A Lode-dependent enhanced Lemaitre model for ductile fracture prediction at low stress triaxiality

• We propose a Lode-dependent enhanced Lemaitre (LEL) model for fracture prediction.
• Mechanical tests at different loading configurations are performed for 2 materials.
• A J2J2–J2J2 plasticity criterion is proposed and identified by inverse analysis.
• The LEL model predicts accurately fracture for the tests performed on 2 materials.

The present paper deals with a modification of the stress triaxiality-based Lemaitre damage model to predict the ductile fracture at low stress triaxiality and shear-dominated loadings. The influence of the third stress invariant on damage evolution is introduced through the Lode parameter to form the Lode-dependent Enhanced Lemaitre (LEL) model. The enhanced model is then employed to predict fracture at different loading configurations and for two materials. For each material, the hardening law is first identified using both J2J2 and J2J2–J3J3 plasticity criteria depending on material. A methodology to obtain the damage model parameters is then presented and applied to two different materials. Good agreement between the experimental and numerical results is obtained, which shows the interest of the proposed model to predict the ductile fracture for various loading configurations at both low and high stress triaxialities.