Determination method of normal anisotropy coefficient of pipe in any direction

Abstract

The invention discloses a determination method of a normal anisotropy coefficient of a pipe in any direction, and belongs to the field of pipe performance testing. The method comprises the steps of firstly establishing a relational expression between the normal anisotropy in any direction and a yield function, determining an undetermined coefficient of the yield function through a pipe bidirectional loading experimental method, and then determining the normal anisotropy coefficient of the pipe in any direction by substituting the established relational expression. The method ensures the accuracy and reliability of the normal anisotropy coefficient from three aspects, 1) blanks of related experiments are original tube blanks, the shape of the tube cannot be damaged, pre-deformation cannot be introduced, and the obtained experiment result can accurately reflect the plasticity of the tube; 2) an advanced yield function can be selected, and experimental data under different loading paths can be introduced simultaneously, so that the plastic flow characteristic of the pipe can be reflected more comprehensively; and 3) characteristic experiments for obtaining the same deformation in different directions are designed, and the accuracy and reliability of the coefficients of the shearing components can be ensured by repeatedly iterating the finite element analysis and the characteristicexperiments, thereby establishing an accurate and reliable yield function.

Description

technical field [0001] The invention belongs to the field of performance testing of pipes, and in particular relates to a method for determining the thickness anisotropy coefficient of pipes in any direction. Background technique [0002] Hollow integral components made of metal tubes are widely used in aerospace and automotive fields due to their structural weight reduction and excellent mechanical properties. This type of component is generally manufactured by internal high pressure forming technology. During internal high pressure forming, the pipe is deformed under the combined action of internal pressure and axial force, and the tube blank will experience a complex stress path from sealing, preforming to final forming. For complex components, it will even go through the process of loading-unloading-reloading. Once the loading path is unreasonable, defects such as wrinkles and cracks will appear. Therefore, it is very important to determine reasonable process parameters...

AI Technical Summary

Problems solved by technology

[0005] The present invention aims to solve the problem that the existing test methods cannot obtain the thickness anisotropy coefficient of extruded pipes in any direction, and proposes a method for determining the thickness anisotropy coefficient of pipes in any direction

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