RAM Commander User Manual

To enter data for an RBD element

To enter data for an RBD element

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To enter data for an RBD element

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Do one of the following:

From the Item menu, choose Edit. In the Element Parameters Definition dialog box, enter the element’s specifications. Choose OK.

 or

Activate the Product tree view. Drag and drop a tree item into the RBD element; RAM Commander displays the reliability data.

RAM Commander updates the reliability block diagram.

The Element parameters definition dialog box contains several fields, as shown below:

RBD_ElementData

When you add elements to the RBD, you must specify their characteristics in the Element parameters definition dialog box’s fields. These characteristics include:

FR distribution

A probability density function describing the part’s failure rate.

FR distribution parameters

Parameters describing the FR distribution, such as μ and σ for the Normal distribution or MTBF for exponential distribution.

K-out-of-n

K—the minimum number of units that must operate for the element to function

N—the total number of units in the element

Load defines the status of non-functional elements:

  Load = 0 - Element non-operating - standby redundancy

  0 < Load < 100 - Element partially stressed warm redundancy

  Load = 100  - Element with active redundancy

Repair

Specifies the repair policy for failed elements. If you select Restricted or Full repair, you must specify the distribution for the repair time as for the FR distribution.

  Without repair - Element is not repaired upon failure. (The repair distribution parameters are ignored.)

  Restricted repair - Only one element is repaired at a time (queuing for repair).

  Full repair - Any number of elements can be simultaneously repaired (no queuing).

Inspection period

Applicable for Monte Carlo simulations only and if the element has either Restricted or Full repair.

Inspection Period check box not checked - Element sent to repair upon RBD failure.

Inspection Period check box checked and value = 0 - Element sent to repair upon component failure (default).

Inspection Period check box checked and value > 0 - Element checked every [Inspection Period] hours. If failed, sent to repair.

Duty cycle

Amount of time the part is operational relative to mission time.

ID

Taken from the product tree; used for updating element data from the product tree.

FM Number

Taken from the FMECA analysis; used for updating element data from FMECA.

Description

For descriptive purposes only.

Part number

Taken from tree data; for descriptive purposes only.

Ref. Des.

Reference designator - element name. Taken from product tree data. If multiple elements have the same Reference designator, "Identical" calculation and simulation recognizes them as identical and then assumes that it is a single equipment block even if it appears in multiple places in the RBD.

Remark

For descriptive purposes only.