# Rubber Damping Block

The following is true:

- For each force or torque direction using the Rubber-Damping formulation as specified in the [DIRECTION] block, the property file must contain a corresponding RUBBER_DAMPING block giving the thirteen (13) rubber damping parameters. The block name is a concatenation of RUBBER_BUSHING_ and the force or moment direction. For example, if the direction is TX, then the block name is [RUBBER_BUSHING_TX].
- The data block contains a scalar value that determines the number of preload sub-blocks: NPRELOADS = X
- For each preload there must be a corresponding data sub-block defined as: (PRELOAD_N) where N is a number from 1 to M with M being the total number of preloads.
- Each Rubber Bushing block in the property file must contain all thirteen (13) rubber damping parameters. The name, type and dimension for each parameter is listed in the table below.
- An optional 14th parameter, RMIN, is available to define the minimum cut-off time constant that the simulation model should use. If the value of the cut-off time constant, R, which is computed by the fitting tool, is less than RMIN, then RMIN is used. Large values of RMIN allow more frequencies to pass through the filtering mechanism. Also note that the frequency response of the bushing deviates from the experimental measurements that were made.
- When not specified, RMIN defaults to 0.0, a value that guarantees for RMIN not to be used.

The following table describes the parameters stored in a Constant Rubber Damping block. Abbreviations are: [A] = angle dimension, [F] = force, [L] = length, [T] = time.

Parameter | Type | Dimension FX, FY, FZ | Dimension TX, TY, TZ |
---|---|---|---|

R | real | [T^{-1}] |
[T^{-1}] |

K0 | real | [F][L^{-1}] |
[F][L]/Angle |

K1 | real | [F][L^{-1}] |
[F][L]/Angle |

K2 | real | [F][L^{-1}] |
[F][L]/Angle |

C0 | real | [F][T][L^{-1}] |
[F][T][L]/Angle |

C1 | real | [F][T][L^{-1}] |
[F][T][L]/Angle |

C2 | real | [F][T][L^{-1}] |
[F][T][L]/Angle |

P0 | real | No-Units | [F][L]/Angle |

P1 | real | [L^{-P2}] |
Angle[L^{-P2}] |

P2 | real | No-Units | No-Units |

Q0 | real | No-Units | No-Units |

Q1 | real | [L^{-Q2}][T^{Q2}] |
[Angle^{-Q2}][T^{Q2}] |

Q2 | real | No-Units | No-Units |

Optional | |||

RMIN | real | [T^{-1}] |
[T^{-1}] |

The following is an example of the RUBBER_DAMPING block for the X direction:

```
$---------------------------------------------------------------
[RUBBER_DAMPING_FX]
SPD_FILE_NAME = 'C:\Users\rajivr\Desktop\input_50289_fx.spd'
NPRELOADS = 1
(PRELOAD_1)
PRELOAD = 0.0000000000000000E+000
R = 3.7304938466506937E-001
C0 = 3.9148912713636901E+002
K0 = 1.4925221392833666E+003
C1 = 3.5544374604832620E+002
K1 = 1.2799236592247264E+004
C2 = 7.3796362578278907E-001
K2 = 1.0076285596442904E-001
P0 = 3.0189673042568872E+000
P1 = -2.3806569863314331E+000
P2 = 2.5826224628819706E-002
Q0 = 5.7885657452072947E-001
Q1 = -9.8019268585634856E-001
Q2 = 2.0000000000000000E+000
```