Evaluating the elastic properties of ensete fiber as a sustainable alternative to bast fibers: A micromechanical and numerical study Barati Kelefatshe, Nonofo Emily Ramothokgwana, Mesfin Belayneh Ageze, Migbar Assefa Zeleke Engineering Solid Mechanics, 2026 Bast fibers are promising natural materials known for their biodegradability, affordability, and eco-friendliness, making them an alternative to synthetic options. Extensive research has been conducted to examine the effects of integrating various bast fiber reinforcements into epoxy and polystyrene matrices to boost the properties of the composite materials. However, there is limited research on ensete fiber and its utilization as a reinforcement that needs more in-depth research to be used as an alternative bast fiber. This paper aimed to predict and compare the performance of ensete fiber composites with six other bast fiber-reinforced polystyrene and epoxy composites. In this study, flax, hemp, jute, ramie, banana and kenaf were selected bast fibers for comparison purposes. This article employed various micromechanics models and finite element method (FEM), varying the fiber volume fraction. Our findings revealed that hemp fiber-reinforced composites exhibited the best predicted elastic properties, while banana fiber-reinforced composites showed the weakest performance. Notably, composites made with ensete fibers outperformed those made with jute and banana fibers in both epoxy and polystyrene matrices. Comparisons were made between results from the micromechanics models and FEM for all bast fiber-reinforced epoxy and polystyrene composites and there was an agreement between the effective elastic properties and fiber volume fraction (FVF). Further, bast-fiber reinforced epoxy composites showed higher values than polystyrene for strain analysis while for stress analysis, polystyrene composites showed higher stress loads than epoxy composites.
Exploring stress intensity factor computation: A parametric study using extended isogeometric analysis (XIGA) M. A. Zeleke, Mesfin Belayneh Ageze, Ntirelang Robert Batane, Edward Dintwa Engineering Solid Mechanics, 2025 The permanence and durability of mechanical and structural elements with discontinuities such as cracks and voids require the calculation of SIF (stress intensity factors) with reasonable fidelity. SIF is a crucial parameter that predicts crack growth and failure behavior by quantifying the stress field neighboring the crack tip. Therefore, understanding the sophisticated characteristics of the stress fields in the vicinity of discontinuity requires an effective way of calculating SIFs. Currently, there are numerous methods to calculate SIF, such as FVM (Finite Volume Method), FEM (Finite Element Method), BEM (Boundary Element Method), XFEM (Extended Finite Element Method), Phase field method and Meshfree methods. For an extended period, FEM is one of the leading methods in solving fracture mechanics problems. Though FEM is quite robust in dealing with several engineering problems, it has got its inherent drawbacks to deal with singular fields like discontinuities. Hence to reasonably capture moving discontinuities, finer meshes near the discontinuous field are required that demand more computation effort and time. To alleviate the above drawback of FEM, this study employed Extended Isogeometric Analysis (XIGA) to efficiently and effectively determine the SIFs in the case of fissured plates as benchmarking fissure problems. In this study SIFs in relation to crack length were examined for edge and center cracked plates and results were compared with the theoretical values.
Perspectives of Vertical Axis Wind Turbines in Cluster Configurations Ryan Randall, Chunmei Chen, Mesfin Belayneh Ageze, Muluken Temesgen Tigabu Fluid Dynamics and Materials Processing, 2024 Vertical Axis Wind Turbines (VAWTs) offer several advantages over horizontal axis wind turbines (HAWTs), including quieter operation, ease of maintenance, and simpli fi ed construction. Surprisingly, despite the prevailing belief that HAWTs outperform VAWTs as individual units, VAWTs demonstrate higher power density when arranged in clusters. This phenomenon arises from positive wake interactions downstream of VAWTs, potentially enhancing the overall wind farm performances. In contrast, wake interactions negatively impact HAWT farms, reducing their ef fi ciency. This paper extensively reviews the potential of VAWT clusters to increase energy output and reduce wind energy costs. A precise terminology is introduced to clarify ambiguous terms researchers use to quantify cluster parameters. While examining commonly studied and proposed VAWT cluster con fi gurations, several aspects are discussed such as aerodynamic interactions, wake characteristics, structural dynamics, and performance metrics. Additionally, the current state-of-the-art and research gaps are critically described. The review also covers computational modeling, optimization techniques, advanced control strategies, machine learning applications, economic considerations, and the in fl uence of terrain and application locations.
Adama II wind farm long-term power generation forecasting based on machine learning models Solomon Terefe Ayele, Mesfin Belayneh Ageze, Migbar Assefa Zeleke, Temesgen Abriham Miliket Scientific African, 2023 The present article develops time series machine learning models to forecast the Adama II wind farm's long-term power production using SCADA data. The study applied data from the previous six years (2016 to 2021) with five years of data for training the model and the remaining one year for testing and validation. The study compares six supervised learning algorithms: elastic net regression, random forest regression, SARIMA, and XGBoost. The projections for the 1-hour, 1-week, and 12-month forecasting ranges are compared for each forecasting model. The findings demonstrate that SARIMAX models outperform other models for forecasting one hour and one week, with a result of a 90% of R2 score and a 24% mean absolute percentage error (MAPE). However, XGBoost (with Fourier terms for seasonality) provides the foremost long-term forecasting result which is 7.33% MAPE for yearly prediction. Moreover, a combined Prophet and XGBoost for year-ahead wind power predictions has yield superior performance when compared to using each model individually which is 6.9%MAPE. Hence, for wind farms such as Adama II's long-term power forecasting, a combined prophet and XGBoost model fits well and provides accurate power generation insight.
Experimental characterizations of hybrid natural fiber-reinforced composite for wind turbine blades Temesgen Abriham Miliket, Mesfin Belayneh Ageze, Muluken Temesgen Tigabu, Migbar Assefa Zeleke Heliyon, 2022 Performances of hybrid Natural Fiber-Reinforced Composites (NFRCs) from E-glass, Nacha (Hibiscus macranthus Hochst. Ex-A. Rich.), and Sisal (Agave sisalana) fibers are investigated for wind turbine blades applications. The process of composite manufacturing was getting started with harvesting and extracting the fibers from undesired constituents. To improve the interfacial interaction between fibers, it was further treated with 5% of NaOH and remnants removal. The experiment was performed based on the Taguchi method, specifically with L16 orthogonal array. Four levels of a natural fiber weight ratio (i.e. 5%, 10%, 15 %, and 20%) were considered during the composite preparations process while the weight of glass fiber was maintained at 5% and 10%. The composites are manufactured using the hand lay-up method, and the test specimens are as per American Society for Testing and Materials (ASTM) standards. Then, tensile, compressive, and flexural tests were carried out using a universal testing machine (UTM). Analysis of variance (ANOVA) was employed to determine the factors which affect the experimental responses. Hence, in the main effect, it was confirmed that Nacha fiber (%wt of N) significantly contributes to tensile, compressive, and flexural strength at a 95% level of confidence. Furthermore, the optimal fiber compositions of composites are determined based on a higher signal-to-noise ratio (S/N) for the corresponding strengths.
Aerodynamic performance enhancement and computational methods for H-Darrieus vertical axis wind turbines: Review Temesgen Abriham Miliket, Mesfin Belayneh Ageze, Muluken Temesgen Tigabu International Journal of Green Energy, 2022 The wind is one of the most promising green energy resources that replenishes itselves in less than a human lifetime without depleting the planet’s resources. According to the disposition of the blade concerning the shaft, wind turbine can be classified as horizontal axis wind turbine (HAWT) and vertical axis wind turbine (VAWT). In contrast to VAWT, HAWT covers most commercial installations around the globe. However, VAWTs became a promising alternative for areas far away from grid-connected electricity, they have certain drawbacks associated with aerodynamic performance. The present work overviews the magnitude of factors affecting the aerodynamics of typical VAWT, i.e H-Darrieus VAWT and enhancement options associated with cutting edge performance. Additionally, the accuracy of the turbine performance predicting tools through computational investigation and optimization was also assessed. Therefore, the review covered the factors that altered the turbine performance and viable enhancement options studied in the existing literature. Finally, FSI simulation was tics of materials commonly used for turbine blade manufacturing. It was determined that the computational tools employed significantly influence the accuracy of the model, and proper model selection and more experimental validations are compulsory. It was determined that the computational tools employed significantly influence the accuracy of the model, and proper model selection and more experimental validations are compulsory.
A Review of Peridynamics (PD) Theory of Diffusion Based Problems Migbar Assefa Zeleke, Mesfin Belayneh Ageze Journal of Engineering United Kingdom, 2021 The study of heat conduction phenomena using peridynamic (PD) theory has a paramount significance on the development of computational heat transfer. This is because PD theory has got an interesting feature to deal with the inherent nonlocal nature of heat transfer processes. Since the revolutionary work on PD theory by Silling (2000), extensive investigations have been devoted to PD theory. This paper provides a survey on the recent developments of PD theory mainly focusing on diffusion based peridynamic (PD) formulation. Both the bond-based and state-based PD formulations are revisited, and numerical examples of two-dimensional problems are presented.
Comparative study on uni-and bi-directional fluid structure coupling of wind turbine blades Mesfin Ageze, Yefa Hu, Huachun Wu Energies, 2017 The current trends of wind turbine blade designs are geared towards a longer and slender blade with high flexibility, exhibiting complex aeroelastic loadings and instability issues, including flutter; in this regard, fluid-structure interaction (FSI) plays a significant role. The present article will conduct a comparative study between uni-directional and bi-directional fluid-structural coupling models for a horizontal axis wind turbine. A full-scale, geometric copy of the NREL 5MW blade with simplified material distribution is considered for simulation. Analytical formulations of the governing relations with appropriate approximation are highlighted, including turbulence model, i.e., Shear Stress Transport (SST) k-ω. These analytical relations are implemented using Multiphysics package ANSYS employing Fluent module (Computational Fluid Dynamics (CFD)-based solver) for the fluid domain and Transient Structural module (Finite Element Analysis-based solver) for the structural domain. ANSYS system coupling module also is configured to model the two fluid-structure coupling methods. The rated operational condition of the blade for a full cycle rotation is considered as a comparison domain. In the bi-directional coupling model, the structural deformation alters the angle of attack from the designed values, and by extension the flow pattern along the blade span; furthermore, the tip deflection keeps fluctuating whilst it tends to stabilize in the uni-directional coupling model.
Exploring stress intensity factor computation: A parametric study using extended isogeometric analysis (XIGA) ED Migbar Assefa Zeleke, Mesfin Belayneh Ageze, Ntirelang Robert Batane Engineering Solid Mechanics 13 (1), 125-140 , 2025 2025
Perspectives of peridynamic theory in wind turbines computational modeling MB Ageze, MA Zeleke, TA Miliket, M Ngoepe Archives of Computational Methods in Engineering 32 (1), 1-33 , 2025 2025 Citations: 1
Perspectives of Vertical Axis Wind Turbines in Cluster Configurations. C Chen, MB Ageze, MT Tigabu Fluid Dynamics & Materials Processing 20 (12) , 2024 2024 Citations: 11
Adama II wind farm long-term power generation forecasting based on machine learning models ST Ayele, MB Ageze, MA Zeleke, TA Miliket Scientific African 21, e01831 , 2023 2023 Citations: 26
Aerodynamic performance enhancement and computational methods for H-Darrieus vertical axis wind turbines TA Miliket, MB Ageze, MT Tigabu International Journal of Green Energy 19 (13), 1428-1465 , 2022 2022 Citations: 34
Experimental characterizations of hybrid natural fiber-reinforced composite for wind turbine blades TA Miliket, MB Ageze, MT Tigabu, MA Zeleke Heliyon 8 (3) , 2022 2022 Citations: 57
Advances of Science and Technology: 9th EAI International Conference, ICAST 2021, Hybrid Event, Bahir Dar, Ethiopia, August 27–29, 2021, Proceedings, Part I ML Berihun Springer Nature , 2022 2022 Citations: 5
A Review of Peridynamics (PD) Theory of Diffusion Based Problems M Assefa Zeleke, M Belayneh Ageze HINDAWI , 2021 2021
Numerical Investigations of Variable Pitch Straight-Bladed H-Darrieus VAWT TA Miliket, MB Ageze, MT Tigabu International Conference on Advances of Science and Technology, 565-583 , 2021 2021 Citations: 2
Acknowledgment to Reviewers of Fluids in 2020 Fluids Editorial Office Fluids 6 (1), 45 , 2021 2021
Acknowledgment to Reviewers of Fluids in 2020 N Abbas, OA Azarova, S Abdallah, A Azevedo, SI Abdelsalam, ... 2021
A review of peridynamics (PD) theory of diffusion based problems MA Zeleke, MB Ageze Journal of Engineering 2021 (1), 7782326 , 2021 2021 Citations: 16
Principles of Aeroelasticity AR Ghasemi, MB Ageze 2019
Comparative study on uni-and bi-directional fluid structure coupling of wind turbine blades MB Ageze, Y Hu, H Wu Energies 10 (10), 1499 , 2017 2017 Citations: 18
Wind turbine aeroelastic modeling: basics and cutting edge trends MB Ageze, Y Hu, H Wu International Journal of Aerospace Engineering 2017 (1), 5263897 , 2017 2017 Citations: 50
DESIGN AND MANUFACTURING OF DIRECT DRIVEN STANDALONE WIND ENERGY CONVERSION SYSTEM M BELAYNEH 2011
MOST CITED SCHOLAR PUBLICATIONS
Experimental characterizations of hybrid natural fiber-reinforced composite for wind turbine blades TA Miliket, MB Ageze, MT Tigabu, MA Zeleke Heliyon 8 (3) , 2022 2022 Citations: 57
Wind turbine aeroelastic modeling: basics and cutting edge trends MB Ageze, Y Hu, H Wu International Journal of Aerospace Engineering 2017 (1), 5263897 , 2017 2017 Citations: 50
Aerodynamic performance enhancement and computational methods for H-Darrieus vertical axis wind turbines TA Miliket, MB Ageze, MT Tigabu International Journal of Green Energy 19 (13), 1428-1465 , 2022 2022 Citations: 34
Adama II wind farm long-term power generation forecasting based on machine learning models ST Ayele, MB Ageze, MA Zeleke, TA Miliket Scientific African 21, e01831 , 2023 2023 Citations: 26
Comparative study on uni-and bi-directional fluid structure coupling of wind turbine blades MB Ageze, Y Hu, H Wu Energies 10 (10), 1499 , 2017 2017 Citations: 18
A review of peridynamics (PD) theory of diffusion based problems MA Zeleke, MB Ageze Journal of Engineering 2021 (1), 7782326 , 2021 2021 Citations: 16
Perspectives of Vertical Axis Wind Turbines in Cluster Configurations. C Chen, MB Ageze, MT Tigabu Fluid Dynamics & Materials Processing 20 (12) , 2024 2024 Citations: 11
Advances of Science and Technology: 9th EAI International Conference, ICAST 2021, Hybrid Event, Bahir Dar, Ethiopia, August 27–29, 2021, Proceedings, Part I ML Berihun Springer Nature , 2022 2022 Citations: 5
Numerical Investigations of Variable Pitch Straight-Bladed H-Darrieus VAWT TA Miliket, MB Ageze, MT Tigabu International Conference on Advances of Science and Technology, 565-583 , 2021 2021 Citations: 2
Perspectives of peridynamic theory in wind turbines computational modeling MB Ageze, MA Zeleke, TA Miliket, M Ngoepe Archives of Computational Methods in Engineering 32 (1), 1-33 , 2025 2025 Citations: 1
Exploring stress intensity factor computation: A parametric study using extended isogeometric analysis (XIGA) ED Migbar Assefa Zeleke, Mesfin Belayneh Ageze, Ntirelang Robert Batane Engineering Solid Mechanics 13 (1), 125-140 , 2025 2025
A Review of Peridynamics (PD) Theory of Diffusion Based Problems M Assefa Zeleke, M Belayneh Ageze HINDAWI , 2021 2021
Acknowledgment to Reviewers of Fluids in 2020 Fluids Editorial Office Fluids 6 (1), 45 , 2021 2021
Acknowledgment to Reviewers of Fluids in 2020 N Abbas, OA Azarova, S Abdallah, A Azevedo, SI Abdelsalam, ... 2021
Principles of Aeroelasticity AR Ghasemi, MB Ageze 2019
DESIGN AND MANUFACTURING OF DIRECT DRIVEN STANDALONE WIND ENERGY CONVERSION SYSTEM M BELAYNEH 2011
