Deutsches Zentrum Fur Luft-und Raumfahrt E.v.

Deutsche Forschungsanstalt Fur Luft-und Raumfahrt E.v.

Matthias Piening

Arno Erk Pabsch

Christof Sigle

Andreas Buter

Hans Peter Monner

In a structural element of high unidirectional rigidity, in which unidirectional fiber strands are completely embedded in sheaths and said sheaths are connected to a shell skin and wherein part of the shell skin is in the form of stringers, there is provided an inner division of the cross-section of the shell skin thereby providing the strength of the fibers and the stiffness of the fibers in a direction perpendicular to the skin plane for every direction of loading.

Structural element of high unidirectional rigidity

In a process for producing large-surface structural elements from fiber-reinforced composite materials by resin transfer moulding, a mold (,) that can be evacuated has a dimensionally stable part (,) and an elastically deformable part (,). The mold (,) has connections for injecting a resin mixture and connections to a pressure sink. A fibrous fabric (,) is set into the mold (,). Elongated pipes having a large supporting surface (,) and a cavity (,) that extends in the longitudinal direction of the pipes above the supporting surface (,) are provided on the surface of the fibrous fabric (,) opposite to the dimensionally stable mold part (,) to inject the resin mixture and to ensure the connection with the pressure sink. The supporting surface (,) of the pipes has a narrow slit (,) which extends substantially over the whole length of the pipes and which is in communication over its whole length with the cavity (,). At least one end of the pipes extends outwards through the edges of the elastically deformable and dimensionally stable mold parts and is linked to the resin supply pipe or to the pressure sink. The mold (,) is evacuated down to an inner pressure of less than 50 hPa.

Apparatus for making components of large area by RTM

In an aerofoil profile with variable profile adaptation and rigid rib structure, the aerofoil profile has a flexible rib structure with rib elements, which are arranged in segments and are articulated to one another in the form of a kinematic chain in order to transmit movement, a skin panel capable of sliding on this and also at least one driving means for moving the flexible rib structure.

Aerofoil profile with variable profile adaptation

An aircraft with supporting wings including wing shells with good shear strength made of fibrous composite materials, particularly fiber-reinforced plastics, having members taking up tensile and compressive forces on the inside of the wing shells. The members have unidirectional fibers extending longitudinally of the wing, and fixing elements which can be joined detachably to fuselage attachments are provided on the members at the root end of the wing. Stringers are constructed on the inside of the wing shells and spaced longitudinally of the shells, their fiber component being formed by a fiber layer joined to the fiber layer of the wing shell. Fiber bundles are arranged between spaced stringers as unidirectional stiffening elements. The fiber bundles are embedded in the synthetic resin matrix of the plane load-bearing structure and extend longitudinally of the supporting wing. Groups of three fiber bundles extending adjacent each other are provided, of which the two outer bundles in each case form a loop at the root of the supporting wing to receive a bolt which has to be inserted in the loop perpendicular to the plane of the two fiber bundles. The inner bundle is turned down to form a second loop perpendicular to the first loop to receive a bolt which has to be inserted in and perpendicular to the plane of this loop. Both bolts act as connection members to attachment members on the fuselage.

Aircraft with supporting wings having members for taking up tensile and

In a structural member with large unidirectional rigidities unidirectional fiber bundles are completely embedded in shear resistant sheaths. The shear resistant sheaths are joined to a shear resistant torsion shell made up of skin layers by shear resistant vertical walls. A part of the vertical walls is shaped into stringers. Dividing layers (20) interrupting the passage of tension between adjacent unidirectional fiber bundles (30) are provided between the shear resistant sheaths (31) of the unidirectional fiber bundles (30).

Structural members with large unidirectional rigidities

In a wing with wing shells with good shear strength made of fibrous composite materials, particularly fiber-reinforced plastics, for aircraft, members taking up tensile and compressive forces are attached to the inside of the wing shells. These members have unidirectional fibers extending longitudinally of the wing. Stringers spaced longitudinally of the wing are provided on the inside of the wing shells, their fiber component being formed by a fiber ply joined to the fiber ply of the wing shell. Unidirectional fibre bundles are arranged between spaced stringers, the bundles being embedded with good shear strength in the synthetic resin matrix of the wing shells, extending longitudinally of the wing and having a substantially rectangular cross-section.

Aircraft wing

A rotor blade made of fiber-reinforced synthetic resin has a profile which, at least in the region of the blade tip is designed so as to be twistable by actuators about the rotor blade longitudinal axis. The torsion skin of the rotor blade in the region of the blade tip is designed anisotropically in the sense of a tension/torsion coupling and a controllable actuator, which acts in a longitudinal direction of the rotor blade upon the rotor blade tip, is disposed in the rotor blade spar. To achieve anisotropy, the torsion skin is a uni-directional winding having a winding angle of less than 45.degree. relative to the rotor blade longitudinal axis. The winding angle is dependent upon the force-to-displacement ratio of the actuator and may lie between 18.degree. and 40.degree.. In the region of the blade tip, the anisotropic torsion skin is disposed resting loosely on the rotor blade spar.

Growing community of inventors

Braunschweig, Germany

Matthias Piening