Optimum inspection interval for hidden functions during extended life
نویسندگان
چکیده
Notation and Acronyms α scale parameter β shape parameter φ demand rate for the hidden function per hour CA cost of an accident CI cost of inspection COC opportunity cost of lost production Cr cost of repair CRep cost of Discard FFI Failure Finding Inspection F(t) unreliability function FN(t) conditional probability of failure within the N extended FFI Fk(t) conditional probability of failure within the k scheduled FFI h(t) rate of occurrence of failure (ROCOF) H(t) cumulative ROCOF K Number of scheduled FFI interval MFDT Mean Fractional Dead Time N number of extended FFI cycles R(t) reliability function t local time within N inspection cycle T inspection interval TI inspection time TK scheduled discard life with TK=TS.K TN extended life for discard (postponement period) with TN=TP.N TP FFI interval for the extended life period TR repair time TS original scheduled FFI interval
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