−
+
−
−
=
k
n
fs
t
t
n
T
fs
fs
r
Ï
r
r
r
À
T
1
1
,
(7)
with n
r
– number of undergone repairs (integer value).
r
r
t
T
n=
, (8)
If the repair cost value is not a specific value but depends, for instance, on
automation level of repairing yard and may either exceed or be lower than a certain
fixed value, it may be taken into account applying formula (9) below,
−
+
−
−
+
=
k
n
fs
t
t
n
T
fs
fs
fs
r
Ï
r
r
r
À
r
T
1
1
2
,
(9)
Functional condition of replaceable repairable elements is reviewed below.
Replaceable repairable elements represent a general case of the elements which
have been reviewed above. This group of elements may be subject both to
reconditioning and replacement, as and when required, throughout the system
operation.
Graphic interpretation of the functional condition of such elements is displayed
below (Fig. 5).
Graphic interpretation of the functional condition of such elements is displayed
below (Fig. 5).
Figure 5. Functional condition alteration of replaceable repairable element
throughout its operation Т
If the system operation time exceeds the element’s term of operation, the
element’s passive state should be reconditioned and its functional condition, contrary
to irreplaceable repairable elements will experience alteration, as follows,
Т
fs
0
FS
T
t
FS
t
s
fs
p
fs
А
t
р
- 1647 -