aircraft Stringer

Stringer aircraft. Stringer wing aircraft


Stringer - a longitudinal element of the power set of plane which is associated with the ribs and the wing skin or fuselage frames. The main purpose is the thrust of compression and tension. Stringer also accepts local aerodynamic loads, trim secures and enhances its rigidity.

Depending on the location and destination of the local stringers can gain typical, butt, and head-end. By strengthening local refers to the location of the stringers places where the focus the load or on the edges of the cut-outs in the casing. Play-stringers are lining the joints, types provides whole rigidity.

Modern aircraft are distinguished by new stringers from bent and extruded profiles in increments of 150-400 mm. In the areas of possible cracks to increase the survivability of the entire structure in the skin are put stringers of strong materials, acting as cracks limiters, - stoppers. Some power circuits have powerful stringer sets, where the spars of the spars are rather weakly expressed. In such cases, the cross-sectional area of ​​the spars is of the same order as the cross-sectional area of ​​the stringer. Therefore, stringers differ from longitudinal members by a weak section.

The functions are determined by the constructive and power circuit. In the wing of the spar type, the stringers act as reinforcement of the skin to enhance its tangential critical stresses when the wing is operated on bending and torsion. They take part in the transfer of aerodynamic load directly to the ribs. In the monobloc wing, in addition, the stringer set, together with the skin, takes most of the bending moments. Sheathing and stringers at the same time work on decompression and compression, they are subject to regulatory stresses. The weight of the stringer varies depending on the design of about 12% of the total weight of the wing.

Furthermore, the fuselage stringers perform its role in accordance with the diagram. The monocoque (fuselage stringer) load perceived skin, which is supported by a large number of stringers, and in some cases may include a set of spars. This type is used in the fuselage IL-96, Tu-154, SSJ. The spars, fuselage stringer in those parts where you have to make huge cuts applied spar circuit passing in stringer, due to the addition of stringers and longerons cross sections decrease. A striking example - the MiG-15.

Forms section

There are several types of sectional forms stringers:

  • Curved;

  • Pressed;

  • closed;

  • open.

Interrupted profiles have a higher critical compressive stress than the bent shapes of identical sections and equal to the area of ​​the cross member. For this reason, in compressed panels monoblock wing stringers are mainly used in extrusions. Bent shape of the profile used for the stringers, which under main load acting on the wings of the tension. Closed profile with paneling forms a closed loop, ensures that higher voltages than equal in cross-sectional area at the other types.

To reduce the mass and create equally robust construction stringers are created along the span of the variable cross-sectional area which diminishes toward the end of the wing. The wall thickness of stringer normally varies 0,5-3,0 mm.

stringer maximum load

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