Haievskyi S. Mathematical models and methods for extending the residual life of the aircraft radioelectronic system

Українська версія

Thesis for the degree of Doctor of Philosophy (PhD)

State registration number


Applicant for


  • 275 - Транспорт. Транспортні технології (за видами)


Specialized Academic Board

ДФ 23.144.002

Flight Academy of National Aviation University


The dissertation solves an urgent scientific problem, which was to substantiate and develop models and methods for calculating the final resource of the radioelectronic system (RES) of the aircraft, which will reduce the current cost of aircraft maintenance while ensuring failure-free and safe operation of the aircraft. The general provisions on calculation of indicators of residual resource of the aircraft RES which make a methodical basis of a calculation technique and include the hierarchical scheme of calculation, procedure of division of functional systems, functional knots and structural products into non-renewable and renewable objects with full, minimum or incomplete restorations are developed; the procedure for developing new or using known mathematical models of failure and recovery processes for relevant objects; general provisions on the assessment of the technical condition and substantiation of the signs of the limit states of the aircraft RES, other general provisions, are developed. It is shown that the assessment of the limit states of the aircraft RES should be carried out on a set of indicators that reflect the state of components, functional units and systems, components of the RES, cable products, materials, accessories and their reliability. A generalization of the known mathematical models of the failure rate of components with an unlimited number of minimal restorations of finite duration is obtained. Mathematical models of the flow of failures of the structural products of the circuit position with a finite number of restorations of different depth during the assigned service life are considered; the expediency of their use in the calculation of residual life is shown. The concept of residual life and residual operating time for renewable products and the corresponding indicators of residual life and residual operating time are introduced. Mathematical models for calculation of indicators of residual resource and residual operating time of the restored product with one resource element at finite number of full or minimum restorations of accessories are considered. Generalizations of these models for a renewable product with several resource elements are obtained. The calculated relations for the indicators of residual resource and residual operating time of functional units and systems at a finite number of minimal renewals of resource elements are obtained. The technique of calculation of indicators of reliability of the restored functional unit and system of the aircraft RES on the extended interval of operation taking into account resource restoration (in full, incomplete or zero volume) at current repair only at a replaceable or renewable component and invariance of a resource of other elements of knot or system is offered. Features of calculation of indicators of residual operating time of the aircraft RES, its functional systems are considered. Two schemes of approximate calculation using structural schemes of reliability; using the method of phase aggregation of states are offered. Appropriate mathematical models are developed and the dependences of the relative error of calculations of the value of the nonstationary coefficient on the number of functional systems, the level of their reliability, operating time are investigated. It is shown that the accuracy of calculations of residual life indicators is determined by the accuracy of estimating the moment of aging of the aircraft RES, the accuracy of regression line estimation for the failure rate parameter, the accuracy of cost indicators for operating the aircraft RES and other indicators. The calculated ratios for estimating the errors in the calculation of durability indicators are obtained. The calculated ratios for estimating the cost of operation of the aircraft RES, which provide calculations of cost-effective service life and decision-making to continue operation, repair or decommissioning of the aircraft, are suggested. The application of the proposed technique of calculating of the indicators of residual life is effective for the aircraft RES as a whole and its functional systems, according to which operation may accumulate the necessary amount of statistical information to build regression dependences of failure rate and recovery intensity over time with acceptable accuracy and reliability. The developed methodical apparatus allows to solve a number of actual tasks of prolongation of a resource of the aircraft RES, for example: to form set of signs of limit states of the aircraft RES for an estimation of their condition on places of operation; to carry out calculations of indicators of residual resource of the aircraft RES for decision-making on extension of resources, on carrying out of tests of leading aircraft on an estimation of indicators of residual resource, for a substantiation of volumes of tests; substantiate the need for additional tests of individual functional systems, components, test volumes, etc.


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