SU1370444A1 - Method of determining strains in article - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to reduce labor intensity. For this, the sign of the stresses in the product is determined. The method consists in measuring the diameters of the prints of the indenter in the test article and the reference sample made of the product material, and in determining the stresses from the data obtained. The new method is to determine the sign of the stresses in the product by comparing the diameters of the prints in the product and the reference sample and loading the indenter with a force of P (1-4) D, where P is the indentation force of the indenter; D is the diameter of the indenter.

Description

with about

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The invention relates to a measurement technique and can be used to determine stresses in various products.

The aim of the invention is to reduce the labor intensity by determining the sign of the stresses in the product.

The method is carried out as follows.

A reference sample, in which there are no residual stresses, is made from the material of the investigated product. The indenter is pushed into the surface of the test article and the reference sample. A ball with a diameter of 10 mm is used as an indenter. The indentation force of the indenter is selected from the condition (l-4) D, where P is the indenter pressing force, n; D is the diameter of the ball of the indenter, m

Compare the diameters of prints on the surfaces of the reference (and the test (d.y) products and from

comparisons determine the sign of the stresses in the product under investigation. If the diameter of a print on a test article is larger than the diameter of a print on a reference item, then tensile stresses occur in the test item. If the diameter of the print on the test article is less than the diameter of the print on the reference item, then there will be compressive stresses in the test item.

Then, the reference sample is loaded in an elastoplastic area with a tensile load, if tensile stresses or compressive stresses occur in the product, if compressive stresses occur in the LII product again press the same indenter into the surface of the investigated article with a force chosen from condition P (1 -4) D, measure the diameter (d ,,) of the fingerprint in the reference sample under load, and from the data obtained determine the voltage in the test article using the formula

 uh, "

1 Aml

Ig g

QMJ

Ig

d. j.M.H

where is 6

z.and

 z.and

.U

stress in the reference sample when loaded with its tensile or compressive load; the diameter of the imprint on the surface of the investigated product;

the imprint diameter on the surface of the reference sample prior to loading; imprint diameter on the surface of the reference sample under load.

Claims (1)

Invention Formula The method of determining the stresses in the product, consisting in that an indentor is pressed into the product under investigation and the imprint diameter is measured, a reference sample is made from the material of the test article, an indenter is pressed into its surface and the imprint diameter is measured, the reference sample is loaded into the elastic-plastic region, the indenter is again pressed into its surface, and the diameter of the obtained imprint is measured and, according to the data obtained, the stresses in the product are determined in order to reduce the labor intensity the indentation is selected from the condition P (1–4) B, where P is the indenter indentation force, D is the indenter diameter, and the reference sample is loaded with a tensile load if the imprint diameter on the test article is larger than the imprint diameter on the reference specimen, and compressive load, if the diameter of the print on the tested product is less than the diameter of the print on the Reference sample.