Maintenance strategies for wind turbines: from reliability modelling to economic evaluation of preventive maintenance optimization and the transition to predictive maintenance Youssef Sadraoui, Mohamed Er-Ratby, Moulay Saddik Kadiri, Abdessamad Kobi Journal of Quality in Maintenance Engineering, 2026 Purpose This study aims to evaluate and enhance maintenance strategies for wind turbines by transitioning from conventional fixed interval preventive maintenance to optimized and predictive maintenance approaches, with the goal of improving reliability and reducing operational costs. Design/methodology/approach The research utilizes real failure data from critical wind turbine components (shaft, gearbox and generator) and models their reliability using Normal, Lognormal and Weibull distributions. Monte Carlo simulations are conducted to analyse system failure behaviour under different maintenance strategies (conventional and optimized preventive maintenance). Additionally, a detailed cost-benefit and return on investment analysis is performed to assess the financial feasibility of predictive maintenance implementation, considering various real-time condition monitoring technologies. Findings Results show that fixed interval preventive maintenance leads to unnecessary maintenance interventions and increased downtime, particularly for components with non-uniform failure patterns. Optimized preventive maintenance, guided by reliability thresholds, significantly reduces redundant maintenance, while predictive maintenance, using vibration monitoring, oil particle detection and thermal analysis, further lowers operational costs, extends component lifespans and minimizes production losses. Return on investment analysis confirms the long-term economic viability of predictive maintenance, despite challenges such as high initial costs and sensor reliability in harsh environments. The transition from regular to optimized preventive maintenance and ultimately to predictive maintenance significantly increases wind turbine reliability and reduces downtime, intervention frequency and maintenance costs. Originality/value This study provides a comprehensive, data-driven framework that bridges reliability modelling with practical maintenance planning in wind energy. It uniquely combines simulation, statistical modelling and financial analysis to demonstrate the transformative potential of predictive maintenance for more sustainable, efficient and cost-effective wind turbine management.
Improving measurement system fidelity through the optimization of preventive maintenance and operating conditions: a comparative study of measurement system analysis approaches Youssef Sadraoui, Mohamed Er-Ratby, Moulay Saddik Kadiri, Abdessamad Kobi Engineering Research Express, 2025 This study focused on measurement system analysis MSA through gage of Repeatability and Reproducibility R and R methods (Average and Range Xbar/R, Analysis Of Variance ANOVA, Evaluating Measurement Process EMP III) to verify the accuracy and precision of a laser diffraction particle size analyser used to monitor particles’ size in wet grinding process, this device gained great faith in many researches without checking its fidelity. The initial evaluation demonstrates the measurement system’s unacceptability, driving to establish an improvement plan including preventive maintenance scheduling for the instrument to maintain it in good working conditions and anticipate futures anomalies that could affect the measurement system fidelity, standardization of measuring process by the instrument to reduce repeatability, which was found to be the largest source of variation in the gage R and R analysis affecting measurement accuracy and precision, along with unifying the method of calculating solid rate percentage of samples before measurements because it is a significant factor that can affect the measurement results, finally, operators training to conduct measurements in the same way and following unified procedures in the purpose of minimizing reproducibility and increasing the measurement system fidelity, which is proven by the final results. Along this evaluation, a critical comparison between these techniques is conducted in terms of calculations, result’s interpretation and acceptability requirements to evaluate the efficiency of each method. Xbar/R and ANOVA demonstrate a similarities in interpretation and acceptability criteria but ANOVA surpassed Xbar/R by adding new factors in the calculations, while EMP III, which is not widely addressed in the literature, shows a great difference with a distinguished methodology, distinct metrics and acceptability guidelines. Therefore, a combination of ANOVA and EMP III in measurement system analysis would be very effective by extracting comprehensive informations about the studied instrument.
Improving wind turbine reliability through the analysis of critical component failures, parametric modelling, and maintenance optimization Youssef Sadraoui, Mohamed Er-ratby, Moulay Saddik Kadiri, Abdessamad Kobi Wind Engineering, 2025 This study conducts a reliability analysis of a wind turbine system, focusing on shaft, gearbox, and generator. The goal is to evaluate their time between failures and determine the most suitable statistical models to describe their failure behaviours. Four distributions (3-parameter Weibull, 2-parameter exponential, normal, and 3-parameter lognormal) were assessed using maximum likelihood and least squares estimation with goodness-of-fit tests including Anderson-Darling (ADC) and Pearson correlation coefficients (PCC). Results show that gearbox is best modelled by 3-parameter lognormal, while generator fits the 3-parameter Weibull. The shaft yielded contradictory outcomes between ADC and PCC, which were resolved through Akaike and Bayesian information criterions implemented in Python, confirming the normal distribution as optimal. Reliability differences were evident with gearbox exhibited infant mortality and highest failure rates, shaft showed wear-out behaviour and generator demonstrated reliable and stable behaviour. These findings highlight the importance of component-specific modelling to optimize maintenance, reliability and system lifespan.
Thermodynamic study and modeling of the speciation and behavior of cadmium in the PO₄–SO₄–Ca–Cd–H₂O system using the Pitzer model R Belkhair, FE Baali, L Khamar, MS Kadiri Journal of Molecular Liquids 455, 129571 , 2026 2026
Thermodynamic Modeling and Experimental Investigation of Phosphoric Acid as a Polyelectrolyte System: Comparative Assessment of Thermodynamic Models R Belkhair, L Khamar, FE Baali, MS Kadiri EPJ Web of Conferences 371, 05004 , 2026 2026
Study and Optimization of Cadmium Content Reduction in Phosphoric Acid Profiles Titrating from 7% to 31% P₂O₅ Using a Response Surface Approach R Belkhair, L Khamar, T Mahloub, FE Baali, MS Bargani Moroccan Journal of Chemistry 14 (1), J. Chem. 14 (1)-109 , 2026 2026
Experimental Study and Thermodynamic Modeling of Cadmium Behavior in the PO₄–SO₄–Ca–Cd–H₂O System Using the Extended Debye–Hückel Model R Belkhair, L Khamar, F ezzahra Baali, R Chatit, MS Kadiri Chemical Thermodynamics and Thermal Analysis, 100258 , 2025 2025 Citations: 1
A numerical analysis of air flow topology within a vertical channel attached behind photovoltaic panel H El Kharaz, K Khallaki, MS Kadiri, K Choukairy International Journal of Heat and Mass Transfer 223, 125254 , 2024 2024 Citations: 10
Enhancing tablet manufacturing efficiency through numerical simulation and modeling of pharmaceutical powder compaction: a comprehensive review S Ramli, MS Kadiri International Conference on Advanced Intelligent Systems for Sustainable … , 2023 2023 Citations: 2
Rheological behaviour modelling of phosphoric acid produced from Moroccan phosphate rocks A Boukhsib, L Khamar, MS Kadiri, K Khallaki, L Omari Indian Chemical Engineer 65 (1), 14-24 , 2023 2023 Citations: 5
A hybrid algorithm using the FEM-MESHLESS method to solve nonlinear structural problems R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Engineering Analysis with Boundary Elements 140, 531-543 , 2022 2022 Citations: 14
A meshfree method based on weak-strong form for structural analysis R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Structural Engineering and Mechanics, 651-664 , 2022 2022 Citations: 6
Performance’s improvement methods of PV solar panel by different cooling systems: a review of experimental and numerical studies H El Kharaz, K Khallaki, MS Kadiri, K Choukairy AIP Conference Proceedings 2345 (1), 020039 , 2021 2021 Citations: 24
Process for Reducing the magnesium content in industrial phosphoric acid by its precipitation to magnesium fluorosilicate A Boukhsib, L Khamar, MS Kadiri, L Omari magnesium 2 (P2O5), 1 , 2021 2021 Citations: 4
Meshless approach based on MLS with additional constraints for large deformation analysis R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Journal of Physics: Conference Series 1743 (1), 012015 , 2021 2021 Citations: 2
A coupled Meshless-FEM method based on strong form of Radial Point Interpolation Method (RPIM) R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Journal of Physics: Conference Series 1743 (1), 012039 , 2021 2021 Citations: 5
Preface: The 6th International Congress on Thermal Sciences (AMT’2020) K Choukairy 2020
Numerical study on a porous material subject to SiC particles deposition, using OpenFOAM and sensitivity analysis technique: effect of clogging evolution on the thermal … SA Abed, A Settar, K Chetehouna, MS Kadiri, E El Tabach, N Gascoin Chemical Engineering Science 212, 115321 , 2020 2020 Citations: 23
Effects of magnesium content on the rheological behaviour of phosphoric acid and on the performances of his industrial manufacturing by the dihydrate wet processes A Boukhsib, L Khamar, MS Kadiri, L Omari International Journal of Engineering Sciences & Research Technology 8 (7), 1-14 , 2019 2019 Citations: 9
Experimental transient clogging of brass porous disks by silicium particles S Akridiss, E El Tabach, K Chetehouna, N Gascoin, MS Kadiri Experimental Thermal and Fluid Science 98, 112-120 , 2018 2018 Citations: 5
Experimental study of flow effects of solid particles’ size in porous media S Akridiss, E El Tabach, K Chetehouna, N Gascoin, MS Kadiri 20th International Conference on Experimental Heat Transfer, Fluid Mechanics … , 2018 2018
Numerical modeling of combustion chamber material permeability change S Akridiss, E El Tabach, K Chetehouna, N Gascoin, MS Kadiri Aerospace Science and Technology 78, 553-558 , 2018 2018 Citations: 12
Modélisation de l’écoulement multiphasique dans un milieu poreux–Application au phénomène du cokage et son impact sur le refroidissement d’une paroi poreuse MS Kadiri, S Akridiss, K Chetehouna, E El Tabach, N Gascoin 5ième Congrès International de Thermique–AMT’2018 , 2018 2018
MOST CITED SCHOLAR PUBLICATIONS
Wall friction in the compaction of pharmaceutical powders: measurement and effect on the density distribution A Michrafy, JA Dodds, MS Kadiri Powder Technology 148 (1), 53-55 , 2004 2004 Citations: 98
Predictions of tensile strength of binary tablets using linear and power law mixing rules A Michrafy, M Michrafy, MS Kadiri, JA Dodds International journal of Pharmaceutics 333 (1-2), 118-126 , 2007 2007 Citations: 85
The effect of punch's shape on die compaction of pharmaceutical powders MS Kadiri, A Michrafy Powder Technology 239, 467-477 , 2013 2013 Citations: 72
Wall friction and its effects on the density distribution in the compaction of pharmaceutical excipients A Michrafy, MS Kadiri, JA Dodds Chemical Engineering Research and Design 81 (8), 946-952 , 2003 2003 Citations: 63
Pharmaceutical powders compaction: Experimental and numerical analysis of the density distribution MS Kadiri, A Michrafy, JA Dodds Powder Technology 157 (1-3), 176-182 , 2005 2005 Citations: 57
Performance’s improvement methods of PV solar panel by different cooling systems: a review of experimental and numerical studies H El Kharaz, K Khallaki, MS Kadiri, K Choukairy AIP Conference Proceedings 2345 (1), 020039 , 2021 2021 Citations: 24
Numerical study on a porous material subject to SiC particles deposition, using OpenFOAM and sensitivity analysis technique: effect of clogging evolution on the thermal … SA Abed, A Settar, K Chetehouna, MS Kadiri, E El Tabach, N Gascoin Chemical Engineering Science 212, 115321 , 2020 2020 Citations: 23
The effects of ambient temperature on the compaction of pharmaceutical powders A Michrafy, S Haas, MS Kadiri, K Sommer, JA Dodds Proceedings of the Institution of Mechanical Engineers, Part E: Journal of … , 2006 2006 Citations: 15
A hybrid algorithm using the FEM-MESHLESS method to solve nonlinear structural problems R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Engineering Analysis with Boundary Elements 140, 531-543 , 2022 2022 Citations: 14
Numerical modeling of combustion chamber material permeability change S Akridiss, E El Tabach, K Chetehouna, N Gascoin, MS Kadiri Aerospace Science and Technology 78, 553-558 , 2018 2018 Citations: 12
Compression de poudres pharmaceutiques et interaction avec l'outillage. Analyse expérimentale et modélisation numérique MS Kadiri Toulouse, INPT , 2004 2004 Citations: 11
A numerical analysis of air flow topology within a vertical channel attached behind photovoltaic panel H El Kharaz, K Khallaki, MS Kadiri, K Choukairy International Journal of Heat and Mass Transfer 223, 125254 , 2024 2024 Citations: 10
Effects of magnesium content on the rheological behaviour of phosphoric acid and on the performances of his industrial manufacturing by the dihydrate wet processes A Boukhsib, L Khamar, MS Kadiri, L Omari International Journal of Engineering Sciences & Research Technology 8 (7), 1-14 , 2019 2019 Citations: 9
A meshfree method based on weak-strong form for structural analysis R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Structural Engineering and Mechanics, 651-664 , 2022 2022 Citations: 6
Compression de poudres pharmaceutiques et interaction avec l'outillage MS Kadiri Institut National Polytechnique (Toulouse) , 2004 2004 Citations: 6
Rheological behaviour modelling of phosphoric acid produced from Moroccan phosphate rocks A Boukhsib, L Khamar, MS Kadiri, K Khallaki, L Omari Indian Chemical Engineer 65 (1), 14-24 , 2023 2023 Citations: 5
A coupled Meshless-FEM method based on strong form of Radial Point Interpolation Method (RPIM) R El Kadmiri, Y Belaasilia, A Timesli, MS Kadiri Journal of Physics: Conference Series 1743 (1), 012039 , 2021 2021 Citations: 5
Experimental transient clogging of brass porous disks by silicium particles S Akridiss, E El Tabach, K Chetehouna, N Gascoin, MS Kadiri Experimental Thermal and Fluid Science 98, 112-120 , 2018 2018 Citations: 5
Modeling and Simulation of a Water Gas Shift Reactor operating at a low pressure W El Bazi, A El-Abidi, MS Kadiri, S Yadir International Journal of Innovation Engineering and Science Research 2, 47-57 , 2018 2018 Citations: 5
Process for Reducing the magnesium content in industrial phosphoric acid by its precipitation to magnesium fluorosilicate A Boukhsib, L Khamar, MS Kadiri, L Omari magnesium 2 (P2O5), 1 , 2021 2021 Citations: 4