Several interfaces are available in Radioss, this section deals with contact interfaces only. Each interface is distinguished with a type number.

Interface TYPE2 is a kinematic condition used to connect two Lagrange meshes and is not detailed in this section (refer to Kinematic Constraints). A brief overview of the contact interfaces are shown in Table 1.

Each of these interfaces was developed for a specific application field, but this field is not the only choice criteria. Some limitations of the different algorithms used in each interface can also determine your choice.

The algorithm limitations mainly concern the search of the impacted segment. This search can be done directly (interface TYPE7, TYPE10 and TYPE11) or via the search of the nearest node (other interface types). The nearest node search is done with a cheap, but limited algorithm (interface TYPE3, TYPE5 and TYPE6).

Interface TYPE3, TYPE5 and TYPE6 also have some limitations concerning the choice between the segments connected to the nearest node. Normal orientation is one limitation for these interfaces.

Interface TYPE23 defines a contact interface for airbag fabrics. This is a soft penalty contact which can deal with penetrations and intersections often coming in the folded airbag mesh.

Interface TYPE24 use constant penalty stiffness and therefore the time step is not affected.

Heat friction could be computed using interface TYPE7 and TYPE21.
Table 1. Interfaces in Radioss
Type Description Application Contact Treatment
1 / 9 ALE/LAG with sliding Fluid-structure interaction Main-Secondary
2 Tied interface Change of mesh density (solid) Main-Secondary or LM
3 & 5 Contact impact between two parts Use of TYPE7 is recommended Penalty
6 Contact impact between two rigid bodies User-defined contacts Penalty
7 General purpose contact impact between two parts Solid contact impact at all speeds Penalty or LM
8 Drawbead contact Stamping applications Penalty
10 Like TYPE7, but tied contact Special purpose interface Penalty
11 Impact between two lines For beams, bars or springs Penalty
12 Fluid / fluid contact Fluid to fluid contact Penalty
16 & 17 Contact between nodes to quadratic shape solids and solid-shells or between quadratic shapes Meshes with 8-node or 16-node thick-shell or 20 bricks LM
18 CEL Lagrange / Euler interface Fluid-structure interactions Penalty
19 Combination of interface TYPE7 and TYPE11 Solid contact impact at all speeds and For beams, bars or springs Penalty
21 Specific interface between a non-deformable main surface and a secondary surface For stamping Main-Secondary
23 Soft penalty contact For airbag Soft penalty
24 General contact interface, optional single surface or surface to surface or nodes to surface contacts This contact interface can replace interface TYPE3, 5, 7 Penalty stiffness is constant and; therefore, the time step is not affected