Numerical simulation method for thermal composite forming of titanium alloy

Abstract

The invention provides a numerical simulation method for thermal composite forming of titanium alloy. The numerical simulation method includes the steps of 1), subjecting the titanium alloy to a thermal unidirectional tensile test in a material testing machine; 2), drawing titanium alloy constitutive curves and identifying material parameters; 3), inputting the parameters determined in the step 2) into an analysis module on the basis of finite element software and analyzing the thermal tensile deformation process I; 4), performing material thermal stress relaxation test on the material testing machine; 5), drawing titanium alloy stress relaxation curves; 6), selecting proper creep deformation constitutive function and determining relaxation parameters of materials; 7), substituting the relaxation parameters determined in the step 6) into a creep deformation analysis module on the basis of taking simulation results in the step 3) as an initial state of the relaxation process II; 8), performing springback analysis by taking relaxation simulation data as the initial state of springback unloading. The results show that the titanium alloy subjected to stress relaxation is lowered in stress and reduced in springback, and parts are high in forming accuracy.

Description

technical field [0001] The invention relates to a numerical simulation method for thermal composite forming of a titanium alloy, in particular to numerical simulation and springback calculation of two processes of thermal forming and creep relaxation of a titanium alloy material, and belongs to the technical field of thermal processing of materials. Background technique [0002] Titanium alloy materials have many advantages such as high specific strength, low density, high strength, high temperature resistance, corrosion resistance, and no galvanic corrosion with composite materials, so they are increasingly used in the aerospace industry. However, due to the close-packed hexagonal crystal structure of titanium alloy, there are few slip systems, the plastic formability at room temperature is very poor, and it is difficult to process by cold forming, which greatly limits its application in structure. In this regard, most titanium alloys are manufactured by hot forming. Titan...

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Problems solved by technology

However, due to the complexity of creep, especially stress relaxation, its time-dependent, instantaneous micro-variation, and highly nonlinear characteristics, the study of creep relaxation has become extremely difficult; in addition, due to the high cost of high-temperature tests on titanium alloys characteristics, resulting in a greatly enhanced reliance on numerical simulations

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