Dawit Bogale Alemayehu

Dr. Dawit Bogale Alemayehu

Mechanical Engineering, McGill University, Montréal, Quebec, Canada
Postdoctoral Fellow# McGill University# Mechanical Engineeri...

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 November 2021 in Materials
Verified
Journal Article
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Dawit Bogale AlemayehuDawit Bogale Alemayehu
Dawit Bogale Alemayehu
Yeau-Ren JengYeau-Ren Jeng
Yeau-Ren Jeng
Variations in the implant thread shape and occlusal load behavior may result in significant changes in the biological and mechanical properties of dental implants and surrounding bone tissue. Most previous studies consider a single implant thread design, an isotropic bone structure, and a static occlusal load. However, the effects of different thread designs, bone material properties, and loading conditions are important concerns in clinical practice. Accordingly, the present study performs Finite Element Analysis (FEA) simulations to investigate the static, quasi-static and dynamic response of the implant and implanted bone material under various thread designs and occlusal loading directions (buccal-lingual, mesiodistal and apical). The simulations focus specifically on the von Mises stress, displacement, shear stress, compressive stress, and tensile stress within the implant and the surrounding bone. The results show that the thread design and occlusal loading rate have a significant effect on the stress distribution and deformation of the implant and bone structure during clinical applications. Overall, the results provide a useful insight into the design of enhanced dental implants for an improved load transfer efficiency and success rate.

Verified
Journal Article
Open access
PDF file
Dawit Bogale AlemayehuDawit Bogale Alemayehu
Dawit Bogale Alemayehu
MTMasahiro Todoh
Masahiro Todoh
Bio-inspired gyroid triply periodic minimum surface (TPMS) lattice structures have been the focus of research in automotive engineering because they can absorb a lot of energy and have wider plateau ranges. The main challenge is determining the optimal energy absorption capacity and accurately capturing plastic plateau areas using finite element analysis (FEA). Using nTop’s Boolean subtraction method, this study combined walled TPMS gyroid structures with a normal TPMS gyroid lattice. This made a composite TPMS gyroid lattice (CTG) with relative densities ranging from 14% to 54%. Using ideaMaker 4.2.3 (3DRaise Pro 2) software and the fused deposition modeling (FDM) Raise3D Pro 2 3D printer to print polylactic acid (PLA) bioplastics in 1.75 mm filament made it possible to slice computer-aided design (CAD) models and fabricate 36 lattice samples precisely using a layer-by-layer technique. Shimadzu 100 kN testing equipment was utilized for the mechanical compression experiments. The finite element approach validates the results of mechanical compression testing. Further, a composite CTG was examined using a field emission scanning electron microscope (FE-SEM) before and after compression testing. The composite TPMS gyroid lattice showed potential as shock absorbers for vehicles with relative densities of 33%, 38%, and 54%. The Gibson–Ashby model showed that the composite TPMS gyroid lattice deformed mainly by bending, and the size effect was seen when the relative densities were less than 15%. The lattice’s relative density had a significant impact on its ability to absorb energy. The research also explored the use of these innovative foam-like composite TPMS gyroid lattices in high-speed crash box scenarios to potentially enhance vehicle safety and performance. The structures have tremendous potential to improve vehicle safety by acting as advanced shock absorbers, which are particularly effective at higher relative densities.

13 September 2021 in Preprints.org
Verified
Preprint
Open access
Dawit Bogale AlemayehuDawit Bogale Alemayehu
Dawit Bogale Alemayehu
Yeau-Ren JengYeau-Ren Jeng
Yeau-Ren Jeng
Variations in the implant thread shape and occlusal load behavior may result in significant changes in the biological and mechanical properties of dental implants and surrounding bone tissue. Most previous studies consider a single implant thread design, an isotropic bone structure, and a static occlusal load. However, the effects of different thread designs, bone material properties, and loading conditions are important concerns in clinical practice. Accordingly, the present study performs Finite Element Analysis (FEA) simulations to investigate the static, quasi-static and dynamic response of the implant and implanted bone material under various thread designs and occlusal loading directions (buccal-lingual, mesiodistal and apical). The simulations focus specifically on the von Mises stress, displacement, shear stress, compressive stress and tensile stress within the implant and the surrounding bone. The results show that the thread design and occlusal loading rate have a significant effect on the stress distribution and deformation of the implant and bone structure during clinical applications. Overall, the results provide a useful insight into the design of enhanced dental implants for an improved load transfer efficiency and success rate.

Verified
Journal Article
Open access
PDF file
Dawit Bogale AlemayehuDawit Bogale Alemayehu
Dawit Bogale Alemayehu
MTMasahiro Todoh
Masahiro Todoh
Song-Jeng HuangSong-Jeng Huang
Song-Jeng Huang
Background: Dental implantology has evolved significantly since the introduction of additive manufacturing, which allows for the reproduction of natural bone’s porous architecture to improve bone tissue compatibility and address stress distribution issues important to long-term implant success. Conventional solid dental implants frequently cause stress shielding, which compromises osseointegration and reduces durability. Aim: The current research proposes to examine the biomechanical efficacy of fully and hybrid gyroid triply periodic minimum surface (TPMS) latticed implants across different cell sizes to optimize stress distribution and improve implant durability. Methods: This study evaluates six fully and hybrid gyroid (TPMS) latticed implants, including fully latticed designs with three cell sizes—FLI_111 (1 mm × 1 mm × 1 mm), FLI_222 (2 mm × 2 mm × 2 mm), and FLI_333 (3 mm × 3 mm × 3 mm)—and hybrid gyroid TPMS latticed implants with solid necks in corresponding sizes—HI_111, HI_222, and HI_333. To enhance initial stability, a square-threaded design was added into the bottom part of both fully and hybrid lattice implants. The designs also incorporate anti-rotational connections to enhance fixation, and they undergo a clinical viability comparison with contemporary implants. To improve lattice designs, finite element analysis (FEA) was utilized through nTopology (nTOP 4.17.3) to balance stiffness and flexibility. To examine mechanical performance under realistic conditions, a dynamic mastication loading simulation was conducted for 1.5 s across three cycles. Results: The findings reveal that hybrid implants, particularly HI_222, exhibited improved mechanical characteristics by reducing micromotions at the bone–implant interface, improving osteointegration, and attaining better stress distribution. Conclusions: By addressing stress shielding and boosting implant performance, this work paves the way for personalized implant designs, developing dental technology, and improving clinical results.

Verified
Journal Article
Open access
PDF file
Dawit Bogale AlemayehuDawit Bogale Alemayehu
Dawit Bogale Alemayehu
MTMasahiro Todoh
Masahiro Todoh
Song-Jeng HuangSong-Jeng Huang
Song-Jeng Huang
The human mandible’s cancellous bone, which is characterized by its unique porosity and directional sensitivity to external forces, is crucial for sustaining biting stress. Traditional computer- aided design (CAD) models fail to fully represent the bone’s anisotropic structure and thus depend on simple isotropic assumptions. For our research, we use the latest versions of nTOP 4.17.3 and Creo Parametric 8.0 software to make biomimetic Voronoi lattice models that accurately reflect the complex geometry and mechanical properties of trabecular bone. The porosity of human cancellous bone is accurately modeled in this work using biomimetic Voronoi lattice models. The porosities range from 70% to 95%, which can be achieved by changing the pore sizes to 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm. Finite element analysis (FEA) was used to examine the displacements, stresses, and strains acting on dental implants with a buttress thread, abutment, retaining screw, and biting load surface. The results show that the Voronoi model accurately depicts the complex anatomy of the trabecular bone in the human jaw, compared to standard solid block models. The ideal pore size for biomimetic Voronoi lattice trabecular bone models is 2 mm, taking in to account both the von Mises stress distribution over the dental implant, screw retention, cortical bone, cancellous bone, and micromotions. This pore size displayed balanced performance by successfully matching natural bone’s mechanical characteristics. Advanced FEA improves the biomechanical understanding of how bones and implants interact by creating more accurate models of biological problems and dynamic loading situations. This makes biomechanical engineering better.

18 March 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
Dawit Bogale AlemayehuDawit Bogale Alemayehu
Dawit Bogale Alemayehu
MTMasahiro Todoh
Masahiro Todoh
Bio-inspired gyroid triply periodic minimum surface (TPMS) lattice structures have been the focus of research in automotive engineering because they can absorb a lot of energy and have wider plateau ranges. The main challenge is determining the optimal energy absorption capacity and accurately capturing plastic plateau areas using finite element analysis (FEA). Using nTop's Boolean subtraction method, this study combined walled TPMS gyroid structures with normal TPMS gyroid lattice. This made a composite TPMS-gyroid lattice with relative densities ranging from 14% to 54%. Using the ideaMaker software and the fused deposition modeling (FDM) Raise3D Pro 2 3D printer to print polylactic acid (PLA) bioplastics in 1.75 mm filament made it possible to slice computer aided design (CAD) models and fabricate 36 lattices samples precisely layer by layer technique. Shimadzu 100kN testing equipment was utilized for the mechanical compression experiments. And the validation using finite element analysis (FEA). Further, CTG was examined using a field emission scanning electron microscope (FE-SEM) before and after compression testing. The composite TPMS gyroid lattice showed potential as shock absorbers for vehicles with relative densities of 33%, 38%, and 54%. The Gibson-Ashby model showed that the composite TPMS gyroid lattice deformed mainly by bending, and the size effect was seen when the relative densities were less than 15%. The lattice's relative density had a significant impact on its ability to absorb energy. The research also explored the use of these innovative foam-like composite TPMS-gyroid lattices in high-speed crash box scenarios, potentially enhancing vehicle safety and performance.