Elastomeric device definition

@ELASTOMERIC_DEVICE_DEFINITION {
@ELASTOMERIC_DEVICE_NAME {EldModlName} {
@ELASTOMERIC_DEVICE_TYPE {EldTyp}
@LIST_OF_BRANCH_NAMES {Branch1Name, Branch2Name, ..., BranchiName, ...}
@NUMBER_OF_SUB_TIME_STEPS {nsub}
@COMMENTS {CommentText}
}
}

Introduction

Figure 1. Configuration of the elastomeric device.

The elastomeric device, shown in fig. 1, is a force element consisting of any number of branches, all configured in parallel. The branches can be defined in any order. Elastomeric devices can be used in three different contexts.

  1. If EldTyp = FORCE_ELEMENT, the elastomeric device is connected to a flexible multibody system via the force element interface.
  2. If EldTyp = TORSIONAL, the elastomeric device is placed at the relative rotation of a kinematic constraint element.
  3. If EldTyp = RECTILINEAR, the elastomeric device is placed at the relative displacement of a kinematic constraint element.

Four types of branches are available to describe the behavior of the elastomeric device.

  1. Spring branches. A spring branch consists of a spring, BranchiName.
    • If EldTyp = FORCE_ELEMENT or EldTyp = RECTILINEAR, the spring defines a nonlinear force-stretch relationship and must be of type Fun1DType = RECTILINEAR_SPRING.
    • If EldTyp = TORSIONAL, the spring defines a nonlinear moment-rotation relationship and must be of type Fun1DType = TORSIONAL_SPRING.
  2. Dashpot branches. A dashpot branch consists of a dashpot, BranchiName.
    • If EldTyp = FORCE_ELEMENT or EldTyp = RECTILINEAR, the dashpot defines a nonlinear force-velocity relationship and must be of type Fun1DType = RECTILINEAR_DASHPOT.
    • If EldTyp = TORSIONAL, the dashpot defines a nonlinear moment-angular velocity relationship and must be of type Fun1DType = TORSIONAL_DASHPOT.
  3. Maxwell fluid branch. A Maxwell fluid branch, BranchiName, is a viscous branch of the model.
  4. Haupt-Sedlan branch. A Haupt-Sedlan branch, BranchiName, is a viscous branch of the model.
  5. Höfer-Lion branch. A Höfer-Lion branch, BranchiName, is a viscous branch of the model.
  6. Plastic branches. A plastic branch, BranchiName, is a viscous branch of the model.

The total force generated by the elastomeric device is the sum of the forces acting in each branch. The constitutive behavior of each of the branches depends on the elongation of the device, ε, and on its time derivative, dε/dt. The description and formulation of elastomeric devices provides the governing equations for the various branches.

NOTES

  1. All the branches that comprise the elastomeric device should be listed as, Branch1Name, Branch2Name, ... The order in which they appear is irrelevant.
  2. To guarantee the accuracy of the simulations, nsub sub-time steps are used to integrate the governing equations of the device. For more details, see the formulation of force element interfaces. (Default: nsub = 12.)
  3. It is possible to attach comments to the definition of the object; these comments have no effect on its definition.

Sensors

Sensors can be defined to extract information about elastomeric device. The following SensorType specifications are allowed for elastomeric devices: ELASTOMERIC_DEVICE_DATA or ELASTOMERIC_DEVICE_VISCOUS_DATA. (Default value: ELASTOMERIC_DEVICE_DATA).

It is also possible to request the evaluation of the hysteresis loop of the device.