Highlights
Extended thermal capabilities represent certainly a big step forward for hot-forming simulation capabilities, as well as general applications. Thermal expansion and heat transfer capabilities have been generalized to all materials and element types (solids and shells).
Controlling manufacturing process is sometimes crucial for the performance of a component. Damage evaluation, together with thinning and residual stress and strain is critical for an accurate description of the initial state of a component that after being formed, should undergo a set of tests. Damage initiation is now extended to shells. Damage can also be output into animation files, and might be helpful for failure risk prediction.
| • | Generalization of thermal expansion to: |
| - | all small strain formulations |
| - | all element types (solids and shells) |
| • | Improved results accuracy for thermal expansion. |
| • | Radiation (/INTER/TYPE7): possibility to compute the radiative exchange between two parts which are not in contact. |
| • | Thermal conductivity (/INTER/TYPE7): depending on contact pressure. |
| • | Thermal time-step: usually thermal time step is several orders of magnitude larger than mechanical time-step. For example, for quenching simulations, thermal time-step might speed-up the solution by a factor 1000x about. |
| • | Heat output in time history: new option QFRIC in /TH/INTER outputs thermal energy generated from contact friction. |
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| • | Manufacturing process may severely affect material properties; evaluation of damage due to manufacturing is critical for the performance of the components in real tests. |
| • | Damage now can be output (*.sta file) and initialized both for shells and solids. |
| • | Damage can also be visualized in *.anim file (/ANIM/BRICK/DAMA and /ANIM/SHELL/DAMA). |
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| • | Metals: Input yield stress curve (Iyield0=1) in orthotropic direction is possible (option Iyield stress flag in /MAT/LAW32, /MAT/LAW43 and /MAT/LAW73). |
| • | Failure: NXT failure criterion is an extension of /FAIL/FLD, where the failure is checked against the stress (in FLD the failure is checked in the strain domain). NXT main advantage v. FLD is that failure is stress and strain history path independent. Output at each integration point is available. |
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Force on tools can be predicted with higher accuracy by taking into account the blank bending force due to drawbeads.
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In forming simulations the time in animation file is not relevant, while some key information (like the tool displacement or distance from the blank) are not plotted. Now animation file titles can be defined in Engine file (1 title per animation file).
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Thermics
| • | LAW80: possible segmentation violation error: |
| - | when using table input + single precision |
| • | LAW80: possible wrong plastic strain output. |
| • | Nodal temperature may depend on small strain formulation used. |
| • | Different nodal temperature results between fine mesh and adaptive mesh. |
| • | Possible incorrect energy balance (99% Energy Error). |
| • | Possible incorrect volumetric expansion. |
| • | Thermal conduction might happen in all /INTER/TYPE7 contact interfaces defined in a model, even if requested only in a single one. |
| • | Incorrect thermal expansion results for solid model if full geometric non-linearities formulation (Ismstr=2, 4) is used. |
General
| • | Possible NaN energy output per integration point (NPT > 5 in shell property). |
| • | Possible Starter Error if STATE/ADMESH and SH3N are used simultaneously. |
| • | Using STATE/THICK + Adaptive mesh, elements are written several times in .sta file. |
| • | Starter errors out in Adaptive Meshing if Node ID and shell ID are > 900000000. |
| • | Possible ERROR 760 during spring-back phase. |
| • | For /FAIL/NXT criterion, results sigma1/h and sigma2/h could be output in all layers, in upper/lower/membrane layer or in N layers. |
| • | Starter issues a warning – instead of error - message if *.sta file includes elements which might have been removed from the Starter (due to trimming). |
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