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 rectilinear spring, BranchiName. Nonlinear force-stretch relationships can be defined through the spring, which must be of type Fun1DType = RECTILINEAR_SPRING.
  2. Dashpot branches. A dashpot branch consists of a rectilinear dashpot, BranchiName. Nonlinear force-velocity relationships can be defined through the 1D function, which must be of type Fun1DType = RECTILINEAR_DASHPOT.
  3. Viscous branches. A viscous branch consists of an elastomeric viscous branch, BranchiName.
  4. Plastic branches. A plastic branch consists of an elastomeric plastic branch, BranchiName.

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 device elongation, ε, and 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 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.