In this blog, we will look at the sophisticated contact discretization method offered by Abaqus: surface-to-surface contact.
The following example highlights the negative effects of poor mesh density selection for contacting parts.
Figure 1: example model
One method for reducing the negative effects of “incorrect” master-slave relationships is to use the surface-to-surface contact discretization method, illustrated in Figure 2.
Figure 2: surface-to-surface, master surface is smaller and has higher element density than the slave.
The surface-to-surface contact discretization method uses the average slave node positions to enforce each contact. Each contact constraint is biased towards the closest slave node but will also consider other slave node positions. Figure 2 shows that this method can help to mitigate some issues associated with the node-to-surface discretization method. Figure 3 shows the same analysis but with the “correct” master-slave relationship.
Figure 3: surface-to-surface, the slave surface is smaller and has higher element density than the master. Edge loads not seen in Figure 1 are now apparent.
Figure 3 shows that the surface-to-surface method still benefits from the correct master-slave relationship, as high stress regions, in the form of edge loads, are now apparent at the edges of Part Two. These edge loads were not present in Figure 2, as in that configuration the master nodes at the corners could pass through the coarse slave mesh. Additionally, the correct master-slave relationship is likely to lead to a more efficient analysis, as a coarse slave can lead to longer processing times.