The deformed geometry functionality can be also used to set up an incremental deformation of a structure. This can be achieved by using the Elastic Predeformation node in the Solid Mechanics interface. This can significantly speed up computations is case of large deformations.

One can use upd to define the displacement of the material frame with respect to the geometry frame, and take u as an update solution of the equations solved by the Solid Mechanics interface on the material frame. (The corresponding deformation gradient F connects the material and spatial frames.) Note that the virtual work on such a displacement update is done by the total stress, and to get the correct stress, one can use as Fpd the deformation gradient connecting the geometry and material frames, and then set the elastic deformation gradient to

Alternatively, a time dependent study can be used. In this situation, the above formula will be applied during each time step to recompute upd before the step, using the stored previous solution, while u will represent a displacement increment computed during the time step. In addition, the density is updated as ρ0/Jpd where

Again, Fpd is the deformation gradient connecting the geometry and material frames, and it will be updated before each time step or parameter sweep value.

which together with Equation 3-7 gives

Note that both Fel and Fpl represent the total deformations of their corresponding types, while Fpd is the total (elastic and plastic) deformation gradient from the previous update.