WF08: Conduct Failure Simulation

Pre-requisites

• FBD Model: to inject failure(s) and propagate throughout, producing failure simulations.
• Failure Diagram: FFMs at the minimum, supplemented by failure conditions, if required. Simulation and criticality parameters should be defined for failure concepts and connections.

Detailed Descriptions (numbered steps)

1. Select model item and access 'Failure Injection' via the right-click context menu.
2. Inject failure by selecting 'Up', 'Down' or Perturb by Value on any given component.
3. Use the shortcut icons in the toolbar to control the failure simulation.
4. Inject another failure at the necessary time step, if more complex failure simulations are required.
5. Run the failure simulation until equilibrium with the shortcut icons in the toolbar.
6. Access and review the resultant Step Table, which is a tabulated representation of the failure simulation.
7. Access and review the Response Simulation Graphs due to your injected failure(s), which are visual representations of the failure simulation.
8. Failure Simulations conducted, validates the model for further analyses.

Fields referenced in the diagram

• Inject Failure options: 'Up' Failure, 'Down' Failure, Perturb by Value

Decision points

• Inject Another Failure? — Yes → loop back to Inject Failure; No → Run Failure Simulation.

Outputs

• Step Table: tabulated representation of the failure simulation, exported as a .csv file.
• Response Graph: visual representation of the failure simulation, exported as a .png file.

Screenshot walkthrough (captions/labels extracted)

Step 1: Access Failure Injection

• "Vehicle System" canvas (Mission Profile: Regular Trip) showing Power Generation, Coupling, Driveline, Vehicle blocks feeding IN/OUT. Right-click context menu on "Coupling": System Model, Failure Diagram, Bond Graph, Functions, Maintenance Actions, Cut/Copy/Paste, Delete, Zoom In/Out, End Effect Item, Fault Tree, Response Paths, Propagate All..., Override Failure Diagram, Failure Injection (highlighted) > submenu listing failure flow properties "Mechanical - rotational Torque" and "Amplitude" (each expandable), Response Simulation, Save to Library, Advanced Properties.

Step 2: Inject Failure

• Four "Failure Injection" submenus shown, each for "Mechanical - rotational Torque" / "Amplitude", offering Up / Down / Perturb by Value options, with Up, then Down, then Perturb by Value highlighted in turn.
• "Perturb by Value - Couple Mechanical - rotational Torque (Coupling)" dialog: "Use the slider below to define the direction and strength of perturbation." Perturbation field/slider (0.00, range -4 to 4). Buttons: OK, Cancel.

Step 3: Control Failure Simulation

• "Vehicle System" canvas with a toolbar of playback controls (Play, Step Forward, Mute/Step Back, Undo, Save, Screenshot icons) above the canvas. Banner: "Functional Perturbation: [Up icon] Couple Mechanical - rotational Torque (Coupling)". First screenshot shows the initial state (Power Generation, Coupling, Driveline, Vehicle blocks, red warning icon on Power Generation). Second screenshot shows the same canvas after simulation steps, with propagated failure indicators "↓3" / "↑3" annotations at Power Generation, Coupling, Driveline, and Vehicle (SES nodes) reflecting the perturbation spreading through the model.

Step 6: Review Step Table

• "Step Table - Vehicle System" viewer: columns Component, Flow Property, and numbered time steps (i, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, =). Rows list each component/flow property pair (e.g. Air Filter/Gas Mass flow rate = 0.0, Coupling/Mechanical - rotational Torque showing up-arrow 1.0 values from step 1 through 11, Differential/Mechanical - rotational Angular velocity starting at step 5, Driveline/Mechanical - rotational Angular velocity, Driveshaft/Mechanical - rotational Torque from step 3, Engine/Mechanical - rotational Torque, Fuel Tank/Liquid Static pressure = 0.0, Governor/Mechanical - linear Linear velocity = 0.0, Half Shaft Front/Rear, Injector Pump/Liquid Dynamic pressure = 0.0, Lift Pump/Liquid Flow rate = 0.0, Planetary Gearbox Front/Rear, Power Generation/Mechanical - rotational Torque, Primary/Secondary Fuel Filter/Liquid Flow rate = 0.0, Transmission/Mechanical - rotational Angular velocity from step 2, Vehicle/Vehicle System rows, Wheel Front/Rear, Wheel Resistance Front/Rear). Toolbar icons: Play, Step Forward, Step Back, Undo, Save, table/grid view, export, screenshot.

Step 7: Review Response Simulation

• "FCM Response Simulation - Vehicle System" viewer: checklist tree (Vehicle System > Coupling > Mechanical - rotational Torque (checked), Driveline > Differential, Driveshaft, Half Shaft Front/Rear, Planetary Gearbox Front/Rear, Transmission, Wheel Front (checked)/Rear, Wheel Resistance Front/Rear, Mechanical - rotational Angular velocity, Power Generation). Graph: y-axis -1.2 to 1.2, x-axis 1-13, shaded "FAILURE ACTIVATION" region from ~1 to ~9; red line ramps from 0 to 1.0 and holds; blue line stays at 0 then ramps up starting around x=9, both ending near 1.0.
• "Bond Response Simulation - Vehicle System" viewer: checklist tree (Vehicle System > Coupling > Amplitude (checked), SE Coupling Angular velocity -> Transmiss[ion], SE Coupling Torque -> Transmission Torqu[e]; Driveline > Differential > Inductance, Inductor State (checked), Resistance, 1 - I Angular velocity, 1 - I Torque, 1 - R Angular velocity, 1 - R Torque, Differential Angular velocity -> Half Sh[aft], Differential Torque -> Half Shaft Front). Graph: y-axis 0 to 1, x-axis 0-100, shaded "FAILURE ACTIVATION" region from 0 to 50; red line at 0.9 dropping to 0.36 at x=50 and holding; blue oscillating line settling around 0.4, with end labels 0.36 and 0.4.