With Calculate on Deformed Geometry checked, the deformed geometry is re-sampled, and this geometry is used for the calculations in the next step. With this method, it is possible to detect new object contacts during deformation and e.g., to observe the effect of stiffening during compression. Calculate on Deformed Geometry can only be used without geometric nonlinearity.

A resampling step is done if the conditions defined under Geometry Update are met. It is important to choose these settings appropriately for the current geometry and deformation steps: With each resampling step, discretization errors occur, and these errors accumulate if too many resampling steps are done. Therefore, the resampling should only be done after a significant change in the geometry size. This can be achieved by choosing the mode Size Control for Geometry Update.

• Off: The deformation is always calculated relatively to the original geometry

• On:  If the conditions defined under Geometry Update are met, the deformed geometry is calculated, and the deformation is calculated relative to the previous geometry. In the figure below, the behavior of the setting All for Geometry Update is shown.

Keep Volume Fraction of Deformed Geometry

If Keep Volume Fraction of Deformed Geometry is checked, the accurate volume fraction information for each material ID after the deformation is stored and updated in memory. Refer to Resampling for further information about the volume fractions and how they are further processed to the final result. This needs more memory but leads to a more accurate geometry deformation if many (small steps) are computed. Without this information, the volume fractions are converted into a structure in each deformation step and the volume fraction gets lost.

Geometry Update

Under Geometry Update, it can be selected when the next simulation step is computed on the newly deformed geometry, or if it is computed based on the existing geometry.

Use the mode Size Control for the Geometry Update when using Calculate on Deformed Geometry. With this mode, the size of the deformation is checked after each step.

Only if the deformation is larger than the given threshold, Calculate on Deformed Geometry is used for this step. Otherwise, the step is done without Calculate on Deformed Geometry. We strongly recommend using this mode for simulations of this type.

• All – The geometry is updated in every step
  
• Step Control – Choose how often the geometry is updated with Update Geometry Each n-th Step.
  
• Size Control – If the geometry is updated or not depends on the change of the domain size. If the size change for one domain side is larger than the value defined for Geometry Change / (%), the geometry is updated.