Testing device for determining tensile constitutive relation and elastic modulus by bilinear splitting method

Abstract

The invention discloses a testing device for determining tensile constitutive relation and elastic modulus by a bilinear splitting method. The testing device comprises two hump loading heads which are respectively arranged on the upper side and the lower side of a rectangular test piece and used for applying loads to the rectangular test piece, and a strain sensor or a displacement sensor fixed in a stable tensile stress area in the middle of the rectangular test piece. The testing device for determining tensile constitutive relation and elastic modulus by the bilinear splitting method disclosed by the invention avoids the testing deviation caused by the machining precision of a cylindrical or disk test piece by using a conventional splitting method, and can obtain the stable tensile stress area and determine the tensile strain in the area, stress-strain relation in a tensile state is established by a testing method, and then the elastic modulus of the test piece in the tensile state is determined, thereby filling up a blank that the testing method cannot accurately obtain the tensile constitutive relation of a quasi-brittle material.

Description

technical field [0001] The invention discloses a measuring device, in particular to a measuring device for testing the tensile constitutive relationship and elastic modulus of quasi-brittle materials such as concrete or rocks. Background technique [0002] The tensile strength of quasi-brittle materials such as concrete and rocks can be determined by test methods, including direct tension method and split method (including cylinder split method and Brazilian disc method). When the specimen is subjected to a pair of splitting concentrated loads, uniform tensile stress is generated in the direction perpendicular to the loading direction according to the principle of elastic mechanics, and the corresponding load when the member is split into two halves can be converted into the tensile strength of the material; directly Due to the problem of centering deviation, the measured data are very discrete in the tensile method, and the true tensile stress in the component cannot be acc...

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Problems solved by technology

When the specimen is subjected to a pair of splitting concentrated loads, uniform tensile stress is generated in the direction perpendicular to the loading direction according to the principle of elastic mechanics, and the corresponding load when the member is split into two halves can be converted into the tensile strength of the material; directly Due to the centering deviation problem, the tension method makes the measured data very discrete, and the real tensile stress in the component cannot be accurately obtained; the split method mostly uses a cylindrical or disc structure, and the machining accuracy of the disc has a great influence on the test results; and The distribution of tensile stress in the middle of the disk perpendicular to the loading direction is extremely uneven, and the stress decays rapidly with the increase of the distance from the center position. Generally, it is only used to determine the ultimate tensile strength, and cannot be used to determine the corresponding relationship between tensile stress and strain. , and the elastic modulus in the stretched state cannot be accurately determined

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