PSI - Issue 20

V.I. Kuksova / Procedia Structural Integrity 20 (2019) 98–102

99

2

V.I. Kuksova / Structural Integrity Procedia 00 (2019) 000 – 000

1. Introduction The development of technical diagnostics, transformation of the systems of technical diagnostics (STD) to the integral element of complex technical systems (CTS) demanded a research of problems of efficiency of STD, assessment of their influence on production characteristics, safety and stability of the object of diagnostics (OD). The efficiency of STD depends on a number of factors; their action is defined by characteristics of the applied means of technical diagnosing, ability of an object to diagnosing, diagnostic providing (parameters of concrete STD), etc.

Nomenclature τ

the diagnosing period

I STD ( τ ) EF STD ( τ ) EF 0 ( τ ) STD ( τ )

index of effectiveness of a system of diagnosing

index of efficiency of an object of diagnostics with the system of diagnosing index of efficiency of an object of diagnostics without the system of diagnosing indexes, characterizing efficiency of an object with the system of diagnosing indexes of efficiency of an object without the system of diagnosing

k i k i a i n

0

weight coefficients of the corresponding characteristics

number of accepted indexes, characterizing efficiency of the object of diagnostics F ( a i k i STD ( τ )) function of the efficiency of an object of diagnostics with the system of diagnosing F ( a i k i 0 ( τ )) function of the efficiency of an object of diagnostics without the system of diagnosing R opt

functional determining the decreasing in an accident risk and risk from operation of OD as a result of functioning of STD

D 1 ( R ) D 2 ( R )

reduced cost of creation and functioning of STD direct losses caused by risk of accident (refusal) of STD

When determining efficiency of STD it is necessary to consider two aspects of assessment of effectiveness (efficiency) of technical diagnosing: assessment of the impact of STD on results of functioning of an object of diagnostics. assessment of effectiveness (quality) of functioning of STD itself. Diagnosing is an integral part of the processes of service of CTS, that’s why the indexes characterizing reliability and non-failure operation of their functioning, can be at the same time both STD and OD indexes. That’s why it is difficult to separate some attributes of the system of technical diagnostics and the object of diagnostics from each

other, and in a sense such division has conditional character. 2. Quantitative assessment of results of functioning of STD

Quantitative assessment of results of functioning of STD is important for practical purposes. In a general view, assessment of the impact of STD on results of functioning of OD can be received by comparison of indexes of efficiency of an object of diagnostics without the system of diagnosing EF 0 ( τ ) and with the system of diagnosing EF STD ( τ ). The index of effectiveness of a system of diagnosing I STD ( τ ) can be written as Gumenyuk (2010):

STD

o

( )

( )

( ) EF F a k (

( ))

( F a k i i

( )),

1,

I

EF

i

n .

(1)

0

STD

STD

i i

Assessment of effectiveness of functioning of STD itself is made on the basis of indexes of quality of technical diagnosing, which, as a rule, are the following by Akhmetkhanov et al. (2016): 1. The duration of the technical diagnosing (time interval necessary for carrying out diagnosing of an object). 2. The reliability of diagnosing, estimated by the degree of objective compliance of results of diagnosing to the real