Hi my Friends,
I am doing abaqus run for a copper specimen under hydrostatic pressure. The magnetude of pressure is in order of several Giga Pascals. In my material definition, I have defined stress-strain flow up to strain of 0.4. But as you can see in attached photo, some elements show very large deformation (considerably larger than 0.4). Knowing that I have not defined stress strain behaviour for srain greater than 0.4, how this can be occure? Unfortunately, niether adaptive meshing nor element deletation were not eliminate this issue!!
Best Thanks
If you stop your hardening xurve at 0.4, Abaqus will assume ideally plastic behaviour beyond that point. You may simply extend your stress-strain curve by extrapolating.
If you run under large hydrostatic pressures, plasticity calculations may become problematic because plastic deformation is volume-conserving. If you are using abaqus/standard, you can switch to hybrid elements; that will avoid these problems.
Furthermore, you should check for hourglassing if you use reduced integration elements - these elements are very sensitive to hourglassing problems.
If you stop your hardening xurve at 0.4, Abaqus will assume ideally plastic behaviour beyond that point. You may simply extend your stress-strain curve by extrapolating.
If you run under large hydrostatic pressures, plasticity calculations may become problematic because plastic deformation is volume-conserving. If you are using abaqus/standard, you can switch to hybrid elements; that will avoid these problems.
Furthermore, you should check for hourglassing if you use reduced integration elements - these elements are very sensitive to hourglassing problems.
As above researcer mentioned, key is the range of stress-strain curve( >=0.4). Beyond that point(0.4), as it stands, excessive stress may be computed, resulting in large deformation.
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