damping.

[0026] The above summary is not intended to describe each illustrated embodiment or every embodiment of the present disclosure. 1A-1B, vibration control devices 100A, 100B are shown according to one or more embodiments of the present disclosure. In various embodiments, the vibration control devices 100A, 100B are structural components of a vibration isolation system that functions to physically support and / or isolate the load 104 from the vibration source 106 to protect the load 104 from potential vibration damage. In such embodiments, the vibration control devices 100A, 100B are sub-components or subsystems of a larger system in which the supported load 104 is isolated or protected from a dynamic environment. For example, in various embodiments, the devices 100A, 100B are part of an overall spacecraft isolation system configured to isolate an attached payload contained in a launch spacecraft. However, this is merely an exemplary use, and in various embodiments, the devices 100A, 100B can be components of any suitable type of vibration isolation system, such as those used in automobiles, medical equipment, or other types of systems. In one or more embodiments, the supported load 104 is connected to the vibration source 106 only through the devices 100A, 100B. However, in certain embodiments, the supported load 104 may be supported by multiple vibration control devices or other structural components. In some embodiments, the vibration device may be directly connected to the load 104 or indirectly connected such that one or more other components may be disposed between the device and the load itself.

[0027] In various embodiments, the vibration control device 100A, 100B includes one or more structural features that suppress or damp the transmission of vibration from the vibration source 106 to the supported load 104. Thus, when connected to the device 100A, 100B, the load 104 will generally have a reduced vibration amplitude 108 relative to the vibration amplitude 110 at the vibration source 106. For example, with further reference to FIGS. 2A-2B, a schematic diagram of a vibration control device 204 and a graph showing the effect of vibration control are shown, according to one or more embodiments of the present disclosure. With specific reference to FIG. 2A, a simple example is shown in which vibration is transmitted from an external vibration source 206 to a load 208, which in various embodiments may be a machine, structure, or other system component that requires some degree of protection from a dynamic environment.

[0028] In such embodiments, the load 208 is protected from the vibration source 206 via a vibration control device 204 that supports the load 208 and reduces the effect of the source vibration 210 on the supported load 208. For example, in various embodiments, the device 204 is comprised of a structure having structural properties and / or materials that function to isolate, damp, or otherwise attenuate the transmission of the source vibration 210 to the load 208. For example, as shown in FIG. 2A, the device 204 functions as both an isolator 212 and a dampener 214. For example, in various embodiments, the isolator 212 can be used to reduce the vibration amplitude 216 transmitted to the machine in response to external vibrations by isolating the load 208 from the external vibration source 206. In one or more embodiments, the ratio of the reduced vibration 216 seen by the load 208 to the source vibration 210 indicates the degree of isolation from the external vibrations. In various embodiments, the dampener 214 has a damping factor that may be the result of damping components / materials or may result from the construction of the device 204 itself.

[0029] The vibration control results are illustrated in graph 220 of Figure 2B, which considers two scenarios in which vibration is transferred from a vibration source 206 to a load 208 by different embodiments of the vibration control device 204. For example, graph 220 considers a first embodiment 222 in which the vibration control device 204 is configured as an isolator but does not include damping properties, and a second embodiment 224 in which the vibration control device 204 is configured as an isolator and includes damping.

[0030] In FIG. 2B, the y-axis represents the ratio 226 of the vibration amplitude experienced by the load 208 to the vibration amplitude experienced by the vibration source 206, and the x-axis represents the ratio 226 of the frequency f of the vibration experienced by the load 208 to the natural frequency f of the load 208. n , and the natural frequency f is expressed as a ratio 228 between f and the natural frequency f. Thus, in one or more embodiments, if the fraction of displacement transferred to the load is equal to 1, the load 208 is considered to be one structure with the external vibration source 206 since the load 208 experiences the same vibration amplitude as the vibration source. Furthermore, in various embodiments, the natural frequency f is expressed as a ratio 228 between f and the natural frequency f. n When the ratio between the load 208 and the vibration amplitude ratio 226 is equal to 1, the vibration amplitude of the load 208 will be amplified due to the effects of natural resonance. Thus, as shown in Figure 2B, the first and second embodiments of the device 204 function as vibration isolators by reducing the vibration amplitude ratio 226 to less than 1 as the vibration ratio 228 moves away from the resonant frequency of the load. Figure 2B further shows that in the second embodiment 224, the vibration damping properties of the device 204 function to reduce the maximum vibration amplitude ratio 226 near the resonant frequency as compared to the undamped embodiment 222.

[0031] As described further below, in various embodiments, the device 204 is configured to vibrate at a natural frequency f of the attached load 208. n In such an embodiment, the natural frequency f nBy shifting the natural frequency, the maximum vibration amplitude 226 experienced by the load 208 can be shifted to a desired frequency (e.g., a frequency at which the load 208 can best tolerate vibration forces). For example, the attached load 208 may have a higher tolerance to vibrations located at a particular wavelength, and by shifting the natural frequency to that wavelength, the load can be protected through a maximum vibration amplitude occurring where the load is best suited to withstand the vibrations.

[0032] As shown in Figures 1A and 1B, the devices 100A, 100B are configured as lattice vibration control devices. The inventors have determined that the lattice structure provides a highly efficient vibration isolation structure that still exhibits sufficient structural integrity to support loads. Thus, in various embodiments, the lattice sidewall design is utilized to replace a portion of an existing part or to create a new part that has the same size / shape and the same or similar structural integrity as the previous part, but with vibration control properties built into the part itself. Thus, various embodiments can function as a drop-in replacement for an existing structure or part in a system, providing vibration damping / control while also maintaining the same or similar structural strength as the replaced structure / part.

[0033] In one or more embodiments, the apparatus 100A, 100B includes a frame structure including a first support structure 120 and a second support structure 122 that are attached to the vibration source 106 and the supported load 104, respectively. In various embodiments, the first and second support structures 120, 122 are generally solid portions of the apparatus configured to be attached to the load 104 and / or the vibration source 106. Thus, in various embodiments, the support structures may also be referred to as the upper or lower portions of the apparatus, or support platforms, or the like. In various embodiments, the apparatus 100A, 100B includes lattice-like side walls 126A, 126B that constitute the body of the apparatus and connect the first and second support structures 120, 122. In such embodiments, the side walls 126A, 126B are configured to support a structural load applied to the first and second support structures 120, 122 (e.g., to support a load on the vibration source).

[0034] In various embodiments, the lattice sidewalls 126A, 126B include one or more lattice sections 130 that occupy at least a portion of the total area of ​​the sidewalls 126A, 126B. In various embodiments, the lattice sections 130 are configured to damp the transmission of vibrations 132 between the first support structure 120 and the second support structure 122 by blocking the transmission of vibrations 132 through the connecting sidewalls 126A, 126B. Thus, in one or more embodiments, the lattice design improves and / or changes the isolation / damping properties of the device. For example, in certain embodiments, the isolator can shift the natural frequency of the attached load as well as control the device to damp vibrations in a specific manner to keep the attached load within an acceptable vibration threshold.

[0035] Specifically, as shown in FIG. 1A, for example, when the device is configured as a cylindrical support, the device includes sidewall 126A having a generally cylindrical shape, while as shown in FIG. 1B, for example, when the device is configured as a payload cone or as a bulkhead, sidewall 126B has a frustoconical shape.

[0036] As shown in FIGS. 1A-1B, the sidewalls 126A, 126B include a plurality of lattice sections 130 defined as sections of the lattice sidewall between one or more lattice-extending hoops 134. In various embodiments, the hoops 134 extend around the circumference of the sidewall and provide additional structural integrity to the device. Additionally, as described further below, in various embodiments, the hoops 134 isolate or separate different portions of the sidewall from one another, thereby allowing for the use of different lattice designs or arrangements of the lattice sections within the sidewall. As shown in FIGS. 1A-1B, the plurality of lattice sections includes seven lattice sections 130 occupying 90% or more of the total area of ​​the sidewalls 126A, 126B. However, in various embodiments, the sidewalls 126A, 126B can include a fewer or greater number of lattice sections and can occupy a greater or lesser percentage of the total area of ​​the sidewalls 126A, 126B. For example, in various embodiments, the sidewalls 126A, 126B may include a single lattice section that occupies about 100% of the total area of ​​the sidewall. In certain embodiments, the multiple lattice sections may include two or more lattice sections, each occupying 10%-50% of the total area of ​​the sidewall. In certain embodiments, the sidewalls 126A, 126B may include several smaller individual lattice sections that together make up only about 33% of the total area of ​​the sidewalls 126A, 126B. In various embodiments, the vibration control device may have two or more lattice sections that may be adjacent or non-adjacent on the sidewall. For example, in certain embodiments, a lattice section may be separated from another lattice section by a solid / non-lattice section of the sidewall. In various embodiments, the total area occupied by the lattice sections is between 5%-100% of the total area of ​​the sidewall. As will be further described below, in various embodiments, the lattice sections may be configured using a variety of different lattice designs to tune / control the natural frequency based on the vibration control / structural integrity requirements of the device. In such an embodiment, the multiple grid patterns may share the same pattern or may have different patterns.

[0037] For example, referring to Figures 3A-3F, various embodiments of cylindrical vibration control devices according to one or more embodiments of the present disclosure are shown. The devices 300A-300F include an upper support structure 304, a lower support structure 308, and cylindrical lattice sidewalls 310A-310F connecting the upper support structure 304 and the lower support structure 308 and defining a cylindrical structure configured to support / displace a structural load between a vibration source and a supported load. Thus, in various embodiments, the upper and lower support structures 304, 308 can be positioned between the load and the vibration source such that the lattice sidewalls provide structural support to maintain separation while providing vibration damping to reduce transmission of vibrations through the device as previously described. However, Figures 3A-3F show vibration control devices 300A-300F having various different configurations of lattice design for the sidewalls of the vibration control device. In various embodiments, the lattice design changes the isolation / damping properties of the device. For example, in certain embodiments, a particular lattice design can shift the natural frequency of an attached load as well as control the device to damp vibrations in a particular manner to keep the attached load within acceptable vibration thresholds throughout use. Figures 3A-3F show various configurations of lattice sidewalls, with each sidewall exhibiting a different vibration control profile from the others. In various embodiments, an appropriate lattice sidewall configuration can be selected or used based on the vibration control requirements of the load.

[0038] For example, with reference to the table below, the various embodiments of Figures 3A-3F exhibit different natural frequencies. As explained further below, the configuration of Figure 3A can be referred to as a baseline configuration, and Figures 3B-3F are variations of the baseline configuration of Figure 3A. In this regard, the table below includes lock and bounce ratios that indicate the difference between each embodiment in natural resonant frequency when compared to the baseline of Figure 3A.

[0039] [Table 1]

[0040] In this manner, an existing payload support system for a space launch vehicle may be easily and quickly modified to include appropriate vibration damping characteristics by replacing one or more standard components with an embodiment of the present disclosure configured with lattice sidewalls for vibration damping functionality. For example, in various embodiments, the apparatus of Figures 3A-3F may be used in place of existing structural components within a rocket to adapt the rocket for vibration damping to protect the supported load. In this manner, various embodiments may allow for the reduction or even elimination of separate vibration control devices within a spacecraft, thereby reducing mass and improving payload efficiency.

[0041] With particular reference to FIG. 3A, the lattice sidewall 310A includes a plurality of lattice sections 312, which are defined by a plurality of longitudinally extending hoops 314 that separate / distinguish each of the lattice sections 312 as described above. In FIG. 3A, the lattice designs of each of the plurality of lattice sections 312 are aligned with one another such that the sidewalls form a continuous spiral pattern that extends between the upper support portion 304 and the lower support portion 308. As shown in FIG. 3A, the lattice sections 312 are configured in a lattice pattern having a spiral design, although in various embodiments, the exact type and design of the pattern may vary. In one or more embodiments, the configuration of FIG. 3A may be referred to as a baseline configuration, and FIGS. 3B-3F are variations of the baseline configuration of FIG. 3A.

[0042] For example, Figure 3B shows a variation of the baseline design of Figure 3A, where the lattice sidewall 310B includes two lattice sections 312 that are rotated about a central axis relative to the other lattice sections 316. Thus, the plurality of lattice sections includes a first and second lattice section 316 having a first lattice pattern and a second lattice section 312 having a second lattice pattern. Specifically, in Figure 3B, the top two lattice sections 316 are rotated such that the spiral lattice of the top two sections 316 is radially offset from the lattice section 312, and the top and bottom sections 316, 312 join at the midspan of a vertically extending spiral.

[0043] FIG 3C shows a variation of the baseline design of FIG 3A, where a lattice sidewall 310C includes multiple lattice sections 318 that are each rotated about a central axis relative to an adjacent lattice section 318 such that each lattice section 318 includes a spiral lattice that falls midway through the spiral of the adjacent lattice section. FIG 3D shows a variation of the baseline design of FIG 3A, where a lattice sidewall 310D includes lattice sections 320 that are each rotated a small angle row-by-row relative to an adjacent lattice section 320. Specifically, the lattice sections 320 are rotated such that the spiral design of the sections 320 is rotated a small angle, but not enough that the lattice sections fall midway through the spiral of the adjacent lattice section 320.

[0044] FIG. 3E shows a variation of the baseline design of FIG. 3A, where the lattice sidewall 310E includes only three lattice portions 324, 326, 328. In various embodiments, hoops 314 can be added or removed as needed to adjust the number of defined lattice portions. Thus, with the two central hoops removed, the sidewall 310E includes only three lattice portions, including, for example, the first and second lattice portions 324, 326, each occupying about 20% of the total area of ​​the sidewall 310E, and the third lattice portion 328, occupying about 60% of the total area of ​​the sidewall. FIG. 3F shows a variation of the baseline design of FIG. 3A, where the lattice sidewall 310F includes two lattice portions 334, which include a lattice having a different lattice structure thickness than the remaining lattice portion 330. Specifically, the lattice portion 334 has a thicker lattice structure compared to the lattice structure of the lattice portion 330. Thus, in various embodiments, the lattice design of the sidewalls can include portions of variable thickness or portions having different types of materials, for example, in certain embodiments, some or all of the lattice portions can be composed of different types of materials and / or have different thicknesses.

[0045] Referring to FIG. 4, a prior art spacecraft system 400 is shown. In FIG. 4, the system 400 includes a load 402 and a payload interface system 408. In various embodiments, the payload interface system 408 includes various components including a payload cone or interface cone 410 with one or more connected damping elements 412 that are configured to attach to and support the load 402 for launch. As described above, the payload interface system 408 is a full spacecraft vibration isolation system configured to reduce vibrations imparted to the load 402. Thus, the payload system 408 is designed to reduce the risk of damage to the spacecraft 400 or its equipment prior to entering orbit. To get through this stage, the payload interface system 408 provides support structures such as the payload cone 410 and damping elements 408 to damp and / or isolate the load 402 from vibrations 415 originating from the load. The payload interface thus provides a structural element for supporting the load 402, and the damping element 412 includes various isolator components, such as springs, damping materials, or the like, for inhibiting the transmission of vibrations from the spacecraft to the load. The damping element 412 can thus be used to reduce the vibration amplitude 416 transmitted to the load 402 with respect to the source vibration 415.

[0046] Depending on the weight of the load 402, the isolators themselves need to be appropriately selected and sized based on the natural frequency of the load 402 being supported. Additionally, mounting hardware is required to secure each isolator. This includes fasteners, washers, and supports as needed. Additionally, heat sink brackets or other thermal management systems may be required along with various ground straps.

[0047] 5A-5B, various embodiments of a total spacecraft isolation system 500 including a vibration control device 504 are shown in accordance with one or more embodiments of the present disclosure. In particular, FIG. 5A shows a cross-sectional plan view of the vibration control device as part of a total spacecraft isolation system 501 with a load 502 attached, and FIG. 5B shows a partial perspective view of the vibration control device 504.

[0048] In various embodiments, the vibration control device 504 is the same as or substantially similar to the vibration control device 100B described above with reference to FIG. 1B. For example, in one or more embodiments, the vibration control device 504 includes a frame structure including a first support structure 520 and a second support structure 522 attached to the vibration source 508 and the supported load 502, respectively. In various embodiments, the first and second support structures 520, 522 are generally solid portions of the device configured to be attached to the load 502 and the vibration source 508. Thus, in various embodiments, the support structures may also be referred to as the upper or lower portions of the device 504.

[0049] In various embodiments, the device 504 includes a lattice-like sidewall 510 connecting the first and second support structures 520, 522. In such embodiments, the sidewall 510 is configured to support a structural load against the first and second support structures 520, 522. In various embodiments, the lattice-like portion 530 of the sidewall 510 is configured to damp the transmission of vibrations between the first and second support structures 520, 522 by blocking the transmission of vibrations 415 through the sidewall 510. For example, in one or more embodiments, the lattice design changes the isolation / damping properties of the device 504 such that the device naturally has vibration damping properties without the use of a separate damping device such as a spring or the like as shown in FIG. 4. In certain embodiments, the device 504 can shift the natural frequency of the attached load 502 as well as control the device to damp vibrations in a specific manner to keep the attached load within acceptable vibration thresholds.

[0050] 6A-6B, additional embodiments of a total spacecraft isolation system 600A, 600B including one or more vibration control devices 504, 606 are shown according to embodiments of the present disclosure. In various embodiments, the vibration control device may be configured as various parts of the spacecraft isolation system in addition to or instead of the payload cone vibration control device 504 shown in FIGS. 5A-5B. For example, as shown in FIG. 6A, the cylindrical support 420 of FIG. 4, which is normally used only for structural support of the load 402, is replaced with a vibration control device 606 that supports the load 602. In various embodiments, the vibration control device 606 is substantially similar to the device 100A described above with reference to FIG. 1A. Thus, the device 606 includes a lattice-like sidewall 610 having a lattice-like portion configured to damp transmission of vibrations by blocking transmission of vibrations through the sidewall 610. For example, in one or more embodiments, the lattice design changes the isolation / damping properties of the device 606 such that the device naturally has vibration damping properties without the use of a separate damping device such as a spring or the like.

[0051] 6B, in various embodiments, one or more additional components of the spacecraft can be replaced with structurally equivalent vibration control devices such that the spacecraft includes multiple vibration control devices 606, 504, both of which function together to dampen vibration transmission from a source to an attached load. In such embodiments, by further replacing existing components with vibration control devices, the combination of multiple isolators can further shift the natural frequency of the attached load as well as control the devices to dampen vibrations in a specific manner to keep the attached load within acceptable vibration thresholds.

[0052] Referring to FIG. 7A, a method 700 of installing a vibration control device is shown according to one or more embodiments of the present disclosure. In one or more embodiments, the method 700 includes, in operation 704, determining vibration damping requirements for a potential load. For example, with further reference to FIG. 7B, a graph 700 is shown illustrating vibration amplitudes 726 that a load can undergo over a range of vibration frequencies 728. Specifically, the graph 700 illustrates a maximum vibration threshold 704 for the vibration amplitude 726 and range of vibration frequencies 728 that the load can undergo without damaging the load. As seen in the graph 700, the load and vibration threshold 704 have a variety of different allowable amplitudes 726 that depend on the vibration frequency. For example, as seen in FIG. 7B, the load undergoes higher vibration amplitudes at lower frequencies, but as the frequency increases, the allowable amplitude threshold decreases rapidly.

[0053] In various embodiments, the load experiences a baseline amplitude across the frequency range, shown as baseline line 730, which indicates the vibration amplitude experienced by the load when attached to a standard payload cone. As seen in FIG. 7B, the load has a peak amplitude at point 732 that exceeds the vibration threshold 704 due to the baseline natural or resonant frequency of the load and the attached payload cone components. Thus, the vibration damping action in various embodiments functions to shift the natural resonant frequency of the attached load and / or reduce the magnitude of the amplitude peak such that the vibration amplitude experienced by the load is below the vibration threshold 704 throughout the range of frequencies 728. Specifically, in certain embodiments, the peak amplitude that occurs at the natural or resonant frequency is shifted to where the load has a maximum capacity to experience vibration. For example, in FIG. 7B, the natural frequency may be shifted to occur at a lower frequency than threshold 704 has a maximum capacity for vibration amplitude.

[0054] In one or more embodiments, the method 700 includes, in operation 708, obtaining a lattice vibration control device for a potential load based on vibration damping requirements. The lattice vibration control device can be manufactured using various manufacturing processes or methods. For example, in certain embodiments, the device can be manufactured using wet filament winding technology. In some embodiments, the device can be manufactured using printed tooling technology such as Ultem™ printed tooling. In such embodiments, the printed tooling manufacturing and design is modular, often with interlocking sectors that can be swapped or combined for various new but similar designs. Thus, in various embodiments, the printed tooling manufacturing allows the device to be rapidly manufactured / modified to produce a lattice design that meets the vibration damping requirements of a particular project by modifying the lattice design as needed. Additionally, in various embodiments, the material used for printing has a relatively high coefficient of thermal expansion, which acts as a secondary force (other than vacuum) to assist in ply compaction. High growth tooling also helps eliminate wrinkles.

[0055] In one or more embodiments, the device can be manufactured using a hand layup process. In such an embodiment, the hand layup technique, which may seem cumbersome and laborious, allows for simplified, less robust tooling because it does not need to be designed with an adapter to interface with the winder and also eliminates the stresses induced by the weight of the winder or tool in the horizontal configuration. Hand layup allows any local features to be easily designed into the tooling. This includes various lattices or asymmetric rib patterns. Hand layup can also support 0 degree (axial) ribs and does not require additional helical ribs to jump between hoop bands during successive strand windings.

[0056] In various embodiments, the device may be constructed from a variety of materials, such as steel, aluminum, polymers, composites, or the like. In one or more embodiments, the device may be constructed from a combination of materials. For example, in certain embodiments, the lattice portion is constructed from a first material, such as a composite material, and the support portion is constructed from a second material.

[0057] In various embodiments, the materials used can have inherent damping properties such that the use of the material provides additional damping to the device. In such embodiments, the additional damping can reduce peak vibration amplitudes. For example, in one or more embodiments, a carbon nanotube (CNT) composite material having damping properties is used for at least the lattice portion. In such embodiments, the CNT material can be used for all primary and secondary structures to essentially inhibit the dynamic environment. In various embodiments, the CNT material can be constructed using a laminar bonding process to mold / form a lattice-like structure from multiple bonded sheets of CNT material.

[0058] In such embodiments, the CNT material may include one or more of X55 acetone condensate, 112 polymer containing X55 in TC 275, Nanocomp® CNT material processed using acetone to condense the tubes into a coherent sheet, spray-form X55 / TC420, X55 sheet spray-coated with TC420 epoxy and cured, and N12 NanoStitch. In one or more embodiments, the interlaminar bonds may be reinforced by filling resin-rich zones between the tape layers. In such embodiments, the reinforcing material may include chopped CNT material dispersed in resin at a ratio of 2% and filmed on a pre-impregnated IM / 7 fabric. In such embodiments, the resin material may include NanoComp® TC275 resin. In further embodiments, the reinforcing material can include high growth rate (HGR)-pure CNT nonwoven fabrics manufactured at a high growth rate, and low growth rate (LGR)-pure CNT nonwoven fabrics manufactured at a low growth rate.

[0059] In various embodiments, viscous damping in lattice devices is provided by interlaminar bonding materials. Damping using layers of viscoelastic material constrained or sandwiched between metal or composite layers can provide 2% or more damping. Damping with viscoelastic materials requires complex stiffness models. In such embodiments, this form of damping can be modeled as a constant multiple of velocity using NASTRAN or other suitable modeling process.

[0060] In one or more embodiments, method 700 includes testing the vibration damping characteristics at operation 712. In various embodiments, the resulting device may be tested utilizing a modal testing process. If the damping performance is within the vibration damping requirements, the method may end at decision point 716 as the vibration control device is sufficient to meet the requirements of the load. If the damping performance is outside the vibration damping requirements, at decision point 716, method 700 proceeds to operation 720, where the method includes adjusting the vibration damping and resuming the testing operation at 712. In such embodiments, the process may be repeated and the vibration control device design may be iterated until an adjusted vibration amplitude curve 734 is determined that is within the vibration threshold 704.

[0061] For example, as discussed above, at least in FIGS. 3A-3B, depending on the design of the lattice structure, the various disclosed vibration control devices exhibit vibration isolation performance with known natural frequencies that differ from other designs. In this manner, existing payload support systems for spacecraft launch vehicles can be easily and quickly modified to include appropriate vibration damping characteristics by replacing one or more standard components with embodiments of the present disclosure configured with lattice sidewalls for appropriate vibration damping functions. For example, in various embodiments, the devices of FIGS. 3A-3F can be used in place of existing structural components in a rocket to adapt the rocket to vibration damping for protecting the supported load. Furthermore, in various embodiments, if it is found that a first lattice design does not exhibit vibration damping within the threshold, additional changes or modifications can be made to the design to shift the natural frequency and / or add additional damping material to bring the damping curve within the threshold of the device. In this manner, various embodiments can allow for the reduction or even elimination of separate vibration control devices in a spacecraft, thereby reducing mass and improving payload efficiency.

[0062] In various embodiments, the method 700 includes, at step 724, installing a vibration control device. In various embodiments, due to the nature of the lattice structure, the embodiments can function as a drop-in replacement for an existing structure or part in a system, providing vibration damping / control while also maintaining the same or similar structural strength as the replaced structure / part. Thus, various embodiments allow for "plug and play" use in existing / legacy systems without requiring redesign or significant modification. For example, in various embodiments, an existing legacy part may simply be removed and replaced by an embodiment of the present disclosure that maintains similar shape, size, and structural characteristics to support a load, but includes inherent vibration damping / isolation properties as a result of the lattice structure / lattice design, as opposed to the replaced part.

[0063] As used herein, the terms vibration control, vibration isolation, vibration damping, vibration attenuation, etc. are used generally to refer to the concept of vibration control / reduction. Thus, the terms isolator, damping, damping, etc. are not intended to be limited to any particular design / technology unless otherwise indicated.

[0064] The description of various embodiments of the present disclosure is presented for illustrative purposes, but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to explain the principles of the embodiments, practical applications or technical improvements to the technology found in the market, or to enable other skilled in the art to understand the embodiments disclosed herein.

Claims

1. 1. A vibration control system for total spacecraft vibration isolation, comprising: a payload interface cone for connection between a spacecraft vibration source and a load, said payload interface cone comprising: a first support structure, a second support structure, and a sidewall extending between the first support structure and the second support structure and defining a frusto-conical body of the payload interface cone, the sidewall configured to structurally support the load relative to the second support structure; the sidewall includes one or more lattice sections occupying at least a portion of a total area of ​​the sidewall, the lattice sections configured to damp transmission of vibrations through the sidewall between the first support structure and the second support structure to reduce vibration transmission from the vibration sources and the loads on the spacecraft; the frusto-conical body of the payload interface cone is substantially identical to a spacecraft payload interface cone without one or more lattice sections such that the payload interface cone is a drop-in replacement part; The system does not include a separate damping device.

2. 2. The system of claim 1, wherein the one or more grid portions are a plurality of grid portions, each of the plurality of grid portions being defined by one or more latitudinal extending hoops extending around a circumference of the sidewall.

3. The system of claim 2 , wherein the plurality of grid sections includes a first grid section having a first grid pattern and a second grid section having a second grid pattern.

4. 4. The system of claim 3, wherein the first and second lattice patterns are selected from a group of lattice patterns including a spiral lattice, a hexagonal lattice, a P-hexagonal lattice, a Bravais lattice, a cubic Bravais lattice, a square lattice, a triclinic lattice, a monoclinic lattice, and an orthorhombic lattice.

5. 4. The system of claim 3, wherein the first and second grid patterns are spiral grids, the first grid pattern rotated about a central axis relative to the second grid pattern such that the first and second grid patterns are rotationally offset from one another.

6. 3. The system of claim 2, wherein the plurality of lattice sections includes five sections, and the upper two sections of the side wall are spiral lattices and are rotated around a central axis relative to each other so that the individual spiral lattices connect at the middle of the spiral.

7. 4. The system of claim 3, wherein the plurality of lattice sections includes five sections, each section within the sidewall being a spiral lattice and rotated about a central axis relative to each other such that each spiral lattice connects to an adjacent lattice section midway through the spiral.

8. 3. The system of claim 2, wherein the plurality of grid portions includes three portions including first and second portions each occupying approximately 20% of the total area of ​​the sidewall, and a third portion occupying approximately 60% of the total area of ​​the sidewall.

9. The system of claim 1 , wherein the one or more lattice portions occupy 90% or more of a total area of ​​the sidewall.

10. The system of claim 1 , wherein the one or more grating portions occupy between 5% and 90% of a total area of ​​the sidewall.

11. 2. The system of claim 1, wherein the one or more lattice portions include two or more lattice portions, each of the two or more lattice portions occupying between 10% and 50% of a total area of ​​the sidewall.

12. The system of claim 1 , wherein the sidewall includes one or more non-lattice portions.

13. The system of claim 1 , wherein the one or more lattice portions are adjacent within the sidewall.

14. The system of claim 1 , wherein the one or more grid portions are separated by non-grid portions.

15. 10. The system of claim 1, wherein the one or more lattice portions within the sidewall are at least partially constructed from a carbon nanotube (hereinafter CNT) composite material having vibration damping properties.

16. 16. The system of claim 15, wherein the CNT lattice portion is formed into a lattice-like structure from multiple bonded sheets of CNT material using a layer-by-layer bonding process.

17. 17. The system of claim 16, wherein the CNT material comprises X55 acetone.

18. 1. A vibration control system comprising: a vibration isolation component for structurally isolating the load from a vibration source, the vibration isolation component comprising: a first support structure, a second support structure, and a sidewall extending between the first support structure and the second support structure and defining a body of the vibration isolation component, the sidewall configured to structurally support the load relative to the second support structure; the sidewall includes one or more lattice sections occupying at least a portion of a total area of ​​the sidewall, the lattice sections configured to damp transmission of vibrations through the sidewall between the first support structure and the second support structure to reduce vibration transmission from the vibration sources and the loads on the spacecraft; the body of the vibration isolation component is substantially the same as the spacecraft component without one or more lattice portions such that the vibration isolation component is a drop-in replacement for the spacecraft component; the one or more lattice portions within the sidewall are constructed at least in part from a carbon nanotube (CNT) composite material having vibration damping properties; The system does not include a separate damping device, vibration control system.

19. The vibration control system of claim 18 , wherein the sidewall is cylindrical.

20. The vibration control system of claim 18 , wherein the sidewall is a bulkhead.

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