Molecular dynamics simulations of void effect of the copper nanocubes under triaxial tensions

• The models under triaxial tension are simulated.
• The nanocubes with different void size percentages are investigated.
• We bring in some mechanical concepts for simulation.
• The yield stress reduce with void percentage increasing.
• We propose a modified damage tendency model in microcosm.

The isotropic copper nanocubes with different size cubic voids under triaxial tensions are investigated by the molecular dynamics method. For accuracy we present the hydrostatic stress, Mises stress, true stress, logarithmic strain and relationship between each other. In the simulation the number of model atoms is formulized and the hydrostatic stresses can replace triaxial stresses of model. We demonstrate that the yielding strengths will decrease with increase of void, particularly when the void percentage is reaching 0.2%. The models are breaking at 45 angle dislocation with tiny differences. Also, the Gurson model cannot well describe the trend of damage; instead the authors propose a modified model by relationship between Mises stress and hydrostatic stress.