Identification of Constitutive Parameters of Laser Welded Aluminum Alloy Using Digital Image Correlation

Abstract

An inversion identification method of local wise elastic-plastic constitutive parameters for laser welding of aluminum alloys 6061 was proposed based on full-field optical measurement data using digital image correlation (DIC). Three regions, fusion zone, heat affected zone and base zone of the laser welded joint were distinguished by means of microstructure optical observation and micrometer hardness measurement. The stress data was obtained by the laser welded specimen under uniaxial tensile test, meanwhile, the local strain data of the laser welded specimen was measured by the DIC technique, so the stress-strain relationship for different local regions was established. At last, the constitutive parameters of Ramberg-Osgood model were identified by least-square fitting to the experimental stress-strain data. Experimental results reveal that the mechanical properties for the local zones of welded joint are obviously weakened, which are consistent with the hardness measurement.