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a limiting condition. The resource is expressed in units of time (hours) path
length (kilometers) units of output. For non-repairable products, the concept of
technical resource and time to failure are the same.
Service life – calendar life up to limiting state. Express usually in the years.
For details of mechatronic modules as a criterion for durability of use technical
resource. Durability is divided into gamma-percent average to the current (or
major) repair, complete, average to disposal. They characterize the longevity
of the products for a given probability of preservation of health. For example,
gamma-percent life tγ is the time at which the object will not reach limit state
with given probability at expressed in percentage.
For products of serial and mass production the most often used 90% of
the resource. If the refusal is dangerous to human life, the resource closer to
100%. Maintainability – adaptability of the product to the prevention, detec-
tion and elimination of failures and malfunctions by carrying out maintenance
and repairs. Persistence is a property of the product to preserve the value of
indicators of reliability, durability and maintainability during and after an
established period of storage and transportation.
Indicators of maintainability and persistence. The average time to recover a
healthy state, the shelf life is average and percent.
Comprehensive reliability. Coefficient of technical use – the ratio of
expected uptime for a certain period of operation to the sum of mathematical
expectations of uptime and downtime for all repairs and maintenance.
Availability – the probability that the object will be in working state at any
time, except for periods in which operation is not provided. It is defined as the
ratio of expected time spent in a healthy state to mathematical expectation of
amount of this time and unscheduled repairs.
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