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This example validates the results for test-fix-find-test data in RGA.
Reference Case
MIL-HDBK-189A, Section 7.5.2, pg. 206, 2009.
For this example, the following will be calculated:
- Parameters of the Crow Extended model
- Demonstrated MTBF (DMTBF)
- BD mode parameters
- Projected MTBF (PMTBF)
Data
The following table shows the data.
| Failure Time
|
Classification Mode
|
| 0.7 |
BC1
|
| 3.7 |
BC1
|
| 13.2 |
BC1
|
| 15 |
BD1
|
| 17.6 |
BC2
|
| 25.3 |
BD2
|
| 47.5 |
BD3
|
| 54 |
BD4
|
| 54.5 |
BC3
|
| 56.4 |
BD5
|
| 63.6 |
A
|
| 72.2 |
BD5
|
| 99.2 |
BC4
|
| 99.6 |
BD6
|
| 100.3 |
BD7
|
| 102.5 |
A
|
| 112 |
BD8
|
| 112.2 |
BC5
|
| 120.9 |
BD2
|
| 121.9 |
BC6
|
| 125.5 |
BD9
|
| 133.4 |
BD10
|
| 151 |
BC7
|
| 163 |
BC8
|
| 164.7 |
BD9
|
| 174.5 |
BC9
|
| 177.4 |
BD10
|
| 191.6 |
BC10
|
| 192.7 |
BD11
|
| 213 |
A
|
| 244.8 |
A
|
| 249 |
BD12
|
| 250.8 |
A
|
| 260.1 |
BD1
|
| 263.5 |
BD8
|
| 271.1 |
A
|
| 274.7 |
BD6
|
| 282.8 |
BC11
|
| 285 |
BD13
|
| 304 |
BD9
|
| 315.4 |
BD4
|
| 317.1 |
A
|
| 320.6 |
A
|
| 324.5 |
BD12
|
| 324.9 |
BD10
|
| 342 |
BD5
|
| 350.2 |
BD3
|
| 355.2 |
BC12
|
| 364.6 |
BD10
|
| 364.9 |
A
|
| 366.3 |
BD2
|
| 373 |
BD8
|
| 379.4 |
BD14
|
| 389 |
BD15
|
| 394.9 |
A
|
| 395.2 |
BD16
|
Termination Time = 400 hours
| BD Mode
|
EF
|
| 1 |
0.67
|
| 2 |
0.72
|
| 3 |
0.77
|
| 4 |
0.77
|
| 5 |
0.77
|
| 6 |
0.87
|
| 7 |
0.92
|
| 8 |
0.50
|
| 9 |
0.85
|
| 10 |
0.89
|
| 11 |
0.70
|
| 12 |
0.63
|
| 13 |
0.64
|
| 14 |
0.72
|
| 15 |
0.69
|
| 16 |
0.46
|
Result
The book has the following results:
- Beta = 0.9103, Lambda = 0.2397
- BD Mode Parameters: Beta = 0.7472, Lambda = 0.1820
Results in RGA
In RGA, the Crow Extended model with the maximum likelihood estimation (MLE) method was used to calculate the results.
- The model parameters are:
- The PMTBF is 11.29 hours, as shown in the plot:
