Method for determining thin plate reverse loading Bauschinger effect

Abstract

The invention discloses a method for determining thin plate reverse loading Bauschinger effect, and belongs to the field of thin plate stamping technology. The method comprises the following steps: 1) prestretching a to-be measured thin plate, unloading the prestretching force, then bending the thin plate, measuring deformation angle Z* after the thin plate rebounds; 2) measuring a series of the deformation angles Z* after the thin plate rebounds; 3) constructing a parameter model of the material of the to-be measured thin plate, endowing an initial value, and analog computing the thin plate rebounding angle to obtain a series of the deformation angles Z after the thin plate rebounds, comparing with the test result in step 2) till the difference of the two deformation angles reaches a preset threshold, and outputting a material parameter A which is obtained by calculating at the same time; and 4) carrying out finite element simulation by using the material parameter A to obtain a Bauschinger effect curve of the thin plate. The test apparatus and the data processing method are simple, mechanical testing data in larger strain can be obtained, influence factors are less and parameters are accurate.

Description

technical field [0001] The invention belongs to the technical field of sheet stamping, and in particular relates to a method for measuring the Bauschinger effect of reverse loading of a sheet. Background technique [0002] During plastic processing of metals, forward loading induces plastic strain strengthening, resulting in plastic strain softening (lower yield limit) of the metal material during subsequent reverse loading. This phenomenon was discovered by J. Bauschinger in 1886 in experiments on the mechanical properties of metal materials, and it is called the Bauschinger effect. [0003] Springback is one of the most important and difficult to control defects in sheet metal stamping, and the constitutive model of sheet is the key to high-precision prediction of springback by finite element method. At present, the constitutive model is insufficient to describe the mechanical properties of thin plates under variable path loading, which is the bottleneck that hinders the ...

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Problems solved by technology

In the cyclic simple shear test, the obtained stress and strain are not uniform, the stress is in a complex state, and when the strain is large, the edge effect is very serious

In the tension-compression test, the thin plate is very easy to be unstable when co

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