Influence of Contact Formulation while Solving a Linear Model

Question: Why the linear solution results differ with number of substeps? There is no material non-linearity, large deflection is off and all contacts are bonded. 

Answer: There are few contacts with MPC formulation and few contacts with Augmented Lagrange. MPC is purely linear. But for Augmented Lagrange, Small sliding was turned OFF manually. This leads to a finite sliding and the Newton-Raphson iteration is triggered.  

 For finite sliding the following is true - "each contact detection point can interact with different target elements, depending on the contact status (open, closed, or sliding). The program re-forms nodal connectivity of the contact element based on the current configuration at each equilibrium iteration." 

 Therefore it will make a difference if you solve it in single substep or multiple substeps. 

 For additional information, you may want to refer to the Ansys Help documentation here – 3.9.7 Selecting a Sliding Behavior