The *TIE option joins two surfaces by eliminating the nodes on the slave surface with multi-point constraints. Multiple *TIE definitions may intersect. At these intersections the slave nodes are involved in an overconstraint. Only one *TIE constraint is needed to eliminate a slave node. Additional *TIE definitions are not needed.

In these tests intersecting *TIE definitions are used such that one or more slave nodes are included in more than one *TIE pair. Only one *TIE constraint should be enforced at any slave node.

A rigid body defined using the *RIGID BODY option eliminates all the degrees of freedom at the nodes of the rigid body in favor of the degrees of freedom at the reference node. Therefore, any *TIE option used to tie surfaces inside a single rigid body or between rigid bodies is a consistent overconstraint. In this case the *TIE option is ignored. Similarly, if the *TIE option is used to tie a rigid surface to a deformable surface and the surface on the rigid body is the slave surface, a consistent overconstraint exists for the *TIE nodes on the rigid body. If possible, ABAQUS reverses the master/slave pair.

In these tests the *TIE option is used to tie surfaces within a rigid body, between rigid bodies, or between a slave rigid body and a master deformable body.

If the *RIGID BODY option refers to nodes or elements that are already part of a rigid body, the common nodes will be involved in a consistent overconstraint.

In these tests the *RIGID BODY option is used to create a single rigid body from other individual rigid bodies, or to define a rigid body that includes a part of another rigid body.

The *TIE option eliminates the degrees of freedom at the slave nodes using multi-point constraints. If a *BOUNDARY definition is used to impose a boundary condition on the slave node, an overconstraint results.

In these tests the *TIE option is used to tie two surfaces, and the *BOUNDARY option is used to assign boundary conditions to the slave nodes such that a consistent overconstraint is created.

The *RIGID BODY option creates a rigid body that eliminates the degrees of freedom at all the nodes on the rigid body in favor of the degrees of freedom at the reference node. If the *BOUNDARY option is used to define a boundary condition at one of the eliminated nodes, an overconstraint results.

In these tests the *RIGID BODY option is used to define a rigid body, and the *BOUNDARY option is used to assign boundary conditions to eliminated nodes on the rigid body such that a consistent overconstraint is created.

If connector elements are used to connect nodes within a rigid body, a consistent overconstraint is introduced since the nodes at both ends of the connector element already have a rigid constraint. In this case the connector element should be removed. If multiple connector elements are used between rigid bodies, all kinematic constraints beyond three translational constraints and three rotational constraints (in three dimensions) or two translational constraints and one rotational constraint (in two dimensions) are overconstraints. In the case when the connector elements produce a consistent overconstraint between the two rigid bodies, all the connector elements are removed and a connector element of type BEAM is attached between the two rigid body reference nodes.

In these tests connector elements are connected either between nodes within a rigid body or between nodes on different rigid bodies.

The *RIGID BODY option eliminates all the degrees of freedom at the nodes belonging to the rigid body. If these nodes are also constrained by a *COUPLING option, an overconstraint may occur. ABAQUS/Standard will automatically eliminate the unncessary constraints associated the *COUPLING option.

The *TIE option eliminates the degrees of freedom at the slave node through multi-point constraints. If the tied surfaces intersect a surface where a contact interaction is defined (normal contact with or without Lagrange friction), the contact interactions at the slave node are overconstraints.

In these tests *TIE surfaces intersect surfaces with contact interactions.

Contact interactions and prescribed boundary conditions may lead to overconstraints if either normal contact with the default “hard contact” formulation or Lagrange frictional contact is used.

In these tests hard contact or Lagrange friction is defined, and the *BOUNDARY option is used to apply boundary conditions to contact slave nodes.