Maintenance-Aware Risk Curves: Correcting Degradation Models with Intervention Effectiveness

F.J. Bellido-López, M.A. Sanz-Bobi, A. Muñoz, D. González-Calvo, T. Álvarez Tejedor

Applied Sciences Vol. 15, nº. 20, pp. 10998

Summary:

In predictive maintenance frameworks, risk curves are used as interpretable, real-time indicators of equipment degradation. However, existing approaches generally assume a monotonically increasing trend and neglect the corrective effect of maintenance, resulting in unrealistic or overly conservative risk estimations. This paper addresses this limitation by introducing a novel method that dynamically corrects risk curves through a quantitative measure of maintenance effectiveness. The method adjusts the evolution of risk to reflect the actual impact of preventive and corrective interventions, providing a more realistic and traceable representation of asset condition. The approach is validated with case studies on critical feedwater pumps in a combined-cycle power plant. First, individual maintenance actions are analyzed for a single failure mode to assess their direct effectiveness. Second, the cross-mode impact of a corrective intervention is evaluated, revealing both direct and indirect effects. Third, corrected risk curves are compared across two redundant pumps to benchmark maintenance performance, showing similar behavior until 2023, after which one unit accumulated uncontrolled risk while the other remained stable near zero, reflected in their overall performance indicators (0.67 vs. 0.88). These findings demonstrate that maintenance-corrected risk curves enhance diagnostic accuracy, enable benchmarking between comparable assets, and provide a missing piece for the development of realistic, risk-informed predictive maintenance strategies.

Spanish layman's summary:

Este estudio presenta curvas de riesgo sensibles al mantenimiento que integran la eficacia real de las acciones preventivas y correctivas. Al corregir dinámicamente indicadores de riesgo derivados de desviaciones monitorizadas, el método mejora el diagnóstico y la planificación predictiva.

English layman's summary:

This study introduces maintenance-aware risk curves that integrate the real effectiveness of preventive and corrective actions. By dynamically correcting risk indicators derived from monitored deviations, the method improves diagnosis, benchmarking, and predictive maintenance.

Keywords: risk curves; predictive maintenance (PdM); maintenance effectiveness; Condition-Based Monitoring (CBM); Prognosis and Health Management (PHM); power plant pumps; reliability engineering

JCR-JIF Impact Factor and WoS quartile: 2,900 - Q2 (2025)

DOI reference: https://doi.org/10.3390/app152010998

Published on paper: October 2025.

Published on-line: October 2025.

Citation:
F.J. Bellido-López, M.A. Sanz-Bobi, A. Muñoz, D. González-Calvo, T. Álvarez Tejedor, "Maintenance-Aware Risk Curves: Correcting Degradation Models with Intervention Effectiveness", Applied Sciences, Vol. 15, nº. 20, pp. 10998, October 2025. [Online: October 2025] doi: 10.3390/app152010998