Assessment of the Remaining Service Life of Excavators’ Structural Components at Roşia Poieni Quarry

Abstract This paper presents an integrated analysis of the structural durability of an excavator boom, a critical component subjected to extreme cyclic loads in the harsh mining environment of Roșia Poieni quarry. The study combines a numerical approach based on the Finite Element Method (FEM) with the theoretical principles of fatigue analysis to evaluate the stress state, estimate the remaining service life, and determine the safety factor. The FEM analysis, applied to a hybrid shell-beam model of the Hitachi EX1000 excavator boom, revealed critical stress concentrations in connection and welding zones, confirming these points’ vulnerability to fatigue failure. Based on the stress values extracted from the simulation, Wöhler curve (S-N curve), adjusted with specific environmental (corrosion) and reliability factors, was used to estimate the service life. The results indicated a number of cycles to failure of approximately 3.98×10 4 and an estimated mean time to failure of 4457.14 hours, which signals a high risk of premature failure. A supplementary evaluation using the Goodman diagram confirmed this risk, calculating a safety factor of 1.49, a value below the recommended standards for dynamic applications. The study concludes that the boom operates in a potentially unsafe regime and proposes a series of practical recommendations to improve its reliability. These include implementing Condition-Based Monitoring (CBM) systems, optimizing the structural design in critical areas, and intensifying anti-corrosion protection programs.