SU1596227A1 - Device for tensile testing of ring-shaped specimen - Google Patents

Abstract

This invention relates to tensile strength testing of ring specimens. The purpose of the invention is to improve the accuracy of testing by eliminating the bending moment on the sample. The device for loading the annular sample 4 comprises a housing 1, an expanding element 2 and a mandrel of N sectors 3 supported on the shoulder of the housing 1 and interacting with each other, the sample and the expanding elements. The end surfaces of sectors 3 are bevelled at an angle of 30 ° * 98A 0 * 9860 ° and FORMING ANGLE ϕ / 2 C on the SIDE SURFACE M. PERFORMANCE AGAINST MECHANICS 1 hp ff, 2 ill.

Description

This invention relates to a testing technique, namely to testing tensile strength of ring samples.

The aim of the invention is to improve the accuracy of testing by eliminating the bending moment on the sample.

FIG. 1 shows a diagram of the device; in fig. 2 is a section A-A in FIG. one.

The device comprises a body 1, made in the form of a continuous cylinder with a collar (the end of the cylinder is shown in Fig. 1 by a dashed line), an expanding element 2, covering the cylinder of the body, and a mandrel from n sectors 3 supported by the body collar 1 and interacting with sample 4 and Expansion element 2 “The end surfaces of sectors 3 are beveled at an angle o, to the planes of the ends of the mandrel and form an angle with the lateral angles m. The sectors are set up in such a way that they interact with each other along lateral surfaces, and with the collar of body 1 and element 2, facets a and b, respectively, as shown by the sector sweep fragment in FIG. one.

The device works as follows.

Sample 4 is placed on the mandrel of the sectors 3 and the assembled device is installed on the press plate. Under the action of compressive force P, the sectors are evenly slipping relative to each other along their lateral surfaces, while the size H0 decreases and L increases. Thus, the outer diameter of the mandrel increases, which simulates the effect of internal pressure on the sample 4.

The pattern acting on the sample is determined for the current value of the angle o (according to the calibration dependences, taking into account the effect of friction forces, when the sectors move relative to

each other, a collar of the PI housing of the expansion element. The magnitude of the forces of friction will be less, the smaller the angle /. However, in order to obtain maximum increments of size L, it is necessary to increase the angle. Taking into account possible increments of L, related to the ductility of the test specimens,

O it is advisable to choose the values of the angle o (from the condition 30 0 / J 60. When testing hrz materials, the angle o (d 45 is optimal.

The increment of the perimeter of the mandrel during the test is determined by calculation from the heights Hj measured by limestone methods.

Thus, the proposed device provides uniform loading of ring specimens by means of imitating internal pressure without creating a bending moment over the interaction surface of the mandrel.

with sample.

Claims (2)

1. Device for testing Q tensile annular specimen, contents A cylindrical housing mounted on a body of a cylindrical mandrel from n sectors and an expandable element that interacts with the 1st sectors. In order to improve the accuracy of the test by excluding the bending moment on the sample, the body is made in the form of a solid cylinder with a shoulder, the surface- sector spines are sloped under the sharp. angle to the planes of the end faces of the mandrel and form an angle / 2 with lateral edges of 1 ш sectors, sectors are supported on the shoulder of the body, and the expansion element is made 5 in the form of a ring. 2. The device according to claim 1, characterized in that the angle c (selected from the condition 30 60. FIG. g