Figure 18: Interface2dquad element with quadratic interpolation. Definition and node numbering convention
Interface elements represent a contact between two adjacent nodes. Interface material specific to interface element needs to be assigned - consult the matlibmanual for interface support.
Implementation of one dimensional (slip) interface element. This element can connect two separate nodes by specifying the one-dimensional slip law, that determines the force acting between these nodes depending on their relative displacement. This element can be applied in 1D, 2D, and 3D settings (default). The element features are summarized in Table 28.
| Keyword | Interface1d |
| Description | One dimensional (slip) interface element |
| Specific parameters | [refnode #(in)] [normal #(ra)] |
| Parameters | refnode: determines the reference node, which is used to specify a reference direction (the direction vector is obtained by subtracting the coordinates of the first node from the reference node). |
normal: The reference direction can be directly specified by the optional parameter normal. Although both refnode and normal are optional, at least one of them must be specified. |
|
| Unknowns | One, two, or three DOFs (u-displacement, v-displacement, w-displacement) are required in each node, according to element mode (determined from domain type). |
| Approximation | - |
| Integration | - |
| Features | - |
| CS properties | - |
| Loads | - |
| Nlgeo | 0 |
| Status | Reliable |
| Note | Element requires material model with _1dInterface support. |
Implementation of a two dimensional interface element with quadratic approximation of displacement field. Can be used to glue together two elements with quadratic displacement approximation along the shared edge. Note, that the nodes along the interface are doubled, each couple with identical coordinates. Nodes on the negative side are numbered first, followed by nodes on the positive part. Requires material model with _2dInterface support. The element features are summarized in Table 29.
| Keyword | Interface2dquad |
| Description | 2D interface element with quadratic approximation |
| Specific parameters | - |
| Unknowns | Two dofs (u-displacement, v-displacement) are required in each node. |
| Approximation | Quadratic approximation of displacements and geometry. |
| Integration | Full integration of all strain components using four point integration formula. |
| Features | - |
| CS properties | - |
| Loads | - |
| Nlgeo | 0 |
| Status | Reliable |
| Note | Element requires material model with _2dInterface support. |
Implementation of a three dimensional interface element with linear approximation of displacement field. Can be used to glue together two elements with linear displacement approximation along the shared triangular surface. Note, that the nodes along the interface are doubled, each couple with identical coordinates. Nodes on the negative surface are numbered first, followed by nodes on the positive part. The numbering of surface nodes on interface determines the positive normal (right hand rule). The surface in the direction of positive normal is the positive surface. Requires material model with _3dInterface support. The element features are summarized in Table 30.
| Keyword | Interface3dtrlin |
| Description | 3D interface element with linear approximation |
| Specific parameters | - |
| Unknowns | Three dofs (u-displacement, v-displacement, w-displacement) are required in each node. |
| Approximation | Linear approximation of displacements and geometry. |
| Integration | Full integration of all components using one point integration formula. |
| Features | - |
| CS properties | - |
| Loads | - |
| Nlgeo | 0 |
| Status | Reliable |
| Note | Element requires material model with _3dInterface support. |