[分享]Reliability词汇- 4 (27Jul'04)

Maintainablity: the probability that when maintenance action is initiated under stated conditions, a failed system will be restored to operable condition within a specified total downtime.

Maintenance: All actions necessary for retaining an item in or restoring it to a specified conditions.

Maintenance, corrective: all actions performed as a result of failure to restore an item to a specified condition. Corrective maintenance can include any or all of the following steps: localization, isolation, disassembly, interchange, reassembly, alignment and checkout.

Maintenance, preventive: A procedure of periodically reconditoning a product in accordance with specific deterioration while the product is in service. this type of maintenance may be either schedured or nonscheduled in nature.

maintenance, scheduled: preventive maintenance preformed at prescribed points in an item's life.

Mainenance, unscheduled: corrective maintenance required by item conditions.

Malfunction: Unsatisfactory operation of a device because of one or more faults.

Mean life: the arithmethic mean of the times that a group of nominally identical items spend before they cease to function permanently. This may include seveal cycles of failures and repairs in the case of repairable items.

Mean life, assessed: the mean life of a non-repaired item determined within stated confidence limits from the observed mean life or nominally identical items. Alternatively, point estimates may be used, the basis of which must be defined.

Mean life, predicted(for non-repaired items): the product of the number of items and their operating time divided by the total estimated number of failures.

Mean time between failures, assessed: the mean time between failures of a repairable item determined within stated confidence limits from the observed mean time between failures of nominally identical items. Alternatively, point estimates may be used, the basis of which must be defined.

Mean time between failures, predicted: the mean time between failures of a repairable complex item computed from its design considerations and from the failure rates of its parts under the intended conditionsof use. The method used for the calculation, the basis of the extrapolation and the time-stress conditions should be stated.

Mean time to failure (for non-repairable items): the total operating time of a number of items divided by total number of failures.

Mean time to failure, assessed: the mean time to failure of a non-repairable item determined within stated confidence limits from the observed mean time to failure of nominally identical items. Alternatively, point estimates may be used, the basis of which must be defined.

Mean time to failure, observed(for non-repairable items): for truncated tests for a particular period, the total cumulative observed time on a population divided by the total number of failures during the period under stated stress conditions.(1) cumulative observed time is a product of units and time or the sum of these products. (2) The criteria for what constitutes a failure should be stated.

Mean time to failure, predicted: the mean time to failure of a non-repairable comlex item computed from its design considerations and from the failure rates of its parts for the intended conditions of use. The method used for the calculation, the basis of the extrapolation, and the time-stress conditions should be stated.


MTBF(mean time between failures): the average time an item logs in operating between its two successive failures. This is often used in the context of repairable items.

MTTF(mean time to failure): the total operating time of a number of items divied by the total number of items.

MTTR(mean time to repair): the average time taken to repair an item

MTTFT(mean time to first failure): mean time interval from the system initiation to the first smiystem failure.

Mission time: the period fo time in which a device must perform a mission udner the specified operating condition.

Operating time: the period during which the item (system) is operating in a manner acceptable to the operator.

Operational readiness: the probability that, at any point in time, the system is either operating or ready to be placed in operation on demand when used under stated conditions.

Operational time: that interval during which the equipment is in actual operation. this tiem is basis to reliability. Operational time is really a category related to equipment condition.

Path set: a set of elements whose functioning ensures the system success.

Path set, minimal: set of elements which has no proper subset whose functioning alone would ensure the system success..