SU819566A1 - Method of measuring internal stresses in materials - Google Patents

Description

one

The invention relates to the field of measurement technology.

A known method for determining the internal stresses in materials is that a hole is drilled in the material and the deformation displacements are measured by which internal stresses 1 are judged.

The disadvantages of this method are the low accuracy of the determination of internal stresses, due to the fact that only one hole is used to determine internal stresses, as well as the impossibility of determining extreme stresses and components of the stress tensor.

The closest in technical essence and the achieved result to the proposed method is a method of measuring internal stresses in materials, which consists in that two holes are drilled in the material and the deformation displacements are measured, according to which internal stresses are judged 2.

The disadvantages of this method are the comparatively low accuracy of the determination of internal stresses, due to the fact that, when the holes are placed separately, the determination of stresses is performed over a large area of the material under study, as well as the impossibility of determining

extreme stress and all stress tensor components.

The aim of the invention is to increase the measurement accuracy.

The goal is achieved by the fact that one of the holes is made In the form of a ring, "about axially to another hole made cylindrical, to a depth exceeding the depth of this hole.

To determine extreme stresses, a cylindrical hole is first drilled, its shape is determined, a ring hole is drilled, the shape of a cylindrical hole is again determined, compared to the original hole, and extreme stress stresses in the material are judged by changing the shape.

To determine the components of the stress tensor, the energizers associated with the dynamometers are installed on the surfaces of both openings on the surfaces of the openings: complete compensation of the deformation displacements, measured forces required for compensation, and

the magnitude of the effort received is judged on the components of the stress tensor.

FIG. Figure 1 shows a device for determining the components of the tensor along the surfaces of the holes, side view; in fig. 2 - then

same device, top view; in fig. 3 shows an embodiment of a method for measuring internal stresses in materials; in fig. 4 - changing the shape of a cylindrical hole and determining extreme stresses.

The device for measuring internal stresses in materials comprises a housing 1, in which air chambers 2 are located with plungers 3 connected to pressure elements 4 moving along rails 5. Chambers 2 are sealed with rubber gaskets 6, gaskets 7 and 8 serve to reduce local stresses when the device is in contact with the surface of the material under investigation, element 9 is for securing the device.

The method for measuring internal stresses in materials is as follows.

First, a cylindrical bore 10 is drilled (FIG. 3), its shape 11 (FIG. 4) is determined by measuring radial vectors, then a bore 12 is drilled coaxially (FIG. 3) into an annular groove exceeding the depth of the bore 10, and A change in the shape 13 (Fig. 4) of the hole 10. A device is installed in the hole in the form of a ring for carrying out the method according to L. 3. Chambers 2: air is supplied at such a pressure so as to achieve complete com- bination of the deformation displacements, and the pressures in the chambers are measured. The plungers 3 act on the pressure elements 4, which, moving along the guides 5, compensate for the deformation displacements. By varying the size and shape of the cylindrical holes, internal stresses and both extrema are judged, respectively, and by components of the stress tensor, by the pressure in the air chambers.

The proposed method allows to increase the accuracy of measurements due to coaxial drilling of holes and the consequent greater localization of internal stresses. This makes it possible to determine extreme stresses by determining the shape of the cylindrical hole and the components of the stress tensor by determining stresses required to compensate for the deformation displacements caused by drilling the hole in the form of an “o-groove.

Claims (3)

1. A method for measuring internal stresses in materials, consisting in that two holes are drilled in the material and the deformation displacements are measured, by which internal stresses are judged, characterized in that in order to improve the accuracy of measurements, one from the holes, they are made in the form of a ring coaxial to another hole, cylindrical, to a depth exceeding the depth of this hole. , 2. The method according to l. 1, so that, in order to determine extreme stresses, a cylindrical hole is first drilled; shape, drill a hole in the form of a ring, re-determine the shape of a cylindrical hole, compare it with the original and, by changing the shape, judge the extreme stresses in the material. 3. Method according to claim 1, characterized in that, in order to determine the components of the stress tensor on the surfaces of both holes, force-exciters associated with dynamometers, fully compensate for the deformation displacements, measure the forces required for compaction, and judge the components of the stress tensor by the magnitude of the received effort. Information sources, taken into account in the examination 1. USSR author's certificate number 518615, cl. G 01B 5/30, 1974. 2. USSR author's certificate NO 575471, cl. G 01B 7/18, 1973 (lrotype). fpu2.i fO 12 Fig.Z