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After you have added components to the system hierarchy, Lambda Predict automatically calculates results, such as failure rate and MTBF, for the individual items. The final calculated prediction results are based on the roll-up of all the individual block and component failure rates. The results can be displayed in the following areas:
You can also create plots of the results. See Prediction Plots.
Most results are displayed in the System Hierarchy panel in individual columns. (To hide or display columns, right-click anywhere in the system hierarchy, and then click Customize Columns to select which columns you want to display. These settings are stored per computer/username on the System Hierarchy page of the Application Setup, so any project that you open on this computer will have the same columns displayed.)
The following calculated results can be displayed:
Failure Rate(t=INF) is the steady-state failure rate (i.e., the constant failure rate at time = infinity)
MTBF is the mean time between failures, expressed in hours.
Contribution is the contribution made by the item to the failure rate of its direct parent. For example, a value of 0.5 in this column indicates that the item accounts for 50% of the failure rate of its direct parent. (See Highlight.)
For Bellcore/Telcordia predictions, the following results are also available:
Early Life Factor (also known as the first-year multiplier) is the ratio of the component's first-year failure rate to its steady-state failure rate.
Standard Deviation(t=INF) is the standard deviation at time = infinity (applies to Telcordia SR-332 Issues 2 and 3 only).
Failure Rate Upper Bound (t=INF) is the upper confidence bound for the steady-state failure rate (applies to Telcordia SR-332 Issues 2 and 3 only).
For MIL-217 predictions, the following results are also available:
Connection Failure Rate is the calculated failure rate due to the physical connections of components to a printed circuit board (PCB) or hybrid device. (See Custom Connection Types.)
The following results are available for MIL-217 predictions that specify non-operational phases:
Non-Operational Failure Rate is the steady-state failure rate during the non-operational phase.
Non-Operational MTBF is the mean time between failures, expressed in hours, during the non-operational phase.
Non-Operational Contribution is the contribution made by the item to the failure rate of its direct parent, during the non-operational phase.
For blocks that use redundancy, the following results are also available:
Mission Time is the mission duration, expressed in hours.
Failure Rate(t) is the expected failure rate at the specified mission time.
Unreliability(t) is the probability of failure at the specified mission time.
The Calculation Information window displays a report of the failure rate and pi factors for the item that is currently selected in the system hierarchy, and allows you to export the information to Excel. To view the report for a selected item, choose Prediction Tools > Data Views > Calculation Information.
This window can remain open while you click other items in the System Hierarchy panel; the results will be updated automatically to represent the current selection. If you make changes to an item’s properties while the window is open, click the Refresh View icon to update the values.
The pi factors that are displayed in this window are the same pi factors that can be displayed in the Pi Factor View.
You can generate template-based reports for your predictions. A basic report template is provided for each reliability prediction standard that is included with your license, as well as one for generic systems. You can also create your own custom report templates to meet specific needs. Reports are generated in Microsoft Excel, which provides maximum flexibility for additional post-generation edits and distribution.
To generate a report, select a standard item in the system hierarchy and choose Prediction Tools > Data Views > Report.
Select the check box of the template you wish to use for the report and click OK to generate the report. You can customize the appearance of the predefined report templates and also build and manage your own custom report templates. (See Creating and Editing Report Templates.)
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