Sequential Data with Failure Modes - Logistic Model

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This example appears in the Reliability Growth and Repairable System Analysis Reference.

Consider the data given in the Missile Launch Test example. Now suppose that the engineers assigned failure modes to each failure and that the appropriate corrective actions were taken.

The table below presents the data.

1. Find the Logistic reliability growth curve that best represents the data.
2. Plot it comparatively with the raw data.
3. If design changes continue to be incorporated and the testing continues, when will the reliability goal of 99.50% be achieved?
4. If design changes continue to be incorporated and the testing continues, what will be the attainable reliability at the end of the 35th launch?

Sequential Success/Failure Data with Modes

Launch Number	Result	Mode
1	F	2
2	F	1
3	S
4	F	3
5	F	3
6	S
7	S
8	S
9	F	2
10	S
11	F	1
12	S
13	S
14	S
15	S
16	S
17	S
18	S
19	S
20	S

Solution

1. The next figure shows the entered data and the estimated parameters.
   
   
   
   
2. The next figure displays the Reliability vs. Time plot.
   
   
   
   
3. The next figure displays the launch when the reliability goal of 99.5% will be achieved.
   
   
   
   
4. The last figure displays the reliability after the 35th launch.