The area of application for the invention extends primarily to aircraft construction. In particular commercial aircraft are fabricated using a shell type of construction with respect to the large-volume fuselages, wherein an internal reinforcement structure supports a shell component, which as the outer skin comprises the outside surface of the fuselage. The internal reinforcement structure usually consists of longitudinally running stringers and frames running transversely and roughly annularly thereto, which are joined to the shell component on the inside. In modern production technologies, at least the stringers are most often bonded to the shell component during its fabrication, so that separate attachment means, such as rivets, need not be used. Aside from T-stringers, so-called omega stringers are used for this purpose, and are here also referred to as omega profile components. Within the framework of the present invention, omega profile components are understood as cross sectional forms of profile components, which exhibit an open profile cross section, and together with the shell component yield a closed profile. For example, the profile cross sections are here symmetrical, and exhibit two nonparallel, opposing flank sides extending away from the shell component.
By comparison to the T-stringers, such profile cross sections have a greater area moment of inertia, so that they impart a high stability in particular to an aircraft structure. In a special embodiment, an omega profile component involves a reinforcement profile made out of metal or plastic with a roughly hat-shaped, symmetrical cross section. In addition to aircraft construction, these components can also be used in conjunction with other large-scale shell components from automotive engineering, ship engineering and the like. The solution according to the invention can also be applied thereto.
Known from DE 103 31 358 A1 is a method for fabricating a structural component of an aircraft fuselage, in which the stringers are bonded to the shell component in a special manufacturing process. The outer surfaces of the mold carrier with the modular profiles imbedded in annular channels are here covered with a loosely overlying film. The hollow space formed by the gaps is exposed to a vacuum in such a way as to aspirate the film over the annular channel and slits of the modular profiles. After a sufficient vacuum has been achieved, the film roller is coupled with the vacuum skin roller in such a way that the film is wound, and the vacuum skin is unwound on the outer surfaces of the modular profiles, and drawn into the profile grooves of the depressions in a dimensionally accurate manner. Stringers provided with support elements are subsequently inserted into the profile grooves covered by the vacuum skin. All fiber composite skin layers are then placed on the vacuum skin-covered outer surfaces of the modular profiles and the stringers. Finally, an optimal quantity of sealing compound is applied to the outer skin layer. A structural shell is precisely fitted onto the sealing compound, so as to compact the sealing compound in such a way as to yield a vacuum-tight seal between the vacuum skin and structural shell. After the prescribed process vacuum has been reached, the cavity between the vacuum skin and structural shell, the vacuum is also turned off, and the hollow space is opened toward the atmosphere. The structural shell can thereupon be lifted and rotated by 180°, so as to subject the latter to an injection and curing process. The finished structural shell comprised of a shell component can subsequently be removed from the mold with stringers.
Before curing and/or after fabricating such a structural component, the stringer position relative to the shell component must be measured, in order to run a quality control for dimensional accuracy. This had previously been accomplished in complicated manual measurements by means of a photometric procedure, in which markings must first be provided to the stringer face and shell component, which are subsequently acquired by a picture camera and evaluated through image processing.
However, the present invention can also be used independently of the so-called AutoVac process described above. The basic application involves a shell component with omega profile components, regardless of the method used in their fabrication.
USPTO Backgrounds
USPTO Backgrounds