RU173125U1 - Stand for testing the mechanical strength of the design of an aircraft with an aerodynamic profile - Google Patents

Abstract

The utility model relates to the design of the stand, which provides the ability to test the mechanical strength of the structure of an aircraft with an aerodynamic profile. The stand contains a loading system. The loading system is connected to a mechanical load generating device and to distribution clamps located along the test structure. The loading system includes a drive traverse, intermediate traverses connected to it and distribution traverses connected in pairs with the corresponding intermediate traverses. Distribution traverses are located along the length of the tested structure and are connected by their rods to the corresponding clamps. The ends of the rods of the intermediate traverses are connected to the beams of the distribution traverses with the possibility of moving their connecting nodes to various positions along the specified beams. The technical result consists in the ability to simulate the loading of the aircraft structure at different angles of attack, which makes it possible to bring the test conditions of the structure closer to the conditions of its operation in real conditions. 1 s.p. f-ly, 5 ill.

Description

The technical field to which the utility model relates.

The utility model relates to the field of testing equipment and, specifically, to a test bench designed to test the mechanical strength of aircraft structures having an aerodynamic profile. Among the designs whose tests can be carried out at the proposed stand include mainly the wing of the aircraft, as well as elements of the mechanization of the wing: interceptor, aileron, flap, etc.

State of the art

A device for testing the structural strength of an aircraft wing is known, having a base on which the upper and lower multi-link frames, which are located respectively on the side of the upper and lower wing skins, are supported through hydraulic power exciters. On the frames there are elastic chambers in contact with the surfaces of the skin and connected to a pressure source. During the tests, the necessary distribution of loads on the wing surface is achieved by moving the upper and lower multi-link frames using hydraulic force exciters and simultaneously supplying the working medium from the pressure source to the elastic chambers (see SU 581787 A1). The device has a bulky, unreliable and inconvenient to use design due to the use of a two-sided loading circuit of the test object (from the upper and lower casing), requiring the use of a double set of loading means, due to the significant number of hydraulic force exciters, the use of elastic chambers and additional use of the source pressure for supplying a working medium to the chambers.

Similar disadvantages are characteristic of the installation for testing the strength of an aircraft wing, which also uses a two-sided loading scheme of the wing, and many hydraulic exciters, each of which serves to influence the wing load transfer unit attached to it. However, however, not elastic chambers, but covering the cuff wing, were used as load transfer nodes, which allows us to speak of a more reliable installation design (see US 2425273).

There is also known an installation for testing the strength of an aircraft wing, in which a lever mechanism located on the side of the upper skin of the wing is used, controlled by a power drive and bearing elements of local influence on the wing. At the same time, the installation does not provide for the use of a power unit for attaching the wing during testing, and the elements of local influence structurally do not provide coverage of the wing along the perimeter of its cross section, which is why it was necessary to introduce a bulky support unit into the installation, complicating both the structure itself and its maintenance ( see US 2383491, Fig. 2).

The closest analogue to the claimed utility model is an installation for testing the mechanical strength of an aircraft wing, which contains equipment for fixing the test object in a horizontal position during testing and a loading system connected to a mechanical load generating device and to load distribution clamps located along the specified object and covering it in the transverse direction (see US 4481817 A).

A disadvantage of the known installation is the ability to conduct tests exclusively with a fixed point of application of load, which allows simulating only the cruising flight mode during the tests. However, during a real flight, its mode changes, and therefore, the angle of attack changes and the load on the object changes. In a known installation, these features of the impact on the object in real conditions are not taken into account. In this case, the nodes forming the installation have a complex orientation in space, which complicates the maintenance of the installation.

Utility Model Disclosure

The objective of the utility model is to develop a test bench for the mechanical strength of the aircraft structure with an aerodynamic profile, with the determination of the VAT (stress-strain state) under real work under the action of a force equivalent to the aerodynamic pressure acting on the specified aircraft structure at flight.

The technical result achieved by the implementation of the claimed utility model consists in providing the possibility of simulating during the loading tests the structure of an aircraft having an aerodynamic profile at different angles of attack, which makes it possible to bring the test conditions closer to the operating conditions of the specified structure in real conditions.

To achieve the indicated technical result, a test bench is proposed for mechanical strength of an aircraft structure having an aerodynamic profile containing equipment for fixing the structure under test, a device for creating a mechanical load, distribution clamps located one after the other from the fixation section of the structure under test to the distal, in relation to the fixation area, parts of the structure, and covering the test structure, and the loading system connected with a device for creating a mechanical load and with distribution clamps. The claimed stand differs in that the loading system comprises a drive beam connected to a mechanical load generating device, intermediate beam and distribution beam connected to it, the number of which corresponds to the number of clamps made with the possibility of transferring the load to the test structure, and connected in pairs with the corresponding intermediate beam moreover, distribution traverses are located one after another along the test structure from the area of its fixation in the snap e and to its indicated distal part and are connected by their rods to the respective clamps, while the ends of the rods of the intermediate traverses are connected to the beams of the distributing traverses with the possibility of moving their connecting nodes to different positions along the specified beams.

Preferably, a hydraulic cylinder is used as a mechanical load generating device.

Brief Description of the Drawings

The utility model is illustrated by drawings, where:

In FIG. 1 schematically shows the proposed stand, in a perspective view;

In FIG. 2 - the proposed stand, front view;

In FIG. 3 - wing in cross section with a clamp covering it;

In FIG. 4 - one of the embodiments of the beam distribution crosshead, top view;

In FIG. 5 is a second embodiment of a distribution beam beam, top view.

Utility Model Implementation

The proposed stand provides the ability to test the mechanical strength of the structure of an aircraft with an aerodynamic profile. Tests are carried out to determine the SSS of the elements of the test structure, assess their stiffness and are associated with the need to conduct a structural strength analysis to describe the structural destruction process with subsequent experimental verification of the results.

Further, the description of the proposed stand is shown on the example of using, as a test structure with an aerodynamic profile, the wing of an aircraft.

The stand contains a power tool 1, which ensures the fixation of the wing 2 in a horizontal position during testing, and a loading system located above the tool, i.e. above the wing fixed in the snap-in 2. Power snap-in 1 should provide for the fastening of the test wing is the same as in the actual design of the aircraft (this condition must be observed when testing the elements of the mechanization of the wing of the aircraft). The specific loading system shown in FIG. 1 includes a drive traverse 3, two intermediate traverses 4 located under it and four distribution traverses 5 located under the traverse 4.

The beam 6 of the drive beam 3 through the rod 7 is connected to a device for creating a mechanical load, which is preferably used as a hydraulic cylinder (not shown conventionally in the drawing). The hydraulic cylinder must have a power reserve of at least 200 mm, and must also be equipped with a dynamometer with high measurement accuracy.

The rods 8 of the drive beam 3 connect the ends of the beam 6 with the middle of the beams 9 of the intermediate beam 4. In turn, each intermediate beam 4 is connected to its respective two distribution beam 5 by connecting the rods 10 of the beam 4 with the beam 11 of the beam 5. The distribution beam 5 is arranged one after another along the test wing 2 (along the length of the test wing), perpendicular to it and parallel to each other.

Turning to the specific layout of the stand shown in FIG. 1, it is necessary to pay attention to the specific and most preferred orientation of the traverses, namely: the drive traverse 3 and the intermediate traverses 4 are located in one vertical plane, and the distribution traverses 5 are oriented perpendicular to this vertical plane.

The beam 11 of each distribution beam 5 is connected by rods 12 to the corresponding distribution load clamp 13, which serves, together with other clamps, to directly transfer the load to the wing 2.

Distribution clamps 13 are located along the wing 2 along its entire length, one after the other, from the proximal fixation section of the wing 2 in the snap 1 and to the distal part of the wing relative to the fixation section, and cover the test wing in the transverse direction (i.e., around the perimeter wing cross sections 2). Of the four clamps, as shown in FIG. 1, the extreme clamp 13a is installed in close proximity to the power tool 1, and the second extreme clamp 13b is located on the end section of the wing 2. Each of the clamps 13 consists of two clamping jaws 14 and 15,

Mostly the beams of all traverses 3, 4 and 5 have a T-section.

The ends of the rods 10 of the intermediate traverse 4 are connected to the beams 11 of the distribution traverse 5, with the possibility of moving their connecting nodes 16 to different positions along the indicated beams 11. Such a permutation can be stepwise, in which independent sockets are made along the length of each beam 11 in its upper shelf 17 18. In the socket 18 of each beam 11, the connecting unit 16 of the corresponding traction 10 of the traverse 4 is fixed. However, the permutation can be stepless, for which, instead of independent sockets, a guide groove 19 is made in the shelf 17, in which rum fixed node 16.

The stiffness parameters of all elements of the test bench, as well as the kinematic parameters of the entire bench, should ensure a stable distribution of the load on the test structure throughout the test.

To maintain the stability of the load distribution during the experiment, the deformation of the stand elements should not critically change the nature of this distribution. Also, in order to minimize the impact of local bending moments (in the places where the clamps 13 are installed), which are inverse to the general bending of the wing 2, the joints of the clamps and rods with rotation axes 20 located not higher than the chord 21 of the wing 2 are provided (Fig. 3). The connecting nodes of the clamps 13 and rods 12 are located on the lateral vertical ends 22 of the clamps.

Testing the design of the wing of the aircraft at the proposed stand is as follows.

In the process of wing assembly, strain gauge sensors are installed, depending on the specified conditions for testing, in different positions: on the upper wing skin, on the lower wing skin, on the toe of the root wing rib, on the tail of the root wing rib, on the terminal rib of the wing, on the wing wall, on the wing fairing.

The test wing 2 of the aircraft is fixed in the power tool 1. In the corresponding positions of the wing 2, load-distributing clamps 13 of the distributing traverse 5 are installed. Clamps 13 are glued to the wing skins 2 through soft rubber gaskets on the inner surfaces of their lips 14, 15 (to avoid slipping of the clamps 2 along the wing). Intermediate traverses 4 are connected to the distribution traverses, connected to the drive traverse 3, which in turn is connected to the hydraulic cylinder.

Depending on the characteristics of the tests, the nodes 16 of the rods 10 of the intermediate traverse 4 are installed and fixed either in the middle of the beams 11, or with an offset relative to the middle of the beams 11. For this, in the first case, the connecting nodes 16 are fixed in the middle socket 18a, or in the middle of the guide groove 19 that allows you to simulate the cruise flight mode during the test. In the second case, i.e. when fixing the nodes 16 with an offset relative to the middle of the beams 11, for example, in the sockets 18b, the tests of the wing are carried out under real conditions under the action of a force equivalent to the aerodynamic pressure acting on the wing of the aircraft during flight. By installing the connecting nodes 16 of the rods in the sockets 18 or in the guide grooves 19 at different distances from the midpoints of the beams 11 (i.e., by changing the position of the connection of the ends of the rods and beams), it is possible to simulate the loading of the wing of the aircraft at different angles of attack, which makes it possible to approximate test conditions of the wing to the conditions of its operation in real conditions. The system of orientation of the traverse in space, adopted in the stand design, provides the most convenient access to the design units, which allows to significantly simplify the installation maintenance.

In the test process, the wing 2 is subjected to bending by means of its forced deflection through the traverse system 3, 4, 5. In the process of testing, the following indicators are recorded:

current load;

vertical movement of the attachment point of the hydraulic cylinder;

vertical movement of points Xb and Xf (Fig. 3);

strain gauge indicators.

Claims (9)

1. A bench for testing the mechanical strength of an aircraft structure having an aerodynamic profile containing mechanical load generating device, distribution clamps, located one after the other from the fixation section of the test structure in the tooling to the distal part of the structure with respect to the fixation section, and covering the test structure, and a loading system connected to a mechanical load generating device and to distribution clamps, characterized in that the loading system comprises a drive traverse connected to a mechanical load generating device, intermediate traverses and distribution travers connected to it, the number of which corresponds to the number of clamps, configured to transfer the load to the test structure and connected in pairs with the corresponding intermediate traverses, moreover, the distribution traverses are located one after another along the test structure from the site of fixing it in the snap to the specified distal part and are connected by their rods to the corresponding clamps, the ends of the rods of the intermediate traverses are connected to the beams of the distributing traverses with the possibility of moving their connecting nodes in different positions along the specified beams. 2. The stand under item 1, characterized in that the device for creating a mechanical load is a hydraulic cylinder.

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