Reliability Block Diagram

RBD - Reliability Block Diagram with Monte-Carlo simulation
RBD module allows performing the functional Reliability and Availability analysis of systems with variety of reliability distributions, all practically used types of redundant reliability configurations and repair factors. While the basic RAM Commander module provides reliability calculations and predictions for non-redundant systems, RBD utilizes data defined in other modules (reliability, maintainability, FMECA), and performs either analytical calculation or Monte Carlo simulation depending on the type of a system reliability configuration.

RBD-supported configurations

• Series RAMC RBD
• Parallel
• K-out-of-N with active (hot) redundancy
• K-out-of-N with stand-by (cold) redundancy
• Partially loaded K-out-of-N - warm redundancy
• K-out-of-N w/repair, w/o repair, w/restricted repair
• K-out-of-N with Switch
• Sub-RBD, K-out-of-N for Sub-RBD

The analytical technique is used mostly for exponential distributions. For each RBD, a graph of the reliability function R(t) can be drawn and MTBCF (Mean Time Between Critical Failures) can be calculated using numeric integration.
Monte Carlo simulation with its' high speed, required accuracy, and adjustable number of steps allows to evaluate Reliability and Availability for any user defined configurations for which no analytical solution can be found, i.e. the most complex configurations, including standby, partially loaded and active redundancy; full or restricted repair with non-exponential distribution of time-to-repair; analysis under non-steady, transient state; dependent RBD elements; analysis of periodical inspection policy.

RBD-supported Distributions

• Exponential  • Normal
• Log-Normal
• Weibull
• Erlang
• Uniform

RBD MTBCF Calculation
System Configuration feature of the RBD module is an ingenious answer to the requests of our customers who need to compare the reliability and availability of various system configurations created as the sub-sets of the project product tree. An ability to create an unlimited number of system configurations, easy transformation of each configuration into an RBD, MTBCF calculation, synchronized with the product tree changes, and finally a clear and elegant graphical presentation - all this makes the System Configuration feature an invaluable addition to the RAM Commander performance.
RAM Commander System Configuration





See also: