Experimental measurement method for uniaxial tension of hydrogel materials based on back-shaped specimens

Abstract

The invention discloses a uniaxial tensile test measurement method for a water gel material based on a test piece in the shape of Chinese character HUI. The uniaxial tensile test measurement method comprises the following steps: (1) preparing a water gel test piece in the shape of Chinese character HUI; (2) mounting the water gel test piece; (3) carrying out a tensile test, recording deformations of the middle parts of two parallel slender column bodies, namely positions away from the end parts of the column bodies, of the test piece by using a digital image related method in a test process, recording a load reading on a test machine, and obtaining a load-displacement curve of the PVA water gel material in a quasi-static uniaxial tensile test after the test according to test piece strain obtained by the digital image related method and a load acquired on the test machine. According to the method, by the adoption of the test piece in the shape of Chinese character HUI, the problem of clamping of the water gel test piece on the test machine can be well solved, so that the uniaxial tensile test of the water gel material can be successfully carried out; the problem of stress concentration can be eliminated, so that breakage points of the test piece are uniformly distributed. Meanwhile, the deformation of the middle part of the test piece can be obtained by the digital image related method, so that test data of the water gel material in the uniaxial tensile test can be acquired more accurately.

Description

technical field [0001] The invention relates to the technical field of uniaxial tensile experiments of hydrogel test pieces, in particular to a method for measuring uniaxial tensile experiments of hydrogel materials based on back-shaped test pieces. Background technique [0002] Uniaxial tensile test is one of the traditional methods to test the mechanical properties of materials, which can obtain the mechanical properties of materials relatively simply and accurately. The uniaxial tensile test requires clamps to fix the specimen to the testing machine to apply the load. Generally speaking, the traditional fixture clamps both ends of the specimen, and uses the friction force generated by compression to prevent the specimen from slipping, so that the end of the specimen follows the fixture to produce axial displacement without relative sliding. Since the end of the specimen is subjected to the transverse load imposed by the fixture in addition to the axial load, the end of t...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the difficulty of the uniaxial tensile test of soft materials represented by hydrogel, and provide a method for measuring the uniaxial tensile test of hydrogel materials based on back-type test pieces. The piece can well solve the clamping problem of the hydrogel specimen on the testing machine, so that the uniaxial tensile test of the hydrogel material can be carried out smoothly, and the problem of stress concentration is eliminated, and the fracture points of the specimen are evenly distributed

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