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ReliaSoft reference: six systems tested concurrently, equivalent single system and projection to 3,000 h

ToolReliability Growth
SourceReliaSoft Corporation (2015). "Crow-AMSAA (NHPP)." Reliability Growth and Repairable System Analysis Reference, ReliaWiki. Multiple-systems concurrent example.
LevelProfessional

Problem

Six systems were run concurrently on their own clocks for a total of 2,909 hours and 82 failures were recorded with the system and its own time at each failure. Build the equivalent single system, fit the Crow-AMSAA model, and estimate how many more failures to expect if the test is extended to 3,000 total hours.

Inputs to Enter

  • Data format several systems: a line per failure with system and time, plus a line name end T for each system's end time (82 failures, termination 2,909 hours)
  • Future test time 3,000 hours
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Answers

  • Equivalent single system: first events at 42, 126, …, 498, …, 1,386 hours; termination 2,909
  • β̂ = 0.8939, λ̂ = 0.0657; expected failures at 3,000 h = 84.29, about 2.3 (3) more than observed
  • The two-system illustration of the same page (events 30, 50, 94, 124, 160, 178, 210; end 100 + 125 = 225) is reproduced by the small default of the systems format

Notes

Choose the several-systems format; the select loads the two-system illustration, replace it with the 82 rows of the six-system table for this example.

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