Numerical and experimental study on the effects of anisotropy in the tube hydroforming process
Abstract:
The forming of metal tube is one of the traditional processes in producing various industrial products. Therefore, it is important to study the effect of various parameters on formibility in order to improve the quality and increase the production rate and productivity. In this thesis, the effect of anisotropy on the formation of copper C12200 alloy tube has been investigated. The mechanical properties of copper tubes were extracted experimentally using simple tensile test and plane strain tensile. Also, ABAQUS finite element software was used to simulate and investigate the formibility of the alloys. The Marciniak–Kuczynski model was chosen for the prediction of necking in material. Two types of Hill yield criteria and the BBC2003 yield criteria were also used separately to predict the behavior of the material. In order to apply the anisotropy behavior of the metal tube, the BBC2003 yield criteria developed under the VUMAT subrotine. The imperfection factor of the Marciniak–Kuczynski model was extracted using the experimental results of uniaxial tensile test and finite element simulation. The most common form of determination of the formibility is the use of the forming limit diagram. In order to investigate the effect of coefficient anisotropy, imperfection factor, equivalent stress and strain hardening index on copper formibility, the copper forming limit diagram was used. Simulation results show that although anisotropy coefficients increment, has no significant effect on the strain-base forming limit curve, but leads to an increase in the stress-based forming limit curve. In addition, increase in imperfectiom factor, equivalent stress and strain hardening index lead to increase in limit strain. The results of BBC2003 yield criterion have more consistent with experimental results than Hill 48 yield criteria.