5.5.2.1. FRA Excitation Loads

User can set a FRA Input Channel and FRA Output Channel.

• FRA Input is provided as follows.

  • Force/Torque: FX, FY, FZ, TX, TY, and TZ.

  • Displacement: DX, DY, DZ, RX(Roll), RY(Pitch), and RZ(Yaw).

  • Velocity: VX, VY, VZ, WX, WY, and WZ.

  • Acceleration: ACCX, ACCY, ACCZ, WDTX, WDTY, and WDTZ.

• FRA Output is provided as follows.

  • Displacement: TX, TY, TZ, RX(Roll), RY(Pitch), RZ(Yaw), and TM.

  • Velocity: VX, VY, VZ, WX, WY, WZ, VM, and WM.

  • Acceleration: ACCX, ACCY, ACCZ, WDTX, WDTY, WDTZ, ACCM, and WDTM.

Figure 5.30 FRA for MBD/RFlex dialog box

• Input Channel

  There are two types as Marker and Expression.

  • Marker type

    

    Figure 5.31 Marker type of the FRA Input

    • Marker: User can select a marker.

    • Type: FX, FY, FZ, TX, TY, TZ, DX, DY, DZ, RX(Roll), RY(Pitch), RZ(Yaw), VX, VY, VZ, WX, WY, WZ, ACCX, ACCY, ACCZ, WDTX, WDTY, and WDTZ.

    • Reference Frame: There are two options as Local and Global. Local reference frame means that the X, Y, and Z axis of input force or torque is defined as the selected marker. Global reference frame means that the X, Y, and Z axis of input force or torque is defined as Ground.InertiaMarker.

    • Actuator: User can select an actuator in the actuator library.

  • Expression type

    

    Figure 5.32 Expression type of the FRA Input

    • Marker, Type, Ref. Frame, and Actuator: Refer to Marker type of FRA input.

    • Expression: User can set of magnitude value of the FRA input force/torque with an expression. This value can be set in Expression type of FRA input.

• Output Channel

  • Marker type

    

    Figure 5.33 Marker type of the FRA Input

    • Marker: User can select a marker.

    • Type: TX, TY, TZ, RX, RY, RZ, VX, VY, VZ, WX, WY, WZ, ACCX, ACCY, ACCZ, WDTX, WDTY, WDTZ, TM, VM, WM, ACCM, and WDTM.

    • Ref. Frame: There are two options as Local and Global. Local reference frame means that the X, Y, and Z axis of input force or torque is defined as the selected marker. Global reference frame means that the X, Y, and Z axis of input force or torque is defined as the inertia reference frame.

  • Expression

    

    Figure 5.34 Expression type of the FRA Output

    • User can freely make an FRA output channel with the expressions. For more information about Expression, click here.

• Actuator Library

  An actuator is created by default named Actuator1.

  

  Figure 5.35 Actuator Library

  • Actuator: User can set and modify the name.

  • Type: There are 4 type named Swept Sine, Rotating Mass, PSD, User.

  • Info: User can set and modify the parameters of the selected actuator. These parameters influence to the Frequency Response with Actuator of the FRA Plot data.

    • Swept Sine is consistent for two parameters as magnitude and phase angle. In order to set the parameters, click Info.

      • Force Magnitude: Is a dimensionless magnitude factor for the actuator input. This factor is multiplied to the Input channel.

      • Phase Angle: Is a shift angle for the actuator input. This angle shifts the phase of Input channel. The unit is a degree.

      • For example, if the input is \(\sin (\omega t)\), Force Magnitude is \(\alpha\), and Phase angle is \(\phi\), then the result response (\(y\)) is evaluated as \(y=Hu_{actuator}\). Here, \(u_{actuator}=\alpha \sin (\omega t+\phi )\).

      

      Figure 5.36 Actuator Library: Swept Sine

    • Rotating Mass is consistent for two parameters as magnitude and phase angle. In order to set the parameters, click Info.

    • Force Type: Is a dimensionless magnitude factor for the actuator input which is represented by two actuators. This factor is multiplied to the Input channel. The Leading and Lagging actuators are represented:

      

    • Moment Type: Is a shift angle for the actuator input. This angle shifts the phase of Input channel. The unit is a degree.

      

      Each leaing type and lagging type actuators could be applied on the same input channel. The first actuator should be defined as a Leading actuator and the second as the Lagging actuator.

      

      Figure 5.37 Actuator Library: Rotating Mass

    • PSD(Power Spectral Density) is consistent for two parameters as magnitude and phase angle. In order to set the parameters, click Info.

    • Force Magnitude: Is a dimensionless magnitude factor for the actuator input which is defined by using a spline function. This factor is multiplied to the Input channel.

    • Phase Angle: Is a shift angle for the actuator input. This angle shifts the phase of Input channel. The unit is a degree.

    • For example, if the input is \(\sin (\omega t)\), Force Magnitude is \(\alpha\), and Phase angle is \(\phi\), then the result response (\(y\)) is evaluated as \(y=Hu_{actuator}\). Here, \(u_{actuator}=\alpha \sin (\omega t+\phi )\).

      ( PSD type actuator cannot use with the vibration actuators of the other type.)

      

      Figure 5.38 Actuator Library: PSD

    • User is consistent for two parameters as magnitude and phase angle. In order to set the parameters, click Info.

    • Force Magnitude: Is a dimensionless magnitude factor for the actuator input which have a function using the variable “freq”. This factor is multiplied to the Input channel.

    • Phase Angle: Is a shift angle for the actuator input. This angle shifts the phase of Input channel. The unit is a degree.

    • For example, if the input is \(\sin (\omega t)\), Force Magnitude is \(\alpha\), and Phase angle is \(\phi\), then the result response (\(y\)) is evaluated as \(y=Hu_{actuator}\). Here, \(u_{actuator}=\alpha \sin (\omega t+\phi )\).

      

      Figure 5.39 Actuator Library: User