4.3 Average Unit Cost for Repairs of the Subsystem
Eq (10) expresses the dependency of the average unit cost
for repairs of a subsystem upon its operating time. A graph of
the function cR (t) shown in Fig. 2 intersects the co-ordinate
origin and it increases within the whole scope of studied
values of operating time of functions. This interpretation is
rather simplified because a real course of the function
cR (t) usually includes three different parts – running in, phase
of constant failure rate a phase of wear-out failures.
A possible actual course of the function cR (t) is depicted in
Fig. 3.