Patent Application
20140315040
Exemplary embodiments of the invention relate to structural components and, more particularly, to a stiffener configured for use with such structural components, the stiffener being formed by an additive metal fabrication process.
As illustrated in
In applications where weight is critical, such as aircrafts or rotary-wing aircrafts for example, inclusion of such structural stiffeners significantly increases the weight of an assembly. In addition, the structural stiffeners also increase space required, the time to assemble, and the overall manufacturing cost of an assembly.
According to one embodiment of the invention, a method of integrally forming at least one stiffener onto a sheet metal component configured to carry a load is provided including generating a stereolithography file. The stereolithography file includes a surface geometry of the at least one stiffener extending from a surface of the sheet-metal component. The surface geometry of the stereolithography file is sliced into a plurality of thin strips. The plurality of thin strips is substantially parallel to the surface of the sheet metal component. Energy from an energy source is applied to a powdered material such that the powdered material fuses to form the plurality of thin strips. One of the plurality of thin strips is integrally formed with the surface of the sheet-metal component. Each of the plurality of thin strips is integrally formed with an adjacent thin strip to create at least one stiffener.
According to another embodiment of the invention, an assembly is provided including a thin sheet-metal component. At least one stiffener is integrally formed with a first surface of the sheet-metal component through an additive metal fabrication process. The at least one stiffener is configured to enhance a load carrying capability of the sheet-metal component.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
Referring now to
At least one stiffener 40 is arranged adjacent a first surface 12 of the sheet-metal component 10, for example adjacent the portion of the component 10 configured to experience the greatest stress when a load is applied thereto. In one embodiment, a plurality of stiffeners 40 is arranged on the first surface 12 of the component 10, the plurality of stiffeners 40 being separated from one another by a distance in a first direction. The plurality of stiffeners 40 may be substantially identical or may be distinct. The at least one stiffener 40 may be configured to extend over the entire width of the sheet-metal component 10, or may be configured to extend over only a portion thereof. In embodiments where the width of a stiffener 40 is less than the width of the sheet-metal component 10, the stiffener 40 may be arranged adjacent an edge, such as opposing edges 14 and 16 for example, or alternatively, may be arranged generally centrally about the sheet-metal component 10 (
In one embodiment, the at least one stiffener 40 is generally rectangular in shape and has a substantially constant cross-section over the width of the sheet-metal component 10. However, a stiffener 40 having a cross-section that varies over the width of the sheet-metal component 10 is also within the scope of the invention. In one embodiment, more than one stiffener 40 is arranged across the width of the sheet-metal component 10. The more than one stiffener 40 may be arranged substantially linearly such that a space exists between adjacent stiffeners 40, the space extending in a second direction, perpendicular to the first direction.
Referring again to
In another embodiment, illustrated in
The plurality of stiffeners 40 may be formed integrally with the sheet-metal component 10 through an additive metal fabrication process that applies light energy to a generally powdered material, such as a powered metal, metal alloy, or composite material for example, to form a shape. Exemplary additive metal fabrication processes include, but are not limited to, direct metal laser sintering (DMLS), selective laser sintering (SLS), and electron beam melting (EBM) for example.
Referring now to
In block 106, after the model of the stiffeners 40 has been sliced into a plurality of strips, energy from an energy source is applied to a portion of a powdered material on the first surface of the sheet-metal component. Examples of the energy source include but are not limited to, an electron beam, a laser, or any other suitable light source known to a person having ordinary skill in the art for example. The energy or heat from the energy source locally melts the powdered material such that the powdered material fuses into a plurality of substantially solid parts. Each fused solid part is a generally two-dimensional section representing a thin strip of each of the plurality of stiffeners 40. In embodiments including more than one stiffener 40, a portion of a first stiffener within the first strip may be fabricated, and then a portion of a second stiffener within the first strip may be fabricated. Additional powdered material is arranged on a surface of the fused solid parts in block 108. Similar to block 106, in block 110, energy from the energy source is again applied to the powered material to form an adjacent thin strip of the stiffeners 40. The addition of powered material in block 108 and the application of energy to the powered material in block 110 are generally repeated until each of the plurality of thin strips from the stereolithography file has been fabricated. Because the strips of the at least one stiffener 40 are built sequentially, each thin strip is integrally formed with another adjacent thin strip to form the one or more stiffeners 40. In one embodiment, a protective coating may be applied to the stiffeners 40 and/or the sheet-metal component 10 based on the intended application of the sheet-metal component 10, as illustrated in block 112.
Use of stiffeners 40 integrally formed with the sheet-metal component 10 through an additive metal fabrication process reduces the overall number of parts and complexity of the assembly. As a result, the tooling and hours required to fabricate the sheet-metal component 10 and the stiffeners 40 are significantly reduced. In addition, by selectively applying stiffeners 40 to only the portion of the sheet-metal component that experiences higher loads, the overall weight of the assembly may be reduced.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
