# Relibilty Engineering Problem — Duane Parameters Essay Example

RELIABILITY ENGINEERING PROBLEM- DUANE PARAMETERS

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Data with 12 failures

1. Reliability growth

Given that is time for failures and the number of failures, then

Mean time between failures ( ) is given as  Therefore making the equation algebraic: Setting    Then, Equating to the expected value, Assuming a constant failure intensity, the cumulative intensity Then, Therefore, the total expected failures at   Duane reliability,  Where T = test time Time at beginning of monitoring period Cumulative MTBF at start of monitoring period   = growth rate = instantaneous MTBF

Cumulative failure rate is expressed as  = initial failure rate ) , the test time = growth rate = 0.4701    Figure 1: Estimated Duane parameters

1. Cumulative and instantaneous MTBF curves Figure 2: Cumulative MTBF vs Time Figure 3: instantaneous MTBF vs Time Figure 4: Cumulative and instantaneous MTBF curves

1. Required time for instantaneous MTBF of 500hours MTBF  1. Required time for cumulative MTBF of 500hours References