MADE Workflows > Conduct RBD Analysis

WF14: Conduct RBD Analysis

Pre-requisites

FBD Model: Indentured model required to Configure RBD and assign Reliability data to System model items.
RAM Module: RAM module shall be enabled to access RBD.
Mission Profile: Required in order to establish timeframe of RBD analysis.

Open an existing MADE Project.
Open the RBD Analysis of any parent model item (System/Subsystem) through the context menu (right click).
Highlight items to be included into a RBD group.
Select a RBD group from the icon menu or select (right-click) the RBD canvas.
Use the Properties viewer to enter RBD group details. Each RBD group type requires specific details.
Check that RBD groups have been fully defined for the indenture.
Check that the RBD analysis process has been defined for all other LOIs (Levels of Indenture).
Run a RBD analysis from the main menu (Menu: Reliability > ABD / RBD Analysis).

Select RBD Group Type: Series, Parallel, Exclusion, Complex, K/N Redundancy, Event Space
Enter RBD Group Details: Display Name, # of Functioning Items, Key Element, Key Element State

Additional RBD Group Required? — Yes → loop back to Select Model Items; No → All Indentures Defined? decision.
All Indentures Defined? — No → loop back to Select Model Items; Yes → Conduct RBD Analysis.

Reliability: Probability an item performs its intended function for specific intervals under stated conditions.
MTTF: Mean Time to Failure based on the Mission Duration.
MXTF: Equivalent to MTTF for item duration measured in non-time units (if defined).
Inherent Availability: Availability based solely on reactive maintenance.
Unavailability: Unavailability based solely on reactive maintenance.
Operating Availability: Based on maintenance downtime & logistic delay.
Duration of Operation: Amount of time (or other duration metric) an item is under active operation, drawn from Mission Profile or reliability settings.
Maintenance Times: Mean Time To Repair, Mean Maintenance Time.
MTTR: average time required to repair a failed item.
MMT: statistical mean of maintenance times, including corrective and preventive tasks.
MTBM: Mean Time Between Maintenance, including preventative and corrective actions.
MALDT: Mean Administrative and Logistical Downtime.
Replaceable: Yes/No depending on whether an item is designated as a LRU/SRU.
Failure Rate: Total number of failures within an item population divided by total life units expended by population during a measurement interval.
Characteristic Life: Time factor changing the shape of the probability distribution along the x-axis.
Slope: Slope of the regressed line in a Weibull probability plot.
Reports: Reliability-centric reports, including RBD Report.

Step 1: Open MADE Project

Project Explorer tree: Vehicle System [4/29] > Functions, Coupling, Driveline [11/11], Power Generation [3/14] > Functions, Control Unit, Diesel Engine [8/8] (highlighted) > Functions, Failure Diagram, Air Filter, Coupling 1, Engine, Governor, Injector Pump, Lift Pump, Primary Fuel Filter, Secondary Fuel Filter, Fuel Tank [3/3].
"Diesel Engine" system model canvas: Mission Profile "New Group", End Effect Item "Vehicle System"; shows Fuel Tank → Diesel Engine (Liquid/Gas/Electrical in-flows, Mechanical-rotational out-flow, red warning icon) and Control Unit → Diesel Engine (Continuous flow), feeding IN/OUT blocks.

Step 2: Open RBD Model

Context menu on "Diesel Engine" in Project Explorer: New > System Model, Failure Diagram, Functions; RBD Model (highlighted, tooltip "Open Reliability Block Diagram"), Maintenance Actions, Markov Analysis, Cut/Copy/Paste, Delete, End Effect Item, Response Paths, Override Failure Diagram, Failure Injection, Response Simulation, Load from Library, Save to Library, Advanced Properties.
"Diesel Engine" RBD canvas: R(t)=0.9992642 overall. Blocks: Lift Pump (0.9999089), Injector Pump (0.9999089), Engine (0.9999089), Coupling 1 (0.9999089) in series; Governor (0.9999016) below; Primary Fuel Filter, Air Filter, Secondary Fuel Filter (each 0.9999089) as dashed-connected parallel items on the right.

Step 3: Select Model Items

Same RBD canvas with Primary Fuel Filter, Air Filter, Secondary Fuel Filter items highlighted (orange) for grouping, R(t)=0.9992642 overall unchanged.

Step 4: Select RBD Group Type

Toolbar icons for RBD groups: S (Series), P (Parallel), C (Complex), Ev (Event Space), R (Standby Redundancy), K/N (K/N Redundancy, highlighted), E (Exclusion). Right-click context menu on canvas: Group > Series Group, Parallel Group, Complex Group - Decomposition Method, Complex Group - Event Space, Standby Redundancy Group, K/N Redundancy Group (highlighted, tooltip), Exclusion Group; also Ungroup, Zoom In/Out, RBD Reliability Analysis, RBD Equation Viewer, Monte Carlo, Hide RBD Groups, System Model Layout, Advanced Properties.

Step 5: Enter RBD Group Details

Grouped "K/N Redundancy Group 3.1" box containing Air Filter (0.999908...), Primary Fuel Filter (0.999908...), Secondary Fuel Filter (0.999908...) converging to a "1/3" node, overall R(t)=0.999999...
"Properties" panel for "K/N Redundancy Group": Name field, description "Redundant items all operate under constant, identical load." Fields: Functioning items (K) = 1, / Size (N) = 3 ("No. of functioning items required").

Step 6: Additional RBD Groups Required?

"Diesel Engine" RBD canvas showing nested groups: outer "Series Group 3.1" (R(t)=0.9996357) containing Engine, Lift Pump, Injector Pump, Coupling 1 (each R(t)=0.9999089) in series with inner "K/N Redundancy Group 3.2" (Air Filter, Primary Fuel Filter, Secondary Fuel Filter converging to "1/3", R(t)=0.9999999). Separate floating "Exclusion Group" box containing "Governor" (not yet grouped).

Step 8: Conduct RBD Analysis

'Analyses' menu: Fault Tree, Response Paths, Connection Matrix, Common Mode Analysis, Critical Item Analysis, Criticality & Reliability Editor, Technical Budget Analysis, Failure Rate Prediction, Markov Analysis, RBD Analysis (highlighted), Reliability Allocation Editor, Back-Fit RCM, Model-based RCM, Maintenance Cost Estimates.
"RBD" results table: columns Item, Item Number, LCN, Parent, Replaceable, t_op, and paired BASELINE/REVISED metric groups (R(t), MTTF (hrs), MXTF, A_I, Q, A_O, MTTR (hrs), MMT (hrs), MTBM (hrs), MALDT (hrs), λ/10^6 (hrs), β, η). Rows for Vehicle System (t_op 91.19444 hrs, R(t) 0.9988163, MTTF 68775.56), Series Group, Coupling, Driveline, sub-groups (Differential, Driveshaft, Transmission, Front/Rear wheel configuration with Parallel Group, 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, Air Filter, Primary Fuel Filter, Secondary Fuel Filter, Coupling 1, Engine, Injector Pump, Lift Pump, Fuel Tank, Inlet, Lining, Outlet, Vehicle — largely matching baseline and revised values.