Chymshyr
V.
Doctor of Technical Sciences, Professor, Director of Danube Institute of the
National University “Odesa Maritime Academy”, Izmail, Ukraine
SYSTEM’S TECHNICAL CONDITION ASSESSMENT METHOD AND
DETERMINATION OF ITS OPERATION TIMEFRAME IN UNCERTAINTY
CONDITIONS
Introduction. Assessment of technical system functionality, including
operational stability and reparability level in the context of uncertainty occupies a
special place in technical system’s general assessment [1]. Operational and
maintenance indicators characterizing technical system may include term of operation,
capacity, operation expenditures, repair costs, frequency and costs of repairs, etc. As a
matter of fact, operation of a particular technical system often requires realistic forecast
of operation and repair characteristics to enable planning of its activity and efficient
functioning.
As a result of processing data obtained in works [2 through 7] and by other authors
certain conclusions have been drawn. One of them, in particular, enables to state that
most of them proclaim that technical condition of actually any particular technical
system experiences step changes with obvious consistent patterns and service time in
the course of operation. Some examples are given below.
Modeling of railway cars’ maintenance reviewed in the work [6], to the author’s
opinion may consist in pattern identification between a railway car technical condition
and operation terms with reference to probable accidental damage caused by decrease
in railway cars’ technical condition level in the course of their operation.
If a railway car’s technical condition is determined by a sole factor К (0 < К≤1),
the alteration of this factor as time goes (К(х)), since manufacturing and putting into
operation may be approximately expressed with a function, as below [6]:
()
(
)
a
in
x
T
b
K
K
x
K
−
−
−
=
1
,
where Kin – a value of a railway car’s technical condition factor immediately after
its manufacturing and putting into operation (Kin = 1); ΔК – allowable limit of the К
factor decrease in the course of operation; b and a – factors determined applying an
experimental methods as a result of inspection of a sufficiently numerous quantity of
railway cars; Т
1
– initial term of operation, х – running time in years.
The obtained resulting railway car’s technical condition alteration pattern in the
course of time is represented in Fig. 1.
A system’s functional condition (summarized service features characteristic)
means its relative capability and potential ability to perform its functions or a specified
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