Analytical Plots
Plots can be created and viewed by clicking the Plot
icon located on the Analytical page of the control panel for each
diagram.
If you click the Plot
icon before the diagram has been analyzed, it will automatically
be analyzed and then the data will be plotted in the plot sheet.
(Note that the Plot icon
on the Plot sheet control panel refreshes the plot. If data or
analysis settings have been changed since the diagram was last
analyzed, you must reanalyze the data before refreshing the plot.)
You can add additional plot sheets to the diagram by right-clicking
the sheet index tabs at the bottom of the window and choosing
Insert Analytical Plot
on the shortcut menu. You can delete a plot sheet from the diagram
by selecting the plot sheet, right-clicking and choosing Delete Plot.
Note: For fault trees analyzed using the BDD Approximation analysis type, only the two Static Reliability Importance plots are available.
The plots available for analytical diagrams fall into three
types:
System
Plots
System
plots display information about the entire system.
- Unreliability vs.
Time shows the unreliability of the system over
time. The unreliability value provides the probability
that the event (failure) will occur by a specific time.
- Reliability vs.
Time shows the reliability of the system over time.
- pdf Plot shows the
system's probability density function, which illustrates
the behavior of the life distribution function. Direct
probability or reliability values cannot be read from
this plot. The area below the plotted line, starting at
time zero and ending at the value on the x-axis, is the
probability of failure by that time.
- Failure Rate vs.
Time shows the system's failure rate over time.
The failure rate is the number of failures occurring per
unit time.
Metrics
Plots
Metrics plots display information about the reliability
importance of the blocks in the system.
For the RI vs. Time plot and the Static RI plot, to specify
which blocks to include in the plot, you can manually select
blocks in the Available Blocks
area of the control panel. You can sort the list by clicking
the Sort List icon
to open the Sort List window.
Tip:
When you point to the Sort
List icon, a tooltip will appear that shows the current
selections in the Sort List window.
For the Static RI plot, you can also click Select
Blocks by Value to specify the number of blocks to
show in the plot. You can choose to show the blocks with the
largest values or the smallest values.
- RI vs. Time
shows the reliability
importance of the blocks in the system over time.
Reliability importance is a measure of the relative importance
of each component in a system with respect to the overall
reliability of the system.
- Static RI
shows the static reliability importance and the reliability
of a specified number of blocks in the system at a specific
time. Bar size indicates reliability importance; bar color
indicates reliability, as shown in the legend. Point to
a bar to view the block's name, reliability and calculated
importance.
- Static RI Tableau
shows the static reliability importance of the blocks
in the system at a specific time in tableau format, along
with each block's reliability. To view this plot, you
must specify the time at which the reliability values
are calculated. The block name appears on each area of
the plot. The largest sections represent the blocks with
the highest reliability importance; section color indicates
block reliability, as shown in the legend. Point to a
plot section to view the block's name, reliability and
calculated importance.
Note:
The RI vs. Time plot does not include mirror blocks, if there
are any in the simulation. The Static RI and Static RI Tableau
plots will include only the block with the highest importance
from the mirror group.
Blocks
Plots
Blocks plots display information about the individual blocks
that make up the system.
For blocks plots, when you first select the plot, you must
specify which blocks to include by using the Available
Blocks area of the control panel to select which blocks
to view. You can sort the list by clicking the Sort
List icon to open the Sort
List window.
The list order also affects the order in which items are
shown in the plot legend and, therefore, line appearance settings
such as color, which are applied according to the order in
which they appear in the legend.
Tip:
When you point to the Sort
List icon, a tooltip will appear that shows the current
selections in the Sort List window.
You can also view the corresponding system values by selecting
the Show System check
box.
- Block Unreliability
vs. Time shows the unreliability of the selected
blocks plotted against time. The unreliability value provides
the probability that the event (failure) will occur by
a specific time.
- Block Reliability
vs. Time shows the reliability of the selected
blocks plotted against time.
- Block pdf
shows the probability density function of the selected
blocks plotted against time. Direct probability or reliability
values cannot be read from this plot. The area below the
plotted line, starting at time zero and ending at the
value on the x-axis, is the probability of failure by
that time.
- Block Failure Rate
shows the failure rate over time of the selected blocks
plotted against time. The failure rate is the number of
failures occurring per unit time.
Note that confidence bounds are available for the Unreliability
vs. Time, Reliability vs. Time and Failure Rate vs. Time plots
in cases where all blocks that can fail in the diagram use models
that have Fisher matrix bounds. To have Fisher matrix bounds,
a model must have been created by publishing
from a data source, such as a Weibull++ data sheet, that was calculated
using Fisher matrix bounds. Bounds are not available if the diagram has containers or mirrored blocks, or if any block uses the cumulative damage model. Bounds are also unavailable if the diagram has subdiagrams, unless the diagram and all subdiagrams are analytical fault trees using the BDD analysis type. Where applicable,
you can add confidence bounds to a plot by choosing Plot
> Confidence Bounds > Confidence Bounds.