WF13: Assign Reliability Values

Pre-requisites

• RAM Module: RAM module is required for most reliability analysis capabilities in MADE.
• FBD Model: Required to select model items and enter reliability data.
• Mission Profile: Required in order to establish timeframe of FCM reliability analysis.
• Unit Life Configurations: Model items configured to accept Unit Life input (see WF41).
• Markov Analysis: Markov Analysis must be complete before assigned to an item to describe its reliability (see WF38).

Detailed Descriptions (numbered steps)

1. Open a MADE project.
2. Define the item's duration of operation, either directly through item properties or through Duty Cycles in MPD (see WF11).
3. If a target reliability is a requirement for the system or subsystem, child model item parameters may be automatically configured through Reliability Allocation Editor (see WF12).
4. Open Criticality & Reliability editor (Menu: Analyses > Criticality & Reliability editor).
5. Select a component or a part through the indentured system tree shown. Reliability analysis is a bottom-up analysis, therefore select items on the lowest level of indenture (parts if in hierarchy, otherwise components).
6. Assign the item's failure distribution type. If Markov distribution is required, a completed Markov Analysis must exist.
7. Configure failure distribution parameters.
8. Once reliability values are assigned an RBD Analysis can be run by clicking RBD Analysis under the Analysis option in the main menu bar.

Fields referenced in the diagram

• Define Duration of Operation: Direct Entry, Duty Cycles, Unit Life Accrual
• Assign Failure Distribution Type: Exponential, Weibull, Markov
• Configure Failure Distribution Parameters: Failure Rate/MTTF, Characteristic Life, Slope

Decision points

• Reliability Target Req.? — Yes → Go To WF12; No → Open Criticality & Reliability Editor.
• All Items Defined? — No → loop back to Select Model Item; Yes → Reliability Values Assigned.

Outputs

• MTTF: Displays the Mean Time to Failure based on the Mission Duration.
• Inherent Reliability: The reliability of the system without considering critical items.
• Inherent Availability: The probability a system will operate satisfactorily at any time under stated conditions in an ideal support environment without consideration for preventive action.
• Operating Context Reliability: The reliability of a system taking into account non-system failures.
• Charting: Charting capability allows quick generation of graphics based on reliability metrics such as poor performers and criticality.
• Reports: Reliability centric reports may be generated such as: RBD Report, Reliability Allocation Report, 1629A FMECA and CA.

Screenshot walkthrough (captions/labels extracted)

Step 1: Open MADE Project

• Module toolbar icons: MADE (system model), SRA (green chart), RAM (highlighted, blue), PHM. 'View' menu: Open Module (submenu highlighted) > MADE, SRA, RAM (highlighted), PHM; Open View, Reset Module, System Model Filtering, Capture screen, Show Grid, Snap to Geometry, Zoom In/Out.

Step 2: Define Duration of Operation

• "Mission Profile Definition - Regular Trip" > "Duty Cycles" tab: Duty Cycle Details table (same as WF11 step 11) with instructions about entering Duty Cycle percentages per Phase/Segment column, and per-item rows (Vehicle System, Coupling, Driveline and sub-items, Power Generation, Control Unit, Diesel Engine and sub-items).
• "Properties" panel for "Coupling 1" (highlighted box): Duration of Operation (hrs) = "91.09722", Failure Distribution Type dropdown = "Exponential". "Mean Time To Failure (MTTF)": 1000000.00 hours (114.077 years) — note "The MTTF must be between 1.0 and 1.0E15 hours." "Part Failure Rate (/10^6 hours)": 1E0, slider range 1E-9 to 1E5.

Step 4: Open Criticality & Reliability Editor

• 'Analyses' menu: Fault Tree, Response Paths, Connection Matrix, Common Mode Analysis, Critical Item Analysis, Criticality & Reliability Editor (highlighted), Technical Budget Analysis, Failure Rate Prediction, Markov Analysis, RBD Analysis, Reliability Allocation Editor, Back-Fit RCM, Model-based RCM, Maintenance Cost Estimates.
• "R/C Properties Editor" — "Criticality & Reliability Editor": "Item/Failure Selection" tree (Vehicle System > Convert > Mechanical - rotational Angular velocity x2, Coupling, Driveline, Power Generation, Vehicle) with mode dropdown showing Criticality / Reliability (Reliability highlighted). Right panel "Reliability Help": "Select one of the following to edit its Reliability:" with icons/labels Component, Part, Function Flow, Failure - Fault.

Step 5: Select Model Item

• "Criticality & Reliability Editor" tree expanded: Vehicle System > Convert (Mechanical - rotational Angular velocity x2), Coupling > Couple, Driveline, Power Generation > Convert, Control Unit (selected), Diesel Engine, Fuel Tank; Vehicle.
• Right panel "General Reliability" for "Control Unit": Duration of Operation (hrs) 91.09722, Mean Time To Repair (hrs) 1.00, Failure Distribution Type "Exponential". "Exponential" section: Mean Time To Failure (MTTF) 2593.87 hours (3.551 months), Part Failure Rate (/10^6 hours) 3.8552E2 (slider 1E-9 to 1E6). "Operational Availability": Delay Time (hrs) 0.00, Turn Around Time (hrs) 0.00, Spares on Hand 0. "Monte Carlo - Exponential": Part Failure Rate - Standard Deviation 1.00 (slider 0-100). Graph plotting p(f) vs Time (hrs), linear rising line 0 to ~0.04 over 0-95 hrs.

Step 6: Assign Failure Distribution Type

• Failure Distribution Type dropdown expanded showing options: Exponential (selected), Exponential (Unit Life), Weibull, Weibull (Unit Life). Shown both in the Criticality & Reliability Editor view (for "Control Unit") and in the item's "Properties" panel (Reliability tab).

Step 7-1: Configure Failure Distribution Parameters (Exponential)

• "General Reliability": Duration of Operation (hrs) 91.09722, Mean Time To Repair (hrs) 3.00, Failure Distribution Type "Exponential". "Operational Availability": Delay Time (hrs) 3.00, Turn Around Time (hrs) 5.00, Spares on Hand 2. "Exponential": Mean Time To Failure (MTTF) 8000.00 hours (10.951 months), Part Failure Rate (/10^6 hours) 1.25E2 (slider). Graph: p(f) rising linearly from 0 to ~0.0125 over 0-90 hrs. Shown both in Criticality & Reliability Editor and item Properties panel for "Control Unit".

Step 7-2: Configure Failure Distribution Parameters (Weibull)

• "General Reliability": Mean Time To Repair (hrs) 5.00, Failure Distribution Type "Weibull". "Operational Availability": Delay Time 5.00, Turn Around Time 12.00, Spares on Hand 0. "Weibull": Slope 3.00 (range 0.01-6), Characteristic Life 1E4 (range 1E0-1E15). Graph: p(f) curve rising exponentially from near 0 to ~0.0000008 over 0-95 hrs. Shown for item "Air Filter" in its Properties panel (Reliability tab): Slope 3.00, Characteristic Life 1E4.

Step 7-3: Configure Failure Distribution Parameters (Markov)

• "General Reliability": Duration of Operation (hrs) 91.09722, Mean Time To Repair (hrs) blank, Failure Distribution Type "Markov", Active Markov Analysis dropdown "Primary Fuel Filter Markov". "Operational Availability": Delay Time 3.00, Turn Around Time 5.00, Spares on Hand 2. Shown for item "Primary Fuel Filter" in its Properties panel (Reliability tab) with the same Active Markov Analysis selection.

Step 8: All Items Defined?

• "RBD" viewer table with columns Item, Model t_op, and paired BASELINE / REVISED metric sets: R(t), MTTF (hrs), MXTF, A_I, Q, A_O, MTTR (hrs), MMT (hrs), MTBM (hrs), MALDT (hrs). Rows for Vehicle System (t_op 1.30278 hrs, R(t) 0.999983, MTTF 68775.56) down through Series Group, Coupling, Driveline, Series Group, Differential, Driveshaft, Transmission, Wheel configuration (Parallel Group), Front/Rear wheel configuration (Half Shaft Front/Rear, Planetary Gearbox Front/Rear, Wheel Front/Rear, Wheel Resistance Front/Rear), Power Generation, Control Unit, Diesel Engine, K/N Redundancy Group, Coupling 1, Engine, Injector Pump, Lift Pump, Fuel Tank, Inlet, Lining, Outlet, Vehicle — each with matching Baseline/Revised values (mostly identical, e.g. R(t) ~0.999999, MTTF ~1000000.00 for leaf items with default reliability, down to 68775.56/194805.19/etc. for aggregated groups).

Related workflows

• WF11 – Create Mission Profiles (duration of operation via Duty Cycles)
• WF12 – Conduct Reliability Allocations
• WF38 – Conduct Markov Analysis
• WF41 – Entering Cycle Based Reliability Values (Unit Life)