Metal plate two-way stretching large-deformation thickened test piece

Abstract

The invention discloses a metal plate two-way stretching large-deformation thickened test piece. The metal plate two-way stretching large-deformation thickened test piece is of a cross structure divided into four cross arms and a central crossed area. The four cross arms are equal in length and width, thickening plates are symmetrically arranged on the upper side and the lower side of each arm, and thus a three-layer composite plate structure is formed. According to the metal plate two-way stretching large-deformation thickened test piece, the feature of a test area material is not changed, the load transmitting capability of the cross arms is enlarged, stress concentration in a transition area between every two adjacent cross arms is relieved, large test piece central area deformation is obtained, and thus the practicability of stress strain of the test material in a two-way stretching test is improved.

Description

technical field [0001] The invention discloses a metal plate biaxially stretched large deformation and thickened test piece, specifically a plate biaxially stretched test piece, belonging to the technical field of sheet metal plastic forming. Background technique: [0002] In the field of sheet metal plastic forming, plastic yielding behavior has always been an important research focus, especially with the continuous introduction of many new processes, new structures, new material sheets and some new forming processes, the yield behavior (including initial yield and subsequent Yield) is the key to get accurate results in theoretical analysis and finite element analysis. [0003] The traditional test methods used for the research of yielding behavior have certain limitations. The application of thin-walled pipes under the action of axial load and internal pressure, axial load and torsional load can realize different strain paths, but there is a certain gap in performance bet...

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Problems solved by technology

[0007] 2) The measurement and calculation methods of stress and strain in the central area of ​​the specimen, especially the determination of the stress in the central area;

[0012] Among these different types of cross-shaped specimens, the slit / groove type on the arm has been studied the most. The advantage is that the slit / groove on the arm can greatly reduce or even eliminate the shear stress in the central area, so that the stress in the central deformation area The principal axis coincides with the tensile direction, so that it is convenient to measure and calculate the stress value in the central area; the disadvantage is that this kind of test piece is only suitable for reinforced materials, and the deformation of the central area will not be large, because only when the seam / groove area After the metal has entered the strengthening stage, the stress in the central test area can reach a sufficiently high level, and the cross arm often breaks before the central area

The thinned test piece in the central area can cause a large deformation in the central area, but the change of the original properties of the material after the metal peeling needs to be considered when processing this test piece, and the first failure at the boundary between the central area and the thinned area will hide some Intrinsic properties of materials

Considering the inhomogeneity of the actual microstructure and the inhomogeneity of the thickness distribution of the steel plate with rough surface, the thinned cross tensile specimen in the central area is not suitable for the study of the micro- or macro-mechanical property changes induced by large deformation.

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