Table of Contents

Drivetrain Shaft Brakes

The mechanical shaft brake is used for simulations of stopping or parked rotors. Up to three shaft brake characteristics may be defined. This might capture different torque settings, or if different numbers of callipers are used. The brakes can be applied through the external controller, although this feature is not yet supported in NG demo 2.

Specify the BrakePosition to define whether the brake is located on the high-speed or low-speed shaft. When the brake is applied, it usually takes a little time to reach full torque. Two ways are provided for specifying how the brake torque develops, SimpleShaftBrake or NonLinearShaftBrake.

Simple Shaft Brake

The SimpleShaftBrake brake type applies the brake torque linearly from zero up to full braking torque, as illustrated in Figure 1

Figure 1

Figure 1: Illustration of how the brake torque is calculated using SimpleShaftBrake.

SimpleShaftBrake has two properties:

  • MaximumTorque: The maximum retarding torque to apply to the shaft.
  • RampTime: The amount of time following the brake's activation to reach maximum torque.

Example of a SimpleShaftBrake using 2 brakes:

    "ShaftBrakes": [
    {
        "MaximumTorque": 100000.0,
        "RampTime": 1.0,
        "BrakeType": "SimpleShaftBrake",
        "BrakePosition": "HIGH_SPEED_SHAFT_GEARBOX_END"
    },
    {
        "MaximumTorque": 50000.0,
        "RampTime": 2.0,
        "BrakeType": "SimpleShaftBrake",
        "BrakePosition": "LOW_SPEED_SHAFT_GEARBOX_END"
    }
    ],

Non Linear Shaft Brake (lookup table)

The braking torque may be specified as a time history of braking torque against time since the brake application was initiated. This is done by the use of the TimeVsTorque lookup table, which is the relationship between the time following the brake's activation, and the retarding torque it applies to the shaft. This is illustrated in Figure 2

Figure 2

Figure 2: Illustration of how the brake torque is calculated using NonLinearShaftBrake.

Example of a NonLinearShaftBrake:

    "ShaftBrakes": [
    {
        "TimeVsTorque": [
        {
            "Time": 0.0,
            "Torque": 0.0
        },
        {
            "Time": 1.0,
            "Torque": 10000000.0
        }
        ],
        "BrakeType": "NonLinearShaftBrake",
        "BrakePosition": "LOW_SPEED_SHAFT_GEARBOX_END"
    }
    ],