SU1250904A1 - Method of tension testing of specimens of anisotropic materials - Google Patents

Abstract

The invention relates to a testing technique and can be used to determine the mechanical properties of anisotropic materials, for example ceramic materials, when they are tested for stretching. The aim of the invention is to expand the technological capabilities of the method when testing fragile materials, for example ceramic materials, by providing for testing flat samples of arbitrary shape. A flat sample of arbitrary shape, for example in the form of a disk or a plate, is placed between two identical parts of an elastic pad, the cross sections of which coincide with the cross section of the sample. Through an elastic gasket, the specimen is subjected to a compressive load and is brought to fracture. The elastic gasket is made of a material whose Poisson ratio to Young's modulus exceeds this ratio for the material of the test sample. In addition, the material of the elastic strip forms with the sample material a friction pair, which prevents slippage of the parts of the elastic strip relative to the plane of the sample. Since the magnitude of the transverse deformation of the elastic gasket is higher than that of the sample material, tensile stresses arise in the sample under the action of a compressive force. With increasing compressive stress, the magnitude of the tensile stress increases, which leads to the destruction of the sample from the action of tensile stresses. The fixer, the magnitude of the compressive force at which the specimen was destroyed, is determined by the tensile tensile stresses by the known formulas of the theory of elasticity. 1 il. § (L from to eaten about with

Description

Portray. Ptge from: -s1Sits x test equipment and can be used ;: - zozano prt-i ana lk e mechanical properties a -; -; Single materials, in particular for determining the strength of brittle materials, for; 1 is an example of ceramic materials, for tensile testing.

The purpose of the invention is to expand the technological capabilities of the method when using xr-resistant materials, for example, ceramic materials. Ways to ensure the testing of the RCS QC: samples of arbitrary forR P GT:,.

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The test method and the dissemination of samples of anisotropic g-teriases are carried out as follows.

Flat sample 1 of arbitrary shape from the material under study with anisotropic properties, for example, from Karamiki ,. placed between two single parts 2: h 3 of an elastic gasket, the cross sections that coincide with the cross section of the sample, forming a three-layer package, and the got package are placed between the load of 4 kg; 5 pressy (not shown;, pseEolus- to regulate and measure agr;; t,.) Sample 1 is carried out before fracture, the magnitude of the force during the fracture is recorded and the strength of the material to be measured is measured by it. The material of parts 2 and 3 of an elastic gasket uses material, the ratio of the Poisson's ratio to the Young's modulus which exceeds this ratio. Ф1 of the material of the test sample ... In addition, the material of parts 2 and 3 of elastic elastic //, must form a friction pair with sample material 1. , which eliminates the slippage of parts 2 to 3 of the elastic strip relative to the sample plane of 1 g,

In iipon.ecre squeezing, parts 2 and 3 of the elastic pads are deformed in the longitudinal and transverse direction. Together with them, sample I also undergoes deformation both longitudinally under compressive load and transverse from contact with parts 2 and 3 of an elastic gasket. Since the lateral deformation of an elastic gasket is higher than that of sample material s,. This is due to the test of the pk .y .-. gga of the defensive parts.

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3, tensile stresses appear in the sample material. With an increase in compressive stress, the magnitude of the tensile stress increases and, taking into account the anisotropy of the properties of the test material, namely that the resistance of the ceramic material to stretching is more than an order of magnitude lower than the compressive strength, the destruction of the sample

10 occurs under the action of tensile stresses. The magnitude of the breaking tensile stresses is determined by the known formulas of the theory of elasticity.

Example. The test is subjected to samples from piezoceramics CTBS-3, PZT-19, PZT-21, PZT-83G and TV-2 in the form of disks with a diameter of 8 to 20 mm and a thickness of 0.3 to 4 mm. Young's modulus more than 0.6-10 kgf / cm, Poisson's ratio of 0.25-0.4. Plexiglas with a Young's modulus of 0.05–10 kgf / cm and a Poisson’s ratio of 0.35 was used as the material of the parts of the elastic gasket. For specimens from PZTBS-3 piezoceramics with a diameter of 20 mm and a thickness of 1 mm, destruction occurs under compressive force from 8AO

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TO 650 kgf, for TsTS-19 with a diameter of 10 and a thickness of 1.4, respectively, from 420 to 340 kgf.

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Claims (1)

Invention Formula A test method for stretching samples of anisotropic materials, in which an elastic pad is brought into contact with the test specimen, a compressive force is applied to it, the specimen is brought to fracture, and the force at breakage is recorded, material, characterized in that, in order to expand the technological capabilities of the method when testing fragile materials such as ceramic, by providing a test flat pattern. An arbitrary shape, the gasket is made with a cross section that coincides with the cross section of sample j in two parts to place the sample between them and is made of a material whose Poisson ratio to the Young's modulus of which exceeds this ratio for the material of the test sample and which forms a friction pair with the sample material. 7 /////////