Lightweight structural component in particular for aircraft and method for its production

Abstract

Lightweight structural component including at least one panel and at least one stiffening element oriented one of lengthwise and crosswise. The at least one stiffening element includes two side pieces. Each of the two side pieces is at least partially connected to the panel in a material-locking manner. The two side pieces are connected to the panel at two separate joint zones. A method of producing the lightweight structural component includes milling the at least one panel to form at least one thickened region and joining the two side pieces to the at least one panel at the two separate joint zones. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation application of parent U.S. patent application Ser. No. 10 / 757,419 filed on Jan. 15, 2004, the disclosure of which is expressly incorporated by reference herein in its entirety. The present application also claims priority under 35 U.S.C. §119 of German Patent Application No. 103 01 445.4, filed on Jan. 16, 2003, the disclosure of which is expressly incorporated by reference herein in its entirety.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to the design and production of lightweight structural components. Objects in which its application is expedient and possible are all large-volume lightweight structures in which an essential part of the bearing pressure occurs as area load via skin sheets and which are provided with stiffening elements for load distribution, load diversion, reduction of deflection or prevention of denting or buckling. Typically such cas...

Examples

example 1

[0124]The lower fuselage of an aircraft is to be embodied with a higher dent resistance and an improved stiffness. At the same time, production costs and weight are to be reduced. To this end, a riveted construction is replaced by a laser beam-welded construction in a configuration according to the invention, as shown in FIG. 1 for the stringer / panel variant.

[0125]The panel 1 includes a panel base 11. A stringer 2 normally embodied with a stringer head 12 and stringer bar 4 features on its side facing the skin sheet 1 two side pieces 5, 6. The lower sides of the two side pieces 5, 6 extend from the stringer foot 3 and run horizontally. In this way, they rest on a level panel base 11. Both side pieces 5, 6 are connected in a material-locking and / or fixedly secured manner to the panel base 11 with two separate joint zones 7, 8. The center-lines of the joints 7, 8 can form an angle of respectively γ=approximately 20° to the surface of the panel base 11 (see FIG. 2). The joint zones 7, ...

example 2

[0135]Further advantages of the invention are to be explained on the basis of a further developed embodiment that leads to a clearly improved damage tolerance behavior. It is particularly suitable for the side fuselage area but also for the upper fuselage area, i.e., for transverse stress and / or tensile stress.

[0136]One preferred geometric embodiment is shown in FIG. 2. In addition to the features specified in exemplary embodiment 1, the panel 1 also features a panel stiffening base 13. The two outer sides 16 of the panel stiffening base 13 are inclined at an angle of approx. a / 2 and are thus adapted to the inner sides of the side pieces 5, 6 that are also inclined at an angle of approx. a / 2 from the symmetric line (i.e., the center line running through stringer bar 4). The joint surfaces 9, 10 of the base 13 and of the two side pieces 5, 6 are inclined at an angle β≧approx. α / 2 with respect to the surface of the panel 1. With a weld seam angle γ≈β, the weld seam thus lies generally...

example 3

[0159]Another variant for improving the damage tolerance of welded panel / stringer connections is explained in FIGS. 10 and 11.

[0160]High tensile stresses prevail in the upper shell area along the weld seams in a stringer / skin connection. They can be reduced by stress relief elements embedded in the panel base parallel to the stringer. In one preferred embodiment they comprise wires of high-strength steel, titanium or Ni materials. Their positive effect regarding damage tolerance is due to two effects: firstly, due to their higher modulus of elasticity they put up a higher resistance to an elongation along the wire axis than the skin material surrounding them or the weld seam, so they relieve the stress on their surroundings. The crack growth rate is thus reduced when the crack approaches the stress relief element and thus the weld seam. Secondly, the residual strength is improved, because the stress relief element still remains intact after the crack has crossed the surroundings of ...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a continuation application of parent U.S. patent application Ser. No. 10 / 757,419 filed on Jan. 15, 2004, the disclosure of which is expressly incorporated by reference herein in its entirety. The present application also claims priority under 35 U.S.C. §119 of German Patent Application No. 103 01 445.4, filed on Jan. 16, 2003, the disclosure of which is expressly incorporated by reference herein in its entirety.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to the design and production of lightweight structural components. Objects in which its application is expedient and possible are all large-volume lightweight structures in which an essential part of the bearing pressure occurs as area load via skin sheets and which are provided with stiffening elements for load distribution, load diversion, reduction of deflection or prevention of denting or buckling. Typically such cas...

Examples

example 1

[0124]The lower fuselage of an aircraft is to be embodied with a higher dent resistance and an improved stiffness. At the same time, production costs and weight are to be reduced. To this end, a riveted construction is replaced by a laser beam-welded construction in a configuration according to the invention, as shown in FIG. 1 for the stringer / panel variant.

[0125]The panel 1 includes a panel base 11. A stringer 2 normally embodied with a stringer head 12 and stringer bar 4 features on its side facing the skin sheet 1 two side pieces 5, 6. The lower sides of the two side pieces 5, 6 extend from the stringer foot 3 and run horizontally. In this way, they rest on a level panel base 11. Both side pieces 5, 6 are connected in a material-locking and / or fixedly secured manner to the panel base 11 with two separate joint zones 7, 8. The center-lines of the joints 7, 8 can form an angle of respectively γ=approximately 20° to the surface of the panel base 11 (see FIG. 2). The joint zones 7, ...

example 2

[0135]Further advantages of the invention are to be explained on the basis of a further developed embodiment that leads to a clearly improved damage tolerance behavior. It is particularly suitable for the side fuselage area but also for the upper fuselage area, i.e., for transverse stress and / or tensile stress.

[0136]One preferred geometric embodiment is shown in FIG. 2. In addition to the features specified in exemplary embodiment 1, the panel 1 also features a panel stiffening base 13. The two outer sides 16 of the panel stiffening base 13 are inclined at an angle of approx. a / 2 and are thus adapted to the inner sides of the side pieces 5, 6 that are also inclined at an angle of approx. a / 2 from the symmetric line (i.e., the center line running through stringer bar 4). The joint surfaces 9, 10 of the base 13 and of the two side pieces 5, 6 are inclined at an angle β≧approx. α / 2 with respect to the surface of the panel 1. With a weld seam angle γ≈β, the weld seam thus lies generally...

example 3

[0159]Another variant for improving the damage tolerance of welded panel / stringer connections is explained in FIGS. 10 and 11.

[0160]High tensile stresses prevail in the upper shell area along the weld seams in a stringer / skin connection. They can be reduced by stress relief elements embedded in the panel base parallel to the stringer. In one preferred embodiment they comprise wires of high-strength steel, titanium or Ni materials. Their positive effect regarding damage tolerance is due to two effects: firstly, due to their higher modulus of elasticity they put up a higher resistance to an elongation along the wire axis than the skin material surrounding them or the weld seam, so they relieve the stress on their surroundings. The crack growth rate is thus reduced when the crack approaches the stress relief element and thus the weld seam. Secondly, the residual strength is improved, because the stress relief element still remains intact after the crack has crossed the surroundings of ...

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