SU1422833A1 - Double-cantilever prismatic specimen - Google Patents

Abstract

The invention relates to an injecting technique and can be used to determine the mechanical properties of materials. The purpose of the invention is to improve the accuracy of determining the fracture toughness and the increase in the range of it and aluminum alloys. Prismatic, the sample contains a chevron incision 1, forming two consoles 2 and 3 in the sample. The height H of the sample is chosen from the condition Od.832B - H 0.848B, where B is the width of the sample console, the length W of the working part of the sample is chosen from conditions 1.072V, 08BB, and the width of the cut is chosen from the condition O, 056B "G i 0.072B. In order to determine the fracture toughness, the sample is introduced from the material preform. The loading is carried out on a testing machine by applying force to the console. .2 and 3 specimen. In the notch 1 zone, a stress state of off-center tension arises. The loading is carried out before the formation of a crack from the top of the notch. When loading, the force is recorded and judged by the viscosity of the failure of the ma-. teriala. 4 il. ё (L s

Description

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The invention relates to the engineering technique and can be used to determine the mechanical properties of the materials.

The purpose of the invention is to improve the accuracy of the determination of the fracture toughness and increase its measurement range for alcuminium alloy.

FIG. 1 shows a double prismatic chevron notch in FIG. 2 is a view A of FIG. one; FIG. 3, section BB, FIG. 2j in FIG. 4 —the section in FIG. 3,

The prismatic sample contains a chevron notch 1, forming in the sample two cantilevers 2 and 3, the height H of the sample is chosen from the condition of 0.832 V

 H 0.848 V, where B is the width of the sample's role, the length W of the working part of the sample is chosen from the condition B 4 W and 1.088 b; and the width of the V rifling is chosen from the conditions of 0.056 s / 0.072 V. ..

When the height H of the sample is less than 0.832 or greater than 0.848 of the thickness B of the sample, the accuracy of the determination of the fracture toughness is lost due to the change in the yield property of the length of the specimen. As the compliance is a very sensitive characteristic of the sample geometry

When performing the length W of the working part is less than 1.072. or greater than 1.088 of the sample thickness B, loss of accuracy in determining the fracture toughness occurs, since in this case the specimen compliance differs from the quadratic dependence and the resulting fracture toughness values are strongly influenced by the critical crack length,

When an incision width f is made less than 0.056 or greater than 0.072 of the specimen thickness B, accuracy is lost in determining the fracture toughness due to a change in the crack growth conditions.

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, 1 l determine the fracture toughness of the sample is cut out of the workpiece material. To determine the anisotropy of the mechanical properties, various samples are cut in different directions. The loading is realized on the test line. machine by applying force to the sample consoles. A stress state of eccentric tension arises in the notch area. The loading is carried out before the formation and cracking of the notch tip. When loading, the force is recorded and judged by the viscosity of the destruction of the material,

Example. Samples of an apyuminium alloy B93 pch thick B 25 mm with dimensions ratios indicated in the claims were tested. Samples from the workpiece with the orientation of the DP, where D is the fractional load application, P is the transverse propagation of the crack. The test results were compared with the test results of a prototype sample with a 25x25 mm square section and a working section length equal to two sample widths (i.e., 50 mm)

Claims (1)

The use of this sample made it possible to significantly improve the accuracy of determining the fracture toughness and expand the range of measured values from 30 to 50 MPa-m /. Invention Formula Chevron notched dual-console prismatic specimen for determining the fracture toughness of materials under off-center stretching, characterized in that, with a precision chain for determining the fracture toughness and increasing its measurement range for alcuminic alloys, the sample height H is selected from the condition of 0.832 W and 0.848 B, where B is the width of the sample console, the length W of the working part of the sample is selected from the condition 1.072 V) 5 W 1.088 V, and the width of the notch cS is selected from the condition 0.056 E, 0.072 V, SudA § - FIG 3 CPU g in to Fy