Rate sensitive continuum damage models and mesh dependence in finite element analyses

Area of Science:

• Computational mechanics
• Materials science
• Finite element analysis

Background:

• The Johnson-Cook (JC) dynamic failure model is widely used in simulations.
• Local damage models can lead to mesh dependence, affecting simulation accuracy.
• Understanding and quantifying mesh dependence is crucial for reliable simulations.

Purpose of the Study:

• To investigate the extent of pathological mesh dependence in the JC dynamic failure model.
• To compare the mesh dependence of the JC model with a continuum damage model.
• To analyze the influence of different damage evolution mechanisms on mesh sensitivity.

Main Methods:

• Orthogonal machining simulations were performed.
• Two damage models were compared: JC dynamic failure and a continuum damage model.
• 2D shear tests were conducted using various finite element (FE) mesh representations.
• Realistic pearlite material properties were utilized.

Main Results:

• Significant element size dependence was observed for the JC dynamic failure model.
• Both the JC model and the continuum damage model exhibited similar degrees of mesh dependence.
• Viscous regularization effects were found to be absent in the current study.
• Damage evolution significantly impacts material response in both models.

Conclusions:

• Mesh dependence is a significant issue in the JC dynamic failure model, stemming from local damage models.
• The choice between the JC dynamic failure model and a continuum damage model does not substantially alter mesh dependence for pearlite.
• Further research may be needed to develop mesh-independent damage models for dynamic failure simulations.