It is worthwhile to suppose that in some cases it may be feasible to put a system
out of operation well prior the income rate drop period. Difference in final effect value
may be detected after simulation of system replacement process prior the first
significant efficiency drop (Fig. 12).
Figure 12. Simulation of a process of the system’s replacement with newer item
As it was previously noted the efficiency may not be regarded as the sole criterion
for technical system lifetime determination.
Various types of failures are possible during technical system operation which
may affect its efficiency. Efficiency decrease caused by such failures is determined by
reliability. Thus, reliability is a more particular characteristic, than efficiency.
Reliability represents a complex feature, which, depending on a purpose of a
technical system and operational conditions may encompass various indicators.
Probability of technical system trouble-free operation under certain conditions is
the most universal reliability characteristic [8]. However, failure term should be
specified to obtain numeric values of reliability indicator. The failure definition allows
a great variety of interpretations. As the components failures accumulate, technical
system’s operational efficiency decreases. Efficiency decrease may take place either
gradually, or show a rapid lapse.
Below essential technical system’s numeric reliability indicators are reviewed.
Suppose, that an individual technical system is represented by n parts or elements,
which may stay in either of two incompatible states – operable (1) and disabled (2). In
this case the technical system’s condition may be described by a certain number of
incompatible conditions N= 2
n
H = {H
m
}, forming a complete group of events and
placed in conditions matrix Н:
t
3
t
2
t
1
t
y.e.
E
1
T
E
2
T
E
3
T
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