PRELIMINARY PROBE ON THE APPLICATION OF STRESS TRIAXIALITY IN SPALLING FIELDS

We investigate the necessity and possibility about the application of the stress triaxiality used for the analysis of spalling fields. Combining with the size-independence of a cell model, the numerical simulation method, employed for the implementation of void growth under a high stain rate and high stress triaxiality, is discussed. On this basis, we perform the simulation of void growth under different stress triaxiality in the axial symmetry cell. The calculation results indicate that the macroscopic equivalent stress vs. equivalent strain relation and void volume fraction vs. spherical stress relation are not unique correspondence, but depend on the stress triaxiality. Therefore, the damage constitutive or equation of states in specific stress states based on the strain equivalence principle could not be appropriate for applying to other stress states, e.g. the obtained damage constitutive and equation of states by acting on the spherical stress in the hollow sphere cell model cannot be described for the non-spherical stress states.