PSI - Issue 81

Dmytro Voloshyn et al. / Procedia Structural Integrity 81 (2026) 228–233

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individual components, regulatory and technical requirements, statistics on the reliability of technological equipment and parts, etc. The FMECA methodology can be used to classify failures in the production system (Table 4) and to develop measures for their further elimination. The proposed approach features the identification of the so-called critical production elements or critical technological processes. The critical elements and processes include those affecting the production environment and, thus, leading to a failure of the overall system, which makes it impossible to fulfill the production task. The FMECA procedure ranks all potential failures by two characteristics: intensity/frequency of failure and effect value. A qualitative assessment of criticality of a failure for a production system’s element can be defined as follows:

(1)

n К К К К     ... 1 2

where K n is the criticality index of a failure (in points).

Table 4. An example of the production system failure classification. Type of failure Failure Characteristic І Very significant

may cause nonfulfillment or a failure to perform the work on time

II

Significant Boundary

may cause significant material damage or serious product defects that lead to a failure to complete the task may cause minor material damage or a defect that results in a violation of time standards or substandard repairs does not cause material damage; requires unscheduled maintenance or repair

ІІІ

IV

Insignificant

In the study it was proposed to use a cause-and-effect analysis to obtain complete information on the behaviour of the production system over time and potential scenarios for the development of its states. The special feature is an integrated approach based on the combined use of two well-known methods, fault tree and event tree. The analysis was carried out from the selected critical event using logical elements to reduce the effects of the initial event. At the same time, this approach makes it possible to include time delays while analysing potential consequences. The analysis had the following steps: ● determining the critical (initial) event in the production system, which is the end event for the fault tree and the initial event for the event tree; ● building a corresponding fault tree to determine the causes of a significant failure of the production system; ● defining an algorithm to analyse the system states, such as the logical sequence of their occurrence in time; ● building potential scenarios of effects depending on different states; and ● calculating probabilities of each potential effect. The initial data for the cause-and-effect analysis of a production system are a schematic representation of how the system can fail and a quantitative assessment of the probability of each possible effect. The assessment is based on the analysis of the probabilities of occurrence of specific conditions for each scenario following the critical event. 3. Conclusions 1. An analysis of the producti on system for wagon repair enterprises in today’s environment was carried out. It was concluded that higher reliability in production processes can be achieved through better control. 2. The stochastic conditions under which wagon repair enterprises work require new approaches for production management. The risk assessment and analysis system can be used at wagon repair enterprises to ensure the required efficiency of wagon repairs across all enterprise subsystems at minimal cost to all resources. 3. The examples of how to use certain risk assessment indicators in the production system were presented, and their quantitative characteristics were determined. 4. To formalise the cause-and-effect relationships that cause the occurrence of various types of failures in a production system and affect the overall probability of risks, it is possible to use FMECA (Failure Mode, Effects and Criticality Analysis). A combined method of cause-and-effect analysis can be used as a source of initial data. 5. The risk assessment system will allow for continuous monitoring of potential undesirable events in the system, with the consequence of minimising material losses from them. References

Aulin, V., Lyashuk, O., Pavlenko, O., Velykodnyi, D., Hrynkiv, A., Lysenko, S,, Holub D., Vovk Y., Dzyura, V., Sokol, M., 2019. Realization of the logistic approach in the international cargo delivery system Communications - Scientific Letters of the University of Žilina 21(2), 3 – 12.