aircraft wing spar

Spars - These are butt knots of wings, which are part of compensatory knots. In addition to the spars, the compensators are also referred to as under-ramps, various suspension brackets and so on. This is the longitudinal main element of the aircraft power pack. It performs the function of transferring tensile, bending, compressing and other types of loads. There are several types of spars - girder, girder, beams, trusses, box. In addition, the spars participate in the perception of the shearing force. Box and round cross-sections of spars are capable of perceiving a turning moment.

In aircrafts spars are aligned with the longitudinal stringers and create a set of wings, tail, fuselage, ailerons and rudders.

Design

From the structural point of view, the spars are teams or monolithic. Extra spar has the upper and lower belt and the wall. Box section has only two walls. On the wall of the belt are joined by riveting, spot electric welding, bolting or gluing. Belts of the bending moment working on the tension-compression. They make up a large part of the total cross-sectional area of ​​the spar.

Monoblock wing - A type of the wing structure, in which the flexural strength perceived longitudinal stringers and a covering over the whole cross loop. In such wing spars there, but instead they establish longitudinal walls.

Belts spar are of high quality materials:

• steel;
• titanium;
• aluminum alloys.

When you create a cross-sectional shape designers are guided by a particular task - to gain the maximum moment of inertia for a given cross-sectional area, ease of production, ease aging profile, economy and consolidation of facilities to cover and walls.

According to the width of the elongated shape of the cross section profile increases the moment of inertia of the spar. Due to the presence of zones feet area which is occupied by holes for rivets, it becomes small, and the mounting wall and the cladding to the belt much easier. Profile wing held by small forging profiles and their feet, but if it is possible. In another variation on the Belt set pad of soft material.

Applying different profiles section, one can measure the area of ​​the sectional zones in length. The destruction of the belt is formed by compressive stresses within the material of equal strength. This zone is not working the entire area, but only part of it, which is equal to the area of ​​the belt.

Critical compression stress zones beam spar

The two planes belt beam spar supported by rigid elements - wall and cladding. They prevent the curvature of the axis of the belt, resulting in no loss of stability. Critical voltage determined in the same manner as that of the stringers.

The walls of the beam spars are produced primarily from sheet materials. Thin wall reinforcing struts are generally angular cross-section. The main task of reception - be divided into several wall panels and to improve the critical shear buckling stress, depending on the ratio h / a and wall thickness.

The design of the spar is one or two walls. Critical voltage biasing the wall is much less than fat. For this reason, a thick wall is advantageous in a weight ratio than two thin, which are designed for the same load.