3 MADE Modeling Overview

The purpose of a system is to perform a specified function, which is achieved by using material, signal, or energy flows. The objective of modeling is to construct a model which emulates a physical system. Once a model has been constructed, various scenarios can be simulated and analyzed, the results from which can be applied back to the real-world system.

MADE modeling workflows are summarized into the following overarching processes (Figure 2: MADE Modeling Processes):

• Process 1: System Modelling — Hardware, Logical Item
• Process 2: Functional Modelling — Functions, Flows, Flow Properties
• Process 3: System Behaviour Simulation — FCM & Bond Graph Simulation, Failure Injection, Response Simulation
• Process 4: Failure Analysis (Optional) — Failure Diagrams, FMEA, FMECA, FTA, Etc.

3.1 System Modeling (Process 1)

Each system, subsystem, component, part or pair is represented as a logical item (i.e. black box) in MADE. These logical items are placeholders for various information (e.g. functional, reliability, sensor information etc.) and need to be modeled before the functions and flows can be defined.

The system model structure is constructed based on the physical description, layout/schematic, or bill of materials of the real system. This is done by creating a block diagram in the system model editor, where each item exists as a black box.

Figure 3 shows an example system model ("Diesel Engine") with logical block items: Coupling 1, Air Filter, Secondary Fuel Filter, Engine, Lift Pump, Primary Fuel Filter, Injector Pump, Governor — bracketed by IN/OUT ports, under a Mission Profile "New Group" and End Effect Item "Power Generation".

3.2 Functional Modeling (Process 2)

Functional modeling enables the user to add additional details to logical model items regarding how their functions are performed, including the flows and flow properties involved. The system model is functionally defined by assigning functions to each item (black box). Once a function has been defined, input and output flows are required and are allocated along with specific flow properties selected by the user.

Next, inputs and output flows are connected using causal connections. The type of simulation required (FCM or Bond Graph) will influence the parameters that need to be set for the causal connection (see FCM Simulation & Theory and Bond Modeling Guides for more details).

After the item functions and flows have been included, the item flows are connected in the system model editor to complete the functional model. Figure 4 shows one system modeled for Bond simulation and another for FCM simulation. Note that feedback flows are not included in the FCM-compatible model.

Figure 4 (top — Diesel Engine, FCM simulation) shows flows such as Mass flow rate (Air Filter→Engine), Torque (Engine→OUT), Angular Velocity (Coupling 1), Flow rate (Lift Pump→Primary Fuel Filter→Secondary Fuel Filter→Injector Pump), Dynamic pressure (Injector Pump), Static pressure/Mass flow rate/Voltage/Amplitude (IN→Governor), Linear velocity (Governor).

Figure 4 (bottom — Driveline, Bond Graph simulation) shows the same driveline chain seen in the Bond Modeling Guide: SE(IN) → Transmission(1-IR) → Driveshaft(0-C) → Differential(1-IR) splitting into Front/Rear branches Half Shaft(0-C) → Planetary Gearbox(1-IRC) → Wheel Resistance(0-R) → Wheel(1-I) → SES(OUT), with Torque/Angular velocity flow labels throughout.

3.3 System Behavior Simulation (Process 3)

Once a functional model has been created it is crucial to test and verify the responses of flows in the model. Testing is performed using the Response Simulation feature, which involves injecting a hypothetical failure response into an output flow and simulating the propagated failures and effects throughout the system.

By injecting failures in the system model, failure responses can be measured and represented graphically using Response Simulation. These graphs can be reviewed by the modeler to ensure functional and behavioral correctness of the system. The more failures are injected and tested the more confident a user can be with the functional responses of a system, and resulting accuracy of failure analyses such as FMEA or FMECA.

Both FCM and Bond Graph simulations utilize Response Simulation:

• Figure 5: Response Simulation Graph for Bond-compatible items — shows a "Bond Response Simulation - Vehicle System" viewer with a tree of flow properties (e.g. Transmission Inductance, Inductor State, Resistance, "1 - I Angular velocity" (selected/plotted), "1 - R Angular velocity", "1 - R Torque", SE Coupling Angular velocity → Transmission Angular velocity, etc., and Wheel F items), plotted against a graph oscillating around 0 with a "FAILURE ACTIVATION" marker near x=50, settling near 0.0.
• Figure 6: Response Simulation Graph for FCM-compatible items — shows an "FCM Response Simulation - Vehicle System" viewer with a tree (Vehicle System > Coupling, Driveline, Power Generation > Control Unit, Diesel Engine > Air Filter, Coupling 1, Engine, Governor, Injector Pump, Lift Pump, Primary Fuel Filter (Liquid Flow rate selected/plotted), Secondary Fuel Filter, Mechanical-rotational Torque, Fuel Tank, Vehicle, Mechanical-rotational Angular velocity), plotted against a graph dropping from 0 and settling near -0.694.

3.4 Failure Analyses (Process 4)

Once a functional model has been completed, and its functional failure responses (e.g. high and low response) correctly defined, additional failure analysis can be performed using the Failure Diagram in MADE. The Failure Diagram provides the physical detail regarding the root causes of failure modes for each item in the system and allows for a more detailed FMEA or FMECA report.

Note: The definition of the failure diagram does not depend on the modeling approach and does not require a different approach for each method (FCM or Bond Graph).

Figure 7 shows an example Failure Diagram editor for a "Fuel Tank" item: root-cause failure mode leaf nodes (e.g. Untimely maintenance action (Lining), Damaged surface protection (Lining), Corrosive contaminant (Lining), Aerated liquid input (Lining), Pressure Differential (Lining), Insufficient surface protection (Lining), Insufficient bearing (Lining), Contaminated input flow (Lining), Solid particle contaminants (Lining)) feed via AND/OR logic gates into intermediate failure modes (Corrosion attack Inner Surface (Lining), Cavitation corrosion (Lining), then Perforated (Lining), Corroded (Lining), Pitted (Lining), Interference (Lining), Blocked (Lining), Leaked (Lining)) which converge into the top-level functional failure "Supply Liquid Static pressure (Lining) (Low)", ultimately rolling up to "Provide Liquid Static pressure (Fuel Tank)".