Individual connector option tests

These verification cases test the performance of connector behavior options not routinely used in other verification problems. This section focuses on spring or damper behaviors via the connector elasticity and connector damping options. Both CARTESIAN and CARDAN connections are employed in these verification cases.

The behavior options are verified by applying a concentrated load with a connector element load and achieving a resulting relative displacement (for connector elasticity) or velocity (for connector damping) that corresponds to an analytical solution. Equivalent, non-connector elements are included for comparison.

For both the CARTESIAN and CARDAN connections the following connector elasticity cases are tested:

1. Connector elasticity with the connector's component of relative motion for which elastic behavior is specified set to 1 (CARTESIAN) or 4 (CARDAN) and the number of field variable dependencies set to 2 with the following dependency settings:

   1. Temperature = −10, field variable 1 = 1.0, field variable 2 = 0.5

   2. Temperature = 90, field variable 1 = 2.0, field variable 2 = 1.0

2. Connector elasticity with the connector's component of relative motion for which elastic behavior is specified set to 1 (CARTESIAN) or 4 (CARDAN), the number of field variable dependencies set to 1, and nonlinear behavior defined with the following dependency settings:

   1. Temperature = −10, field variable 1 = 1.0

   2. Temperature = 90, field variable 1 = 2.0

3. Connector elasticity with the connector's component of relative motion for which elastic behavior is specified set to 1 (CARTESIAN) or 4 (CARDAN), dependencies on components of constitutive motion included in the elasticity definition, and nonlinear behavior defined (no relevant temperature or field variable dependencies)

4. Connector elasticity with the connector's component of relative motion for which elastic behavior is specified set to 1 (CARTESIAN) or 4 (CARDAN), dependencies on components of relative position included in the elasticity definition, and nonlinear behavior and a periodic model defined (no relevant temperature or field variable dependencies)

5. Connector elasticity with the number of field variable dependencies included in the definition of connector elasticity data set to 2 (coupled)

   1. Field variable 1 = 1.0, field variable 2 = 0.5

   2. Field variable 1 = 2.0, field variable 2 =1.0

Similarly, for both the CARTESIAN and CARDAN connections the following connector damping cases are tested:

1. Connector damping with the connector's component of relative motion for which damping behavior is specified set to 1 (CARTESIAN) or 4 (CARDAN) and the number of field variable dependencies set to 2 with the following dependency settings:

   1. Temperature = −10, field variable 1 = 1.0, field variable 2 = 0.5

   2. Temperature = 90, field variable 1 = 2.0, field variable 2 = 1.0

2. Connector damping with the connector's component of relative motion for which damping behavior is specified set to 1 (CARTESIAN) or 4 (CARDAN), the number of field variable dependencies set to 1, and nonlinear behavior defined with the following dependency settings:

   1. Temperature = −10, field variable 1 = 1.0

   2. Temperature = 90, field variable 1 = 2.0

3. Connector damping with the connector's component of relative motion for which damping behavior is specified set to 1 (CARTESIAN), dependencies on components of relative position included in the damping definition, and nonlinear behavior and a periodic model defined (no relevant temperature or field variable dependencies)

4. Connector damping with the number of field variable dependencies included in the definition at connector damping data set to 1 (coupled) with the following dependency settings:

   1. Field variable 1 = 1.0

   2. Field variable 1 = 2.0

These verification cases test the connector rigid behavior. Both CARTESIAN and CARDAN connections are used.

The behavior options are verified by applying a concentrated load via a nodal concentrated load option, such that some force is created in the connector. Equivalent models with intrinsically constrained components of relative motion are created, and the results are compared.

These verification cases test the connector elastic-plastic and rigid-plastic behavior defined using the connector plasticity and hardening behaviors in association with procedures specifying connector elasticity and user-defined potentials in connector elements. An assembled connection using the basic connection types CARTESIAN and CARDAN is used. For the two-dimensional analyses, a CARTESIAN connection is used.

The behavior options are verified by applying a concentrated load with a connector element load and achieving a resulting relative motion or relative plastic motion that corresponds to an analytical solution.

These verification cases test the connector elastic (linear and nonlinear) and rigid-plastic behavior with damage defined using connector damage initiation and evolution in association with the procedures specifying connector elasticity, connector plasticity, and connector hardening behaviors. An assembled connection using the basic connection types CARTESIAN and CARDAN is used for all cases except one case where the assembled connection type BUSHING is used. For the two-dimensional analyses, a CARTESIAN connection is used.

These verification cases test the connector uniaxial behavior defined by prescribing the loading/unloading response for the component of relative motion using uniaxial behavior loading and unloading data. An AXIAL connection type is employed in these verification cases.

The behavior options are verified by applying a concentrated load and achieving a resulting relative motion that corresponds to the prescribed loading/unloading response.

This section focuses on stopping and locking behaviors defined with connector stop and connector lock definitions. Both CARTESIAN and CARDAN connections are used.

The behavior options are verified through a two-step load history. In Step 1 a concentrated load is applied with the connector load, such that the resulting connector motion will exceed the prescribed motion limits for either the connector stop or lock. In Step 2 the load direction is reversed to confirm the stopping or locking behavior. Equivalent, nonconnector elements are included for comparison. In the Abaqus/Standard tests a linear perturbation static step is performed in the third step.

For CARTESIAN connections the following connector lock cases are tested:

1. Connector lock with the component number on which the locking criterion is based set to 1 and all components of relative motion locked when the locking criterion is satisfied.

2. Connector lock with the component number on which the locking criterion is based set to 3 and the component number to lock, when the locking criterion is satisfied, set to 2.

For CARDAN connections, the following connector lock cases are tested:

1. Connector lock with the component number on which the locking criterion is based set to 4 and the component number to lock, when the locking criterion is satisfied, set to 4 (with rotation criterion) or 6 (with moment criterion)

2. Connector lock with the component number on which the locking criterion is based set to 4 and the component number to lock, when the locking criterion is satisfied, set to 4 (with rotation criterion) or 6 (with moment criterion)

For CARTESIAN and CARDAN connections, the following connector stop cases are tested:

1. Connector stop with the component number, for which the connector stop is defined, set to 1 (CARTESIAN) or 4 (CARDAN)

2. Connector stop with the component number, for which the connector stop is defined, set to 2 (CARTESIAN) or 6 (CARDAN)

This section focuses on connector failure behavior. Both CARTESIAN and CARDAN connections are employed in these verification cases.

The behavior option is verified by applying a concentrated load or displacement such that the connector failure limits are exceeded.

For CARTESIAN connections, the following connector failure cases are tested:

1. Connector failure with the connector's component number for which a failure criterion is defined set to 1 and all available components of relative motions released when the failure criterion is satisfied

2. Connector failure with the connector's component number for which a failure criterion is defined set to 3 and the available component of relative motion number to release, when the failure criterion is satisfied, set to 2

For CARDAN connections, the following connector failure cases are tested:

1. Connector failure with the connector's component number for which a failure criterion is defined set to 4 and all available components of relative motion released when the failure criterion is satisfied

2. Connector failure with the connector's component number for which a failure criterion is defined, set to 6, and the available component of relative motion number to release, when the failure criterion is satisfied, set to 4

This section focuses on Coulomb-like friction behaviors using the connector friction, connector derived components, and connector potentials. Most connection types for which friction can be defined are tested, including: AXIAL, CARTESIAN, RADIAL-THRUST, SLIDE-PLANE, SLOT, CARDAN, EULER, FLEXION-TORSION, ROTATION, REVOLUTE, UNIVERSAL, CYLINDRICAL, HINGE, PLANAR, TRANSLATOR, and UJOINT.

The behavior options are verified by applying concentrated loads or displacements to create nonzero contact forces and some relative motion in the connectors. The friction-related output quantities (friction forces, contact forces, and relative slip) are monitored to assess the solution quality. In the Abaqus/Standard tests both static and direct-integration implicit dynamic procedures are performed. In many of the Abaqus/Standard input files, perturbation procedures (steady-state dynamics, frequency, and random response) are also perfomed with or without the load case definition. Both the predefined and the user-customized friction behavior are tested. Various friction models as defined by the friction coefficient specified by the contact surface interaction or by changes to friction properties.

This section focuses on actuation behaviors using the available connector components of relative motion. CARTESIAN and CARDAN connections are used in these verification cases.

The available connector components of relative motion, with the values of variables being prescribed fixed at their values at the start of the step, are verified by inducing a relative displacement between the connector nodes in the first step of the load history, then fixing the motion and applying a concentrated load to verify no motion occurs.

The available connector components of relative motion, with a velocity or acceleration history specified, are verified by applying a relative velocity or acceleration to the connector element and obtaining a resulting relative displacement and connector load that correspond to the analytical solution for the prescribed conditions.

The available connector components of relative motion, with any nonzero magnitudes associated with prescribed variables defined in user subroutine DISP, are verified by applying a relative displacement between the connector nodes.

In the Abaqus/Standard tests a linear perturbation static procedure is performed in the last step.

Each of the cases listed above is tested.

These verification cases test connector elements with options not routinely tested in other verification problems: restart, element pair reactivation, and postprocessing analysis procedures.