A measuring device capable of realizing real-time measurement of sample cross-sectional geometric dimensions and its application

Abstract

The invention discloses a measuring device which can be used for a tensile test machine and can carry out real-time measuring on the geometric dimensioning of a cross section in the sample tensile testing process and application of the measuring device. A true stress-strain curve of a material to be tested is acquired, and the tensile mechanical behavior of the material is scientifically and effectively analyzed. The measuring device is composed of a movable platform, a camera I, a camera II, a support, a drive device and the like. The measuring device can be directly installed on an ordinary tensile test machine in a modularization mode and can measure the real-time geometric dimensioning of the cross section of a sample in the tensile process, and the measuring device is ingenious in structure, simple and practical.

Description

technical field [0001] The invention relates to a measurement device for real-time measurement of the cross-sectional geometric dimensions of various materials under different tensile states and the application thereof. Background technique [0002] When the existing tensile testing machine tests the mechanical tensile properties of material samples, the initial cross-sectional area of ​​the sample is usually used to calculate the internal stress of the material, and the obtained tensile test results are engineering stress-strain curves. Although there are measurement errors in this test processing method, it is generally acceptable for test materials with relatively small elongation. In recent years, with the continuous expansion of research and development and the deepening of research on engineering application materials, it has been found that the application of engineering stress-strain curves is relatively unscientific in explaining the mechanical behavior mechanism of...

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Problems solved by technology

[0004] But these inventions in the above table still have limitations:

[0007] However, many materials with high elasticity, superplasticity and large elongation have a large size change in the tensile direction during the tensile test, resulting in a large change in the cross-sectional area of ​​the sample perpendicular to the tensile direction. In this state, the deviation between the engineering stress and the true stress is very large (some up to tens of times), and the use of engineering stress cannot represent the true stress-strain behavior of these materials in this tensile state, so for a long time The widely used engineering stress-strain curves cannot scientifically and truly characterize the mechanical properties and deformation mechanisms of these materials