A Calculation and Detection Method of Strength and Index of Metal Material Based on Generalized Hosford Yield Function

Abstract

The invention discloses a calculation and detection method for the strength and index of metal materials based on the generalized Hosford yield function. The calculation method is as follows: firstly, the direction function is introduced, and the Hosford yield function is improved by Taylor expansion to the sixth-order tensor form; and then Based on the group theory and the objectivity of materials, considering the microstructure of the material, studying its plastic parameters, and establishing the Hosford cubic grain regularity under any stress state including the constant term, the quadratic term, the quaternary term and the sixth order term. Introduce the yield function of the sheet metal; then combine the plasticity theory to deduce the relationship between the yield strength of the metal sheet at different angles, the anisotropy index q value and the texture coefficient; finally, according to the texture coefficient of the metal sheet measured, the Yield strength and anisotropy index q value of orthogonal metal plates under different angles. The invention avoids the destructive test on the material, and provides a necessary theoretical basis for the study on the formability of the plate.

Description

technical field [0001] The invention belongs to the technical field of sheet metal forming and material processing, and relates to a method for calculating the yield strength and anisotropy index of sheet metal, specifically a method for establishing a new generalized Hosford orthogonal metal material yield function, and proposing a method for texture coefficient The invention relates to a method for calculating the yield strength and anisotropy index of a metal sheet, in particular to a method for detecting the strength and index of a metal material based on a generalized Hosford yield function. Background technique [0002] Metal sheet has the advantages of high strength, good elasticity, plasticity and plastic processing performance, strong corrosion resistance, good heat resistance and durability, and is widely used in many fields such as aerospace, automobile manufacturing, and mechanical design. The metal sheet is an aggregate of a large number of tiny crystal grains (...

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Problems solved by technology

However, since the metal sheet is relatively thin, it is difficult to accurately measure the strain in the thickness direction, and it is difficult to accurately obtain the anisotropy index q value of the sheet

[0004] Although Huang Mojia from the Engineering Mechanics Experimental Center of Nanchang University published a paper titled "General Hosford yield functions of forthorhombic materials" in the journal "ARCHIVE OFAP PLIEDNECHANICS", in which he proposed a generalized Hosford yield function including three principal stresses and principal stress directions. Yield function, but it can be seen from the literature that it fits the q value well when the plastic deformation of the orthogonal plate is deformed, but the error is large for the yield stress, and it is difficult to meet the accuracy requirements

Therefore, there is no better calculation formula for the material texture coefficient in the prior art

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