PSI - Issue 81

Andrii Gypka et al. / Procedia Structural Integrity 81 (2026) 478–485

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range of stabilization of the maximum CER R value and the minimum μ value, as well as an increase in CER R by 10 – 20 times in the pressure range of 2 – 10 MPa. The final stage of the experimental investigations involved determining the influence of the universal additive Anglamol 99 added to diesel fuel on the behavior of CER R and μ as a function of contact pressure P for the steel 30Kh3MFSA – steel 30Kh3MFSA tribological pair (Fig. 10)

Fig. 10. Graphs of the dependence of the friction coefficient μ and contact electrical resistance R for the steel 30Kh3MFSA – steel 30Kh3MFSA tribological pair on contact pressure P in pure diesel fuel and diesel fuel with Anglamol 99 additive.

With the use of pure diesel fuel, increasing the contact pressure P from zero to 2.5 MPa reduces CER R from 40 Ω to 10 Ω, and with a further increase in pressure to 5 MPa, CER R rises to 30 Ω. In the pressure range of 5 – 12.5 MPa, CER R gradually decreases to 10 Ω and then falls to zero at a contact pressure of 17.5 MPa. When diesel fuel with the Anglamol 9 9 additive is used, the initial increase in contact pressure from 0 to 2 MPa causes CER R to decrease from 35 Ω to 3 Ω, and in the pressure range of 2 – 5 MPa its value increases smoothly to 8 Ω. A further small increase in pressure to 6 MPa causes a sharp r ise in CER R to 1750 Ω and stabilizes within one hour of friction machine operation, which is 70 times higher compared to pure diesel fuel. Increasing the contact pressure to 14 MPa results in CER R reaching 7500 Ω after 25 minutes of testing. Increasing t he contact pressure to 17.5 MPa does not significantly affect CER R . Regarding the behavior of the friction coefficient μ under similar test conditions in both lubricating environments, no significant differences were observed over the entire loading range. In these experiments, due to the large range of CER R variation, the KSP 4 scale is logarithmic. The maximum CER R value and the minimum μ value and their stabilization over the entire investigated loading range indicate the effective influence of the Anglamol 99 additive on friction and wear processes in the frictional contact zone of the tribological pair. Summarizing the obtained experimental results and analyzing the behavior of CER R and μ as well as DSS characteristics and their correlation, it is confirmed that CER R is structurally more sensitive and more informative than μ with respect to the kinetics of DSS formation, transformation and destruction processes. The experimental feasibility and efficiency of CER R measurement for evaluating the kinetics of friction and wear processes is evidenced by the fact that approximately 10 hours of friction machine operation are required to construct a CER R =f( V ) graph at constant P (Fig. 6) based on its stabilized values and determine the ranges of normal mechano-chemical and thermo-chemical processes for a single friction pair (one experiment), whereas to determine the wear rate only at one fixed value of P and V within these process ranges requires about 200 hours of machine operation. The reason is the high wear resistance of the tested specimens (minimal I), therefore long test duration is required to accumulate measurable wear considering the metrological characteristics of existing measuring equipment (in this case, analytical balance VLR-200). 3. Conclusions The operational reliability of the designed and manufactured friction testing machine with high stiffness of the friction unit and loading mechanism has been confirmed during tribological studies, which ensured objective, well-reproducible and comparable results, essential for expanding the tribotechnical data bank. The feasibility of using the contact electrical resistance (CER, R ) parameter of tribological pairs to evaluate the kinetics of friction and wear processes has been substantiated. Experimental data have been obtained on the influence of sliding speed and contact pressure over wide ranges under their smooth variation on the values and behavior of key tribotechnical parameters, CER R , and the structural condition of the friction surfaces of tribological components. A correlation relationship has been identified between the main tribotechnical parameters, CER R , and DSS type within normal friction and wear regimes for different investigated materials and lubricating environments. The high tribological informativeness of CER R has been confirmed and the effectiveness of its use in studying processes in the frictional contact zone has been justified. A rapid diagnostic method has been developed to determine the ranges of normal friction and wear, running-in processes, and transition to damage onset based on the values and behavior of CER R of tribological pairs.