Interfaces

Definition

Several interfaces are available in RADIOSS, this section deals with contact interfaces only. Each interface is distinguished with a type number. Interface type 2 is a kinematic condition used to connect two Lagrange meshes and is not detailed in this section (refer to Kinematic Conditions). A brief overview of the contact interfaces are shown below in Table 5.1.

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 type 7, 10 and 11) or via the search of the nearest node (other interface types). The nearest node search is done with a cheap, but limited algorithm (interface type 3, 5 and 6).

Interface types 3, 5 and 6 also have some limitations concerning the choice between the segments connected to the nearest node. Normal orientation is one limitation for these interfaces.

Interface type 23 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 types 20 and 24 use constant penalty stiffness and therefore the time step is not affected.

Heat friction could be computed using interface types 7 and 21.

Type	Description	Application	Contact Treatment
1 / 9	ALE / LAG with sliding	Fluid-structure interaction	Master-Slave
2	Tied interface	Change of mesh density (solid)	Master-Slave or LM
3 & 5	Contact impact between two parts	Use of Type 7 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 Type 7, 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 Type 7 and Type 11	Solid contact impact at all speeds and For beams, bars or springs	Penalty
20	General single surface or surface to surface contact interface	This contact interface can replace interface type 3, 5, 7, 11 or 19	Penalty stiffness is constant and therefore the time step is not affected
21	Specific interface between a non-deformable master surface and a slave surface	For stamping	Master-Slave
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 type 3, 5, 7, or 20	Penalty stiffness is constant and therefore the time step is not affected

Table 5.1: Interfaces in RADIOSS