RU2685792C1 - Panel testing device - Google Patents

Abstract

FIELD: aviation.SUBSTANCE: invention relates to testing of aircrafts for strength in complex multicomponent loading, in particular to tests of reinforced panels of aircraft airframe power frame, to determine actual strength and stability, as well as for selection of their rational configuration and laying of polymer composite material in various aircraft units, which take in operation compression (tensile), shear loads and transverse pressure flows. Device comprises power drive with supports for application of active and reactive forces, side walls with middle section with reduced stiffness, cross ties installed between side walls, elastically deformable plate connected with side walls, fixed panel with working section in central zone. On the elastically deformable plate there is a force exciter fixed, the rod of which is located in its middle part with the possibility of application of force to the panel, and along the edges of the middle section with lower rigidity there additionally installed are rigid frames with stops for the panel, which are located on the longitudinal axis of the panel.EFFECT: high reliability of obtained experimental data, as well as multifunctionality of device, without changing structure during assembly, and realizing the nature of deformation of natural long panel in simulation of various types of loading (compression + shift, compression + shift + transverse pressure; stretching + shift; stretching + shift + transverse pressure) in laboratory conditions.5 cl, 3 dwg, 1 tbl

Description

The invention relates to the field of testing of aircraft for strength, in particular, to the objects of testing for complex loading experimental reinforced wing and fuselage panels of the aircraft, made of polymer composite material (PCM) to determine the stability and carrying capacity while compressing (stretching), pressure and shear, as well as the choice of a rational configuration of reinforced panels in units of the RMB.

From the current level of technology (see patent RU 2490513 C2, G01N 3/24, published 08/20/2013) a sample (device) for testing diffusion bonding of sheet blanks for shear is known, consisting of two connected overlapping plates forming a diffusion joint having they lining located on opposite sides of the connection. The length of the working part of the sample is equal to the length of the overlap, which is at least a quarter of the height of the sample, the width of the sample is equal to at least half the length of the overlap. The known sample does not provide the possibility of testing for multi-component complex loading of reinforced panels made of polymer composite material.

Also from the prior art (see patent RU 127920 U1, G01N 3/24, published 10.05.2013) known sample and device for testing for eccentric compression of I-beams of metal profiles with holes in the corners on the upper and lower surfaces for fixing in the test device, and the device is additionally equipped with lower and upper support plates with retaining studs.

The specified sample and device do not provide the ability to test the reinforced panels of the RMB for combined loading (compression or tension, shear and lateral pressure).

In addition, an analogue of the claimed technical solution is a sample (device) for testing a reinforced panel, known from patent SU 1840335 A1, G01N 3/08, published 10.10.2006.

The specified sample for testing a reinforced panel consists of two parallel uncut three-span panels, two extreme and two middle ribs connecting the panels to each other and two side walls attached to the ribs. The sample is also provided with supporting hinge nodes, the outer cages of which are fixed on the respective extreme ribs, and the inner ones - on the ends of one of the uncut three-span panels, while the hinge axis lies on the line of intersection of the middle plane of the corresponding extreme rib with the plane parallel to the skin through the line of gravity centers cross sections of the panel. The specified sample does not provide the possibility of tests for compression (tension), shear and lateral pressure of the supported aircraft panels made of PCM, and protection of the device design at the time of destruction of the experimental panel of PCM.

It is also known a device for testing the compression of hinged support along vertical edges and plates of PCM clamped along loaded edges (see "Strength and stability of elements and connections of elements of aircraft structures made of composites". Moscow. Fizmatlit. 2013, p. 89-99 ).

The specified device does not provide the possibility of testing for complex loading.

Another analogue of the claimed technical solution is a device for testing the shear of a smooth plate made of PCM, fixed in a rigid square frame with hinged joints in its corners (see "Strength and stability of elements and connections of elements of aircraft structures made of composites." Moscow. Fizmatlit. 2013 , p. 89-99, p. 100, 105, 115).

The specified device does not provide the ability to test for complex loading of an experimental reinforced panel of the RMB.

An analogue of the claimed technical solution can also serve as a stand (device) for compressive testing of panels made of PCM, which includes a metal composite (see Utility Patent RU 148805, G01N 3/08, published 12/20/2014).

The specified device (stand) does not allow loading the experimental specimen by tension or compression, shear and internal pressure at the same time and to obtain the actual strength under complex loading realized during operation in an aircraft.

Another analogue of the claimed technical solution is a device for testing the compression of typical elements of the power frame of the airframe of an aircraft: multi-span reinforced panels in the laboratory. For testing, an experimental three-span panel equipped with strain gauges is used, with typical fasteners attached to it with transverse ribs or frames, side walls, which, in turn, are connected to the second identical panel, forming a closed system in the form of a caisson. Testing of caisson panels take place alternately, while on average test span conditions are realized for supporting a full-scale constructive panel at its junction with ribs or frames that are close to real (see scientific journal “Research of the Science City”, No. 1 (11), 2015, p. 32-39).

The specified device for testing does not provide its versatility and the ability to test for complex multi-component loading panels of the center section, wing and a number of other units of the airframe of the aircraft (LA).

A device for testing the compressive strength of an experimental reinforced panel, consisting of two identical parallel three-span panels with a valid middle part, on which strain gages are installed, is known. The panels are interconnected by four ribs joined together by a typical fastener with a pair of side walls. The panel is loaded using a power drive, for example, a testing machine by moving an active crosshead, including an adjustable spherical hinge, or by means of energizers associated with an oil pump station (see “Air Fleet Technique”, 1986, No. 1, p. 70-73). The specified device does not provide multifunctionality and the ability to test with complex loading of the aircraft panel, made of RMB.

The closest analogue (prototype) of the claimed technical solution is a device for testing panels for strength under complex two-component loading by compression and shear (patent RU 2653774, G01N 3/10, published on 14.05.2018).

The device consists of a power drive with supports for the application of active and reactive forces, fixed panel, connected along the longitudinal edges with the shelves of the side walls of the channel section, with middle sections of reduced rigidity in the area of the working section of the panel, pivotally fixed bends, creating a loading device bending along the edges and The reaction of the supports supports are axially symmetrical at the corners of the middle span of the panel made of PCM, two biases connected with safety devices, two axes, brackets, with side walls, transverse screeds connected only to the side walls, and an elastically deformable plate connected to the shelves of the side walls opposite to the experimental panel side and paired ribs on the outside of the device.

The specified device for testing does not provide the possibility of complex multi-component loading of panels of various aircraft units.

All these known devices allow us to determine the strength and stability of the elements of the power frame of the aircraft only with simple uniaxial loading or two-component loading (compression with a shift).

The disadvantage of all the above technical solutions is the lack of laboratory conditions, the possibility of testing with complex multi-component loading of wing panels, center section, fuselage and a number of other airframe units, simulating tensile, compressive, shear and lateral pressure flows acting on them in operation, in a certain combination at the same time. Not provided as their multifunctionality.

The task to be solved by the claimed invention is to develop a device design that improves the accuracy of reproducing the working conditions of a reinforced aircraft frame carcass panel, made, for example, of PCM with a combination of different power options without changing the metal part of the device structure itself.

The technical result of the claimed invention is to increase the reliability of the experimental data obtained, as well as the versatility of the device, without changing the design during assembly, and the implementation of the nature of the deformation of the full-length panel when simulating various types of loading (compression + shear, compression + shear + transverse pressure; tension + shear; stretching + shear + lateral pressure) in laboratory conditions ..

The solution of the task and obtaining a technical result is achieved by the fact that in the device for testing panels containing a power drive with supports for the application of active and reactive forces, side walls with a middle section with reduced rigidity, transverse screeds placed between the side walls, an elastically deformable plate connected to the side walls, the fastened panel with the working area in the central zone, while on the elastically deformable plate there is attached an exciter, the rod of which is located in its middle Asti to apply a force simulating a lateral pressure on the panel, and the edges of the middle portion with low rigidity is further mounted a rigid framework with stops for a panel located on the longitudinal axis of the panel. The stops for the panel are made adjustable, the actuator contains two intersecting beams mounted on the supports, the actuator rod is made with a replaceable tip. The device further comprises a dynamometer and a displacement sensor connected to the energizer.

Brief Description of the Drawings

Details, features, and advantages of the present invention follow from the following description of an exemplary embodiment of the claimed device using the drawings on which is shown:

FIG. 1 - Device for testing power-driven panels (rigid frames with stops are not shown).

FIG. 2 - Loading scheme with active P, reactive R forces and pressure q (Q) of the PCM panel in the metal part of the device (exciter and rigid frames with stops are not shown):

a) compression and shear modeling;

b) modeling of stretching and shear;

c) modeling of internal pressure;

d) simulation of external pressure.

FIG. 3 - the device in a section in a zone of a working site:

section A-A - I - modeling external pressure;

section A-A - II - modeling of internal pressure;

BB section - rigid frames with stops.

This device can be used to create complex multicomponent loading at the same time by the efforts of compression (tension), shear and lateral pressure in laboratory conditions supported by airframe panels of the aircraft. It contains the actuator 1, consisting of two intersecting power beams, for example, channel section, mounted on four pillars (two of them with adjustable rod) and attachment points located in the working space of the test press transferring the load (shown by the arrow in Fig. 1 ) on the power drive, the metal part of the device 2 for deforming the panel 3 (for example, from PCM) by active and reactive efforts in a certain combination with a different position of the panel, simulating also the internal or external pressure Tension (compression) and shift in the working section 4 of the fastened panel, exciter 5 with a dynamometer, displacement transducer and rod 6 with an interchangeable tip passing into the central hole of the elastically deformable plate 7. The latter creates a transverse load (pressure) in the working section of the panel , and the edges of the working area, limit two rigid frames 8 with adjustable (for example, height) hemispherical supports 9, resting on the panel along the longitudinal central axis 10, as well as transverse (internal) couplers 11. In this case, metal The cushion part of the device 2 contains side walls with a middle section with reduced rigidity, transverse ties 11 placed between the side walls, an elastically deformable plate 7 connected to the side walls and serves to secure the panel with the working section 4 in the central zone.

To create external force effects, as in the designer, the orientation of the device relative to the power drive changes, the direction of action of the active and reactive forces and the place of their application, as well as the connection of the energizer, which creates a transverse force that simulates the distributed pressure on the working section of the panel, and the PCM of the panel in metal parts of the device.

To create a stress-strain state in the working area of the PCM (compression + shear) or (stretching + shear) two intersecting power beams and supports are reversed, with a constant direction of force in the test press (Fig. 1 and Fig. 2), and the third component of the load is created by the energizer through a rod with a replaceable tip (Fig. 3).

The arrangement of the PCM panels in the device allows you to create either external or internal transverse pressure, and in combination with tension (compression) and shear, three-component loading (triaxial stress state), described by the stress ellipsoid (Feodosyev VI, Resistance of materials, pp. 239-243 .GIFML. 1963). In the prototype, a biaxial, flat stress state is realized, only compression with a shift. In the process of loading, the deformed state is fixed by strain gauges installed on the working section of the panel, as in the prototype.

The device is multifunctional, as a designer, when combining the panel layout of the RMB, the nature and location of external forces without changing the basic design.

Using the described device allows you to increase the reliability of the experimental data obtained, due to the simultaneous loading of the panel from PCM with a combination of efforts, by 15-20%, simulating in laboratory conditions the process of real deformation of the full-scale panel of the aircraft frame of the aircraft. At the same time, various typical variants of force action are reproduced. If necessary, you can also evaluate the strength of fasteners in the panels.

The need to test panels of the power cage made of PCM under conditions close to operational ones is governed by aviation rules and Pyramid requirements (Appendix: General scheme ..., Table 1) of computational and experimental strength studies, which are necessary to substantiate the correctness of material choice, design solutions, strength criteria, technological operations, validation of methods for calculating and certifying the design of the airframe of the aircraft, while the use of the proposed device allows It goes from the 4th level (“Pyramid”) to the 5th level, complexly modeling the complex processes of real deformation of the power elements of the structure.

Claims (5)

1. Device for testing panels, containing a power drive with supports for the application of active and reactive forces, side walls with a middle section with reduced rigidity, transverse screeds placed between the side walls, an elastically deformable plate connected to the side walls, fixed panel with the working section in a central zone, characterized in that an energizer is fixed on an elastically deformable plate, the stem of which is located in its middle part with the possibility of applying a force on the panel, and on the edges of the middle section In addition, rigid frames with stops for the panel located on the longitudinal axis of the panel are installed with a reduced rigidity. 2. A device for testing panels according to claim. 1, characterized in that the stops for the panel are made adjustable. 3. A device for testing panels under item 1, characterized in that the power drive contains two intersecting beams mounted on supports. 4. A device for testing panels under item 1, characterized in that the actuator stem is made with a replaceable tip. 5. A device for testing panels according to claim. 1, characterized in that it additionally contains a dynamometer and a displacement sensor connected to an energizer.

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