Dashpot definition

@DASHPOT_DEFINITION {
@DASHPOT_NAME {DashpotName} {
@FUNCTION_1D_TYPE {Fun1DType}
@FUNCTION_1D_NAME {Fun1DName}
@FUNCTION_1D_NAME {Fun1DNameDeriv}
}
}

Introduction

A dashpot defines the nonlinear relationship between the viscous force and stretch rate of a viscous dashpot. Two types of dashpots can be defined.

1. Rectilinear dashpots define the relationship between the dashpot viscous force, Fvi, and stretch rate, v. Rectilinear dashpots are used with relative displacement elements or are part of a more complex elastomeric device model.
2. Torsional dashpots define the relationship between the dashpot viscous moment, Mvi, and twist rate, ω. Torsional dashpots are used with relative rotation elements or are part of a more complex elastomeric device model.

NOTES

1. Parameter Fun1DType defines the nature of the dashpot. It can take either of two values.
1. Fun1DType = RECTILINEAR_DASHPOT defines a rectilinear dashpot, and
2. Fun1DType = TORSIONAL_DASHPOT defines a torsional dashpot.
2. The characteristics of the dashpot are defined by 1D function, Fun1DName, F = F(x), which maps to Fvi = Fvi(v) and Mvi = Mvi(ω) for the rectilinear and torsional dashpots, respectively. The 1D function can be a Chebyshev function, a harmonic function, a tabulated function, or a user function. For tabulated functions, the discrete function must approximated by its expansion in terms of Chebyshev polynomials.
3. It will also be required to compute the derivative of the dashpot force or moment with respect to the velocity or angular velocity, respectively. If the 1D function is defined as a Chebyshev, harmonic, or tabulated function, this derivative is computed analytically and a 1D function associated with this derivative will be generated automatically. If the 1D function is defined as a user function, this derivative must be provided as an independent user function, Fun1DNameDeriv. In this case, both Fun1DName and Fun1DNameDeriv must refer to user functions.
4. It is possible to attach comments to the definition of the object; these comments have no effect on its definition.