• Path Controlled
  specify the mean strain in the geometry (for geometric linear experiments) or the mean displacement gradient in the geometry (for geometric nonlinear experiments) in the load direction.
• Force Controlled
  Specify the mean stress in the geometry (for geometric linear experiments) or the mean nominal stress in the geometry (for geometric nonlinear experiments) in the load direction. It is important to note that the mean stress is computed with respect to the complete geometry. If a structure consists of solids and pore space, this means that the average load on the solids is larger than the given mean stress, since the load in the pore space is zero.

Generally, Path controlled should be preferred over Force Controlled if possible. One of the challenges with Force Controlled is the fact that the Strain-Stress curves for plastic materials are often very flat: This means that a small change in stress can lead to a very large change in strain. On the other hand, a small change in strain leads to an even smaller change in stress. Therefore, the Path Controlled simulation is much easier to compute. For simulations with damage, Force controlled may be even impossible to solve (because the given stress might be higher than the maximal stress allowed by the material), while Path Controlled can always be solved (see also the load type recommendations).