Establishment and verification of two-component ductile fracture criteria with high estimation accuracy

In the present work, two-component ductile fracture criteria with high estimation accuracy were established. They were formulated by using a weighted superposition of the existing ductile fracture criteria as basic components, which possessed the same form but different parameters. The flexibility of new criteria was greatly enhanced because of increased material constants. The micro-mechanism-inspired DF2012 criterion and its improved form of DF2014 criterion were chosen as the basic components, respectively. Based on the established criteria, the fracture surfaces of aluminum alloys 2024-T351 in various stress and strain spaces were constructed and compared with those constructed by the single-component criteria. The results showed that the two-component criteria have better prediction accuracy than the single-component counterparts, especially for the tests at high stress triaxiality region. Due to the shear-linking assumption, fracture strains constructed by the single-component DF2012 and DF2014 criteria at high stress triaxiality region inevitably carried large errors. However, these errors were largely reduced by the established two-component criteria. It indicates that the two-component criteria can overcome some inherent shortcomings of the single-component criteria, which is an effective solution to promote the fracture estimation accuracy.