# Rotational Damper

Linear rotational damper

Libraries:
Simscape / Driveline / Couplings & Drives / Springs & Dampers

## Description

The Rotational Damper block represents a linear rotational viscous damper. The block calculates the torque transmitted by the damper such that

`$T=D\omega$`

and

`$\omega ={\omega }_{R}-{\omega }_{C},$`

where

• T is the torque transmitted through the damper.

• D is the damping (viscous friction) coefficient.

• ω is the relative velocity.

• ωR and ωC are the absolute velocities of ports R and C, respectively.

The positive block direction is from port R to port C. Therefore, the torque is positive if it acts in the direction from R to C.

### Faults

To model a fault in the Rotational Damper block, in the Faults section, click the Add fault hyperlink next to the fault that you want to model. When the Add Fault window opens, you can to specify the fault properties. For more information about fault modeling, see Fault Behavior Modeling and Fault Triggering.

When you trigger a fault, the block applies the value of the Faulted damping coefficient parameter for the remainder of the simulation.

### Thermal Modelling

You can model the effects of heat flow and temperature change by enabling the optional thermal port. To enable the port, set Thermal port to `Model`.

Enabling thermal modelling exposes the Thermal mass parameter.

### Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.

## Ports

### Conserving

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Mechanical rotational conserving port associated with the rod interface.

Mechanical rotational conserving port associated with the case interface.

Thermal conserving port associated with heat flow. Heat flow affects damper temperature, and therefore, power transmission efficiency.

#### Dependencies

To enable this port, set Thermal port to `Model`.

## Parameters

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### Main

The oscillation-reducing torque due to viscous friction that the block applies if no trigger event occurs. Specify a value that is greater than or equal to zero.

### Faults

To modify the faults, create a fault and, in the block dialog, click Open fault properties. In the Property Inspector, click the Fault behavior link to open the faults.

Whether to model a fault in the block. To add a fault, click the Add fault hyperlink.

Damping coefficient once a fault trigger occurs.

#### Dependencies

To enable this parameter, enable faults for the block by clicking the hyperlink.

### Thermal port

Option to model effects of heat flow and temperature change.

Thermal energy required to change the component temperature by a unit increase. The thermal mass represents the ability of the damper to absorb and retain heat energy.

## Version History

Introduced in R2016b

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