Method for adopting bend test to test tensile elasticity modulus of material

Abstract

The invention discloses a method for adopting a bend test to test the tensile elasticity modulus of a material. A compressive elasticity modulus Ec of a material is supposed to be known, and the pure bending or transverse bending small transformation experiment is carried out in a linear elastic range of the material; axial strain values epsilon c and epsilon t of an optional position on upper and lower surfaces of the pure bending section of a sample or axial strain values epsilon c and epsilon t on the upper and lower edges of any cross section of the transverse bending section are measured in an experiment; a relation of the pressure-pulling elasticity modulus ratio and the pulling compressive strain ratio of the material is deduced through an equilibrium condition of a cross section, thereby determining the tensile elasticity modulus Et of the material according to the formulae shown in the specification. The method provided by the invention has the advantages that the theory is correct, a computing formula is concise, the parameter is easy to measure, and the tensile elasticity modulus of the material can be accurately measured.

Description

technical field [0001] The invention relates to a method for testing the tensile elastic modulus of a material, that is, a bending test is used to test the tensile elastic modulus of the material. Background technique [0002] Elastic modulus is one of the basic mechanical parameters of materials, and it is very important to accurately test the elastic modulus of materials. Many materials (such as rocks, concrete, FRP, plastics, ceramics, graphite, etc.) often exhibit significantly different elastic moduli in tension and compression. The compressive modulus of elasticity of a material is easily obtained by uniaxial compression deformation test. The best way to measure the tensile modulus of a material is of course a uniaxial tensile deformation test. In many cases, however, performing tensile deformation tests is difficult, especially for brittle materials. In May 2010, Chongqing University's master's degree thesis "Research on Different Moduli of Tension and Compression ...

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Problems solved by technology

However, this method has the following shortcomings: first, the displacement of the section where the measuring point is located needs to be tested in the experiment, and the test workload is relatively large; second, the bending moment on the cross section at different positions needs to be calculated; third, The formula for calculating the modulus of elasticity is relatively complicated (it is not given in this document, but it can be deduced from this document), which is inconvenient to use; The method of sticking the strain gauge to measure the line strain, the value of the cross-sectional bending moment corresponding to the length range of the strain gauge is not a constant

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