SU729483A1 - Device for securing tlanar specimen - Google Patents

Description

I

The invention relates to the field of testing materials and can be used to secure samples of materials when tested in a complex stress state.

There are known devices for fastening samples: specimens made in the form of a closed spatial frame, having a hinged system of mechanical feedbacks. At the point of application of transverse force, a T-shaped yoke with two degrees of freedom is installed on the inner annular surface of the upper seal, and at the point of application of the axial force there is a clamping hinge with two eccentric washers 11.

However, such devices do not provide the ability to create simultaneous shear and tensile-compressive forces.

The closest in technical essence and available result to the invention is a device for securing a flat sample during its tests, containing grips for the sample and the holder, which consists of a parallelogram link 2.

However, in such a device, it is impossible to create simultaneous shear forces and tensile forces - compression of the test sample.

In order to provide the possibility of additional uniaxial loading in the proposed device, the grippers are mounted in cages with a possibility of movement in directions perpendicular to the sides of the parallelogram, and are equipped with means for fastening them to the additional loading device.

FIG. 1 shows the scheme of the proposed device; ka fig. 2 is a view along arrow A in FIG. one; in fig. 3 shows a section BB in FIG.

A device for securing a flat specimen with its tests contains a geometrically adjustable parallelogram consisting of identical links of clips 1 articulated with cylindrical hinges 2, on which means of attachment to a loading device, such as a fork 3, are fastened.

Claims (2)

The sides of sample 4 are fixed by grippers 5, which are mounted in cages with the possibility of moving them in directions perpendicular to the sides of the parallelogram. The assembly can be performed, for example, in the form of carriages attached to the grippers 5 moving relative to the sleeves 1 or by means of guides with which the sleeves and grippers are provided, between which rolling elements - balls 6 are arranged. As means of attachment to the loading device eyelets 7 can be used to the grippers. The device for loading the sample 1 is more compressive (see Fig. 1) along the Y axis (the loading device is conventionally not shown) includes energizer 8 (hydraulic cylinder), crossheads 9, mounted on them radial spherical Kie bearings (not shown), the locking member 10 with a holder 11, load cell 12 (see. FIG. 3). . A device for loading a sample into stretching is characterized in that instead of the day of the meter, a rigid rod is installed, and the dynamometer is connected to the chain in series with the sample. When using strain gauge dynamometers working in compression and tension, both the load and the tool can be made according to the scheme in FIG. 3. When testing a sample, 4 shear forces are applied to it by tilting a parallelogram by applying tensile forces to the forks 3 in a test machine. Simultaneously with the shear, the specimen can be loaded with ni compression along the X axis and stretching along the Y axis (SMFIG. 1). To compress the sample into plate 8, fluid is injected so that its stem engages. Oppositely applied means for securing the sample 3, freely moving on the balls 6 along the guides, will transfer the load to the sample. The readings of the danamometer 12 taking into account the helium trier 9 determine the load applied to the image. The spread load is applied to the specimen with the opposite movement of the valve. When tilting the parallelogram, the displacements of the links of the clips 1 and the elements with which the compressive or tensile loading devices are connected are displaced, which leads to the displacement of the axial line of application of the load and the appearance of a bending moment in the sample plane. In order to prevent this phenomenon, the hodrocklinder 8 is secured with the help of a holder 11 on a clamp 10, which is installed with its grooves on elongated axles 2. When the geometry of the four-axle axle 2 changes, it slides freely in the slots of the clamp, while the immobility and the hydraulic cylinder associated with it are secured. relative to the center of the sample, which eliminates the displacement of the axial LIKIN application of the load. The elements 5, in turn, move their bearings relative to the cross arms 9 along the bearings mounted on them through which the load is applied. The device allows differentially loading loads to the sample in the following combinations; shear with simultaneous compression on axis X and Y; shear with simultaneous stretching in axes X and Y; shear with tension along one axis and compression along another. The invention The device for securing the GTL sample during its tests, containing the grips for the sample and the holder, the parallelogram setting links interacting with the loading device, so that, in order to provide the possibility of additional uniaxial loading, The grippers are mounted in cages with a possibility of movement in directions perpendicular to the sides of the parallelogram, and are equipped with means for fastening them to an additional load on the device. Sources of information taken into account when examining 1. USSR author's certificate number 150678, class, G 01 N 19/00, 1961. 2. Smirnov V. I, Meshcherkov V. V. Testing and control of building fiberglass. 1965, p. 36 (prototype).