Influence of Contact Formulation While Solving a Linear Model — Lesson 7

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

There are few contacts with Multi-Point Constraint(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