| Summary: | Different dimensions of tensile test specimen can be used for qualification of welding procedure according to the existing standard. However, they are found to be dissimilar in tensile properties. In this study, the tensile properties of TIG welded 2219-T8 aluminum alloy joints were tested with different tensile specimen sizes. The welding residual stress releasing, specimen size effect, as well as fracture criteria were taken into account by using a sequential “welding - cutting - tensile” finite element simulating method. Results indicated that the degree of welding residual stress releasing decreased with the increasing of specimen width. For specimens with 250 mm width, over 80% of the residual stresses were kept. Tensile testing result showed that the tensile strength and elongation of joint decreased when the specimen width increased. The differences in tensile properties were proved to result from the size distinctions, rather than residual stress releasing, because the stress triaxialities were different in the specimens with different sizes. This phenomenon was precisely simulated by using the Johnson–Cook fracture criterion. Eventually, the constitutive equations of Johnson–Cook model were established based on the experimental tensile strengths to describe the tensile behaviors of 2219 aluminum alloy joints.
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