4 Relevant Editors and Windows

There are three major viewers that are best used when reviewing failure simulation in MADE. The Propagation Table and Response Simulation viewers are used for both FCM and Bond Graph failure simulation. The Step Table viewer is a specific FCM viewer that presents each step in the FCM calculation.

Propagation Table

The propagation table is a viewer that presents failure modes that occur in the system and the responses to these failures that would be observed at points across the system.

Response Simulation

The response simulation viewer is a graphical view of the simulation. It shows the progression of individual flow properties over the duration of the simulation.

Step Table

The step table is a tabulated view of an FCM simulation. FCM is a step-based analysis meaning the value of each flow property is calculated (one step), these values are the input values to the next step of analysis where the flow property values are again calculated (the next step). Each flow property in the model is presented in the step table as rows, and the value of each flow property at each step is presented across the table in the columns.

Depending on whether a failure has been injected into the system, the step table will either show the FCM steps from initial values to the nominal state (equilibrium) of the system, or it will show the FCM steps from the nominal state to the final steady state of the simulation in response to the injected failure.

5 User Workflow for Reviewing Failures

Failure simulation for the purposes of analyses such as PHM or FMEA is essentially automatic. Once a model has been built MADE will process any required failure simulation as a part of preparing any analysis it is required for. However, when building a model, it is prudent to manually check the failure simulation as you go in order to confirm the model is closely simulating the real system.

The workflow outlines a manual way to review failures and how to better understand how MADE fundamentally goes about its failure simulation.

Figure 2 ("User Workflow to Check and Review Failures") depicts a 7-step linear workflow with accompanying descriptions:

1. Run Response Simulation — Check graph and see it progressing from the initial values to an equilibrium.
2. Step Through Simulation Whilst Viewing Step Table — Step through the simulation and view the step table to see how the simulation progresses from each step and how these steps match up with the previously examined response simulation graph.
3. View Final Values — The final values both in the response graph (and step table) are taken as the nominal values of the system and it is against these values that failures will be compared against.
4. Inject a Failure and Step Through Simulation — Inject a failure into the model by perturbing an item's flow property (directly in the case of FCM or via a bond variable for bond graph simulation). Step through the failure simulation noting that the values begin at the previously established nominal state.
5. Check Response Simulation — Checking response simulation it can be observed that the simulation has two segments. The first area of the graph shows the simulation free of failure to the point of equilibrium, the second area of the graph shows the simulation once a failure has been introduced to a second equilibrium (or steady state).
6. Response Direction — The response of a flow property to failure is taken by comparing the final steady state after failure to the nominal value. If the steady state is greater than the nominal value the response is considered high, if less than it is considered low, and if within a defined range is considered nominal (or no change).
7. View the Propagation Table — The propagation table contains responses to all failures in the system. A row in the prop table represents one failure being simulated and will match up with the final column seen in the step table after the failure has been simulated.