Establishment of Stress-strain Relationships of Tailor-welded Tubes via DIC Method Based on Uniaxial Tensile Tests

摘要

Tailor-welded tubes are widely applied to tube hydroforming field due to their advantages of low cost, reduction in part weight and flexibility in mass production. It is necessary to determine the stress-strain relationships of tailor-welded tubes to study deformation behaviors of tubes and simulate deformation tests of tubes. A method via digital image correlation (DIC) method based on uniaxial tensile test (UTT) was proposed in this paper. Through this method, material parameters are got based on full-field strain condition. Material parameters of tailor-welded tubes were obtained through three methods, i.e. the proposed method, the method based on UTT and the iso-strain method based on a rule of mixtures, respectively. UTT was simulated to analyze the reliability of those three methods. So the load-displacement curves and maximal loads obtained from simulations were compared with those obtained from UTTs. The result shows that: On determining material parameters of the weld, the proposed method is more reliable than the iso-strain method based on a rule of mixtures; the load-displacement curve and maximal load both obtained from the proposed method are found to match better to those obtained from test than those obtained from the method based on UTT.