Source model preparation
Special situations modeling:  Contacts

ProTOp can not handle models containing general contact situations. However, it contains special semi-contact elements that enable efficient handling of special contact situations, where the relative movement between contact regions is negligibly small. Typical situations that fulfil this criterion in linear stress analysis are pin connections with negligible rotation.

In order to engage the semi-contact elements, a devoted contact volume region has to be prepared in the model. This contact region has to be modeled as an interlayer with relative small thickness. Typically, one or two finite elements should be placed in the direction of the layer thickness. To declare this region as a contact region, the semi-plastic material model has to be assigned to corresponding finite elements.

NOTE. Contact regions are not optimized. In this view they are always treated as fixed regions.

The figure below shows an assembly of three volume regions:

The contacting regions (1 and 2) are joined by the interlayer contact region (3).

Figure. Example of a fixed holder (gray) and an optimization part (transparent blue), connected by a contact interlayer (red).

Note that the contact interlayer region must be the only connection between both connecting regions to model properly semi-contact behavior. In other words, regions 1 and 2 must have no common surfaces or edges. A detailed cross-section view of the presented example is shown in the figure below.

Figure. Cross-section and detailed view of connections between individual regions.

NOTE. The contact interlayer region must be the only connection between both connecting regions.

If a contact is modeled properly, this should be clearly visible when examining the optimized design. The figure below shows the optimal design of the presented example with a properly modeled contact.

Figure. A correctly modeled contact should be clearly reflected in the form of the optimal design.