A new elastoplastic-damage model with the correction of stress triaxiality and Lode angle

TL;DR

This paper introduces a novel elastoplastic-damage model that incorporates stress triaxiality and Lode angle effects to better predict metal behavior under complex loading histories, validated with aluminium experiments.

Contribution

It develops a fully coupled ductile damage model considering stress state corrections via triaxiality and Lode angle, improving accuracy over classic models.

Findings

Enhanced prediction of damage evolution in metals.

Validation with aluminium 2024-T351 experiments.

Improved modeling of stress history effects.

Abstract

The classic elastoplastic-damage constitutive model neglects the effects of loading histories. But in fact, more and more experiments results show that the states of stress can significantly affect the response of metals not only in the plasticity but also in the damage evolution. This paper presents an elasto-plastic fully coupled ductile damage constitutive model which considers the corrections of the metal plasticity and the damage evolution through the states of stress. The stress triaxiality and the Lode angle are frequently used to characterize the state of stress. The correction of metal plasticity is achieved by applying a new flow stress model associated with the stress triaxiality and Lode angle. A stress state parameter which depends on the function of stress triaxiality and Lode angle is also proposed. In order to calibrate the damage evolution, the stress state parameter is introduced into the Chaboche damage model. The experiment results of aluminium 2024-T351 are used to validate the proposed constitutive model.