Patent Application
20180370613
Composite materials, such as carbon fiber reinforced polymer materials, typically are used in applications in which properties of such materials may be advantageous. For example, such materials are strong but lightweight, resulting in their widespread use in fields such as aviation or other lightweight air, ground, or waterborne vehicles.
Typically, composite materials are rigid, which can be an advantage in certain respects but may be a limitation in others. For example, in aviation and other applications, the rigidity of composite materials may make them unsuitable for use in applications that may require a more flexible material and/or one that may be more durable over many cycles of being bent or flexed.
Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings.
The invention can be implemented in numerous ways, including as a process; an apparatus; a system; a composition of matter; a computer program product embodied on a computer readable storage medium; and/or a processor, such as a processor configured to execute instructions stored on and/or provided by a memory coupled to the processor. In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the invention. Unless stated otherwise, a component such as a processor or a memory described as being configured to perform a task may be implemented as a general component that is temporarily configured to perform the task at a given time or a specific component that is manufactured to perform the task. As used herein, the term ‘processor’ refers to one or more devices, circuits, and/or processing cores configured to process data, such as computer program instructions.
A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.
A composite structure with an integrated hinge comprising one or more layers of high strength synthetic fiber fabric, such as Kevlar® or another aramid material or material with similar properties, is disclosed. In various embodiments, one or more layers of high strength synthetic fiber fabric, such as Kevlar® or another aramid material or material with similar properties, are interleaved with other composite layers in an overlapping manner that results in a composite structure in which a portion of the high strength synthetic fiber fabric is present in a region that joins a first relatively rigid composite component/structure to a second relatively rigid composite component in a flexibly bendable manner. For example, in one application, a composite structure with an integrated hinge as disclosed herein includes an aircraft component, such as a wing, tail, or other aerodynamic structure, in which an integrated hinge as disclosed herein joins an access flap to the aircraft component, enabling access to be gained to structures located under the flap, e.g., by lifting the flap and thereby bending the hinge.
In the example shown, aerodynamic control structure 104 is positioned (e.g., moved up, down, and/or back to a neutral position) via a mechanical linkage 106. The mechanical linkage 106 is driven, in this example, by structures to which access (e.g., for repair) is provided via a hinged flap 108. Specifically, hinged flap 108 provides access to a void 110 in which a servo motor and/or associated power supply and/or control circuits and/or wires or other connectors are located. As shown in the lowermost drawing of
In various embodiments, hinged flap 108 is attached integrally with the composite structure of airfoil 102 by a hinge structure comprising one or more layers of Kevlar® or other aramid or other polymer fabric material having high strength (e.g., tensile strength) and greater flexibility as compared to the composite structure of airfoil 102 itself. For example, in some embodiments, hinged flap 108 may comprise a flap made of the same or similar composition as the composite structure of airfoil 102, and a hinge material comprising one or more layer interleaved with adjacent layers of the composite material comprising airfoil 102. The resulting structure(s) in some embodiments may be compressed (e.g., by vacuum, a press, or other means) and cured to form a combined structure comprising the composite structure of airfoil 102 (e.g., multi-layer carbon fiber reinforced polymer composite), a hinge portion (e.g., one or more layers of Kevlar®), and a flap portion comprising a segment of rigid composite material coupled to the composite structure of airfoil 102 by the hinge portion.
While
In various embodiments, the rightmost end of the composite structure comprising layers 212, 214, and 216 is free, as in the free (trailing) end of hinged flap 108 of
In some embodiments, the hinge material 220, 222 comprises two layers of prepreg Kevlar, e.g., 0.004 in thick layers, both oriented in the 0°/90° direction. In some embodiments, hinge material 220 and hinge material 222 overlap by a minimum of ½ inch (total) with the ends not superimposed on top of one another, e.g., in some embodiments they are staggered by ¼ inch or so on each side as shown.
Note that while the term “primary” and “secondary” are sometimes used herein to refer to composite structured joined by an integrated hinge as disclosed herein, in various embodiments any “first” and “second” composite structures may be connected by an integrated hinge as disclosed herein.
In nearly adjacent regions of the primary structure, on the one hand, and the access flap or other secondary structure, on the other, layers of Kevlar® or other flexible hinged materials are interleaved with adjacent layers of prepreg (or other rigid composite precursor material) (304). For example, segments of Kevlar® may be laid across opposite edges of the lower layer stack of the primary and secondary composite structures, and alternating layers in between, followed by one or more upper layers of prepreg.
The laminate stacks, including the interleaved hinge materials, are cured (306). For example, pressure may be applied to compress the stacked layers of material, and the combined mass heated to cure the resin in the prepreg, resulting in a composite structure comprising an integrated flexible hinged, the hinge comprising hinge material interleaved with and bonded at each end with alternating layers of composite material.
In various embodiments, a composite structure with an integrated hinge, as disclosed herein, may be used to provide a hinged access flap or other structure having a durable, flexible hinged attachment to and integration with a primary composite structure. In various embodiments, integrating the hinge material into the composite layer stack, as disclosed herein, may enable the hinge to be integrated with the composite structure in a secure manner without requiring additional adhesives or mounting hardware. The resulting structure may have minimal drag and lower complexity and/or failure modes as compared to other solutions to provide an access flap or other hinged connection between composite parts.
Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed embodiments are illustrative and not restrictive.
