Research Assistants
Res. Assist. İsmail Gürkan Demirkıran

Educational Background
B.Sc. Eskişehir Osmangazi University, Mechanical Engineering, 2014
M.Sc. İzmir Institute of Technology, Energy Engineering, 2020
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Energy Storage
- Passisve Thermal Management
- Medium/High Temperature Phase Change Materials (PCM)
- Computational Fluid Dynamics (CFD)
- +90 232 750 6744
- +90 232 750 6701
- Mechanical Engineering Building, Heat and Mass Transfer Research Lab. (142)
2021 |
Demirkiran, Ismail Gurkan; Cetkin, Erdal Emergence of rectangular shell shape in thermal energy storage applications: Fitting melted phase changing material in a fixed space Journal Article JOURNAL OF ENERGY STORAGE, 37 , 2021. @article{WOS:000641410200002, title = {Emergence of rectangular shell shape in thermal energy storage applications: Fitting melted phase changing material in a fixed space}, author = {Ismail Gurkan Demirkiran and Erdal Cetkin}, doi = {10.1016/j.est.2021.102455}, year = {2021}, date = {2021-05-01}, journal = {JOURNAL OF ENERGY STORAGE}, volume = {37}, abstract = {Here we document the effect of heat transfer fluid (HTF) tube position and shell shape on the melting time and sensible energy requirement for melting a phase change material (PCM) in a multitube latent heat thermal energy storage (LHTES) application. Tube location and shell shape are essential as the shape of the melted region, i.e. similar to the boundary layer, affects convective heat transfer performance. HTF tube total area is fixed in all cases to have the same amount of PCM. In order to eliminate the effect of heat transfer surface area variation, results of two- and four-tube configurations were compared within themselves. Liquid fraction, sensible enthalpy content, and latent/sensible enthalpy ratio relative to time were documented for two and four HTF configurations in various shell shape and tube locations. Results show that eccentric two tubes with rectangular shell decreases melting time and sensible energy requirement from 67 min to 32 min and from 161.8 kJ/kg to 136.3 kJ/kg for 72.3% liquid fraction, respectively, in comparison to the concentric tubes with the circular shell. When the number of HTF tubes increases to four, then the required melting time and sensible energy decrease 80% and 3.8%, respectively, for PCM to melt completely as the concentric tubes and circular shell is replaced with eccentric tubes and rectangular shell. Results of liquid fraction variation relative to time show that S-curve of melting becomes steeper if PCM distribution is such that the intersection of melted regions is delayed. Therefore, melted PCM regions could be packed into a shell that minimizes melting time and required sensible energy. Even rectangular shell shape increases the heat transfer surface (increased heat loss rate) because melting time has decreased greatly, total energy lost to the ambient from the surfaces of shell decreases. Eccentricity slows down the solidification process but due to increased heat loss rate from the surface, rectangular shell enables faster solidification than circular shell shape. There is a trade off in between solidification time and heat loss energy for rectangular channels which can be optimized by selecting proper insulation thickness. Overall, the results show that without any thermal conductivity enhancement (TCE) method, melting performance and latent heat storage capability can be significantly enhanced as decreasing the sensible heat storage by fitting the melted PCM regions into a fixed space for the applications where charging speed is lot faster than discharging.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Here we document the effect of heat transfer fluid (HTF) tube position and shell shape on the melting time and sensible energy requirement for melting a phase change material (PCM) in a multitube latent heat thermal energy storage (LHTES) application. Tube location and shell shape are essential as the shape of the melted region, i.e. similar to the boundary layer, affects convective heat transfer performance. HTF tube total area is fixed in all cases to have the same amount of PCM. In order to eliminate the effect of heat transfer surface area variation, results of two- and four-tube configurations were compared within themselves. Liquid fraction, sensible enthalpy content, and latent/sensible enthalpy ratio relative to time were documented for two and four HTF configurations in various shell shape and tube locations. Results show that eccentric two tubes with rectangular shell decreases melting time and sensible energy requirement from 67 min to 32 min and from 161.8 kJ/kg to 136.3 kJ/kg for 72.3% liquid fraction, respectively, in comparison to the concentric tubes with the circular shell. When the number of HTF tubes increases to four, then the required melting time and sensible energy decrease 80% and 3.8%, respectively, for PCM to melt completely as the concentric tubes and circular shell is replaced with eccentric tubes and rectangular shell. Results of liquid fraction variation relative to time show that S-curve of melting becomes steeper if PCM distribution is such that the intersection of melted regions is delayed. Therefore, melted PCM regions could be packed into a shell that minimizes melting time and required sensible energy. Even rectangular shell shape increases the heat transfer surface (increased heat loss rate) because melting time has decreased greatly, total energy lost to the ambient from the surfaces of shell decreases. Eccentricity slows down the solidification process but due to increased heat loss rate from the surface, rectangular shell enables faster solidification than circular shell shape. There is a trade off in between solidification time and heat loss energy for rectangular channels which can be optimized by selecting proper insulation thickness. Overall, the results show that without any thermal conductivity enhancement (TCE) method, melting performance and latent heat storage capability can be significantly enhanced as decreasing the sensible heat storage by fitting the melted PCM regions into a fixed space for the applications where charging speed is lot faster than discharging. |
Res. Assist. Mehmet Fırat Deniz

Educational Background
B.Sc. İzmir Institute of Technology, Mechanical Engineering, 2023
M.Sc. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Robotics
- +90 232 750 6751
- +90 232 750 6701
- Mechanical Engineering Building, Robotics Lab. (Z30)
- GCRIS Profile
Res. Assist. Fırat Kara

Educational Background
B.Sc. Pamukkale University, Mechanical Engineering, 2013
M.Sc. Van Yüzüncü Yıl University, Mechanical Engineering, 2019
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Mechanisms
- Dynamic Analysis and Control of Mechanisms
- +90 232 750 6752
- +90 232 750 6701
- Mechanical Engineering Building, Rasim Alizade Mechatronics Lab. (Z31)
Res. Assist. Ahmet Devlet Özçelik

Educational Background
B.Sc. TOBB University of Economics and Technology, Mechanical Engineering Department, 2018
M.Sc. Gebze Technical University, Mechanical Engineering, 2023
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Gas Turbines
- Artificial Intelligence
- +90 232 750 6718
- +90 232 750 6701
- Mechanical Engineering Building, Fluid Mechanics Lab. (Z64)
Res. Assist. Merve Özkahya

Educational Background
B.Sc. İzmir Institute of Technology, Mechanical Engineering, 2016
M.Sc.İIzmir Institute of Technology, Mechanical Engineering, 2019
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Mechanism Science
- Dynamics of Machinery
- Balancing of Mechanisms
- +90 232 750 6752
- +90 232 750 6701
- Mechanical Engineering Building, Rasim Alizade Mechatronics Lab. (Z31)
2017 |
Kiper, Gokhan; Dede, Mehmet Ismet Can; Maaroof, Omar W; Ozkahya, Merve Function generation with two loop mechanisms using decomposition and correction method Journal Article MECHANISM AND MACHINE THEORY, 110 , pp. 16-26, 2017, ISSN: 0094-114X. @article{ISI:000394063500002, title = {Function generation with two loop mechanisms using decomposition and correction method}, author = {Gokhan Kiper and Mehmet Ismet Can Dede and Omar W Maaroof and Merve Ozkahya}, doi = {10.1016/j.mechmachtheory.2016.12.004}, issn = {0094-114X}, year = {2017}, date = {2017-04-01}, journal = {MECHANISM AND MACHINE THEORY}, volume = {110}, pages = {16-26}, abstract = {Method of decomposition has been successfully applied to function generation with multi-loop mechanisms. For a two-loop mechanism, a function y = f(x) can be decomposed into two as w = g(x) and y = h(w) = h(g(x)) = f(x). This study makes use of the method of decomposition for two loop mechanisms, where the errors from each loop are forced to match each other. In the first loop, which includes the input of the mechanism, the decomposed function (g) is generated and the resulting structural error is determined. Then, for the second loop, the desired output of the function (f) is considered as an input and the structural error of the decomposed function (g) is determined. By matching the obtained structural errors, the final error in the output of the mechanism is reduced. Three different correction methods are proposed. The first method has three precision points per loop, while the second method has four. In the third method, the extrema of the errors from both loops are matched. The methods are applied to a Watt II type planar six-bar linkage for demonstration. Several numerical examples are worked out and the results are compared with the results in the literature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Method of decomposition has been successfully applied to function generation with multi-loop mechanisms. For a two-loop mechanism, a function y = f(x) can be decomposed into two as w = g(x) and y = h(w) = h(g(x)) = f(x). This study makes use of the method of decomposition for two loop mechanisms, where the errors from each loop are forced to match each other. In the first loop, which includes the input of the mechanism, the decomposed function (g) is generated and the resulting structural error is determined. Then, for the second loop, the desired output of the function (f) is considered as an input and the structural error of the decomposed function (g) is determined. By matching the obtained structural errors, the final error in the output of the mechanism is reduced. Three different correction methods are proposed. The first method has three precision points per loop, while the second method has four. In the third method, the extrema of the errors from both loops are matched. The methods are applied to a Watt II type planar six-bar linkage for demonstration. Several numerical examples are worked out and the results are compared with the results in the literature. |
Res. Assist. Batuhan Özkurt

Educational Background
B.Sc. Yıldız Technical University, Mechatronics Engineering Department, 2022
M.Sc.İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Control
- +90 232 750 6795
- +90 232 750 6701
- Mechanical Engineering Building, Human-Robot Interaction Lab. (Z56)
Res. Assist. Erkan Paksoy

Educational Background
B.Sc. İzmir Institute of Technology, Mechanical Engineering, 2018
M.Sc. İzmir Institute of Technology, Mechanical Engineering, 2022
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Robotics and Control
- Stiffness Analysis of Mechanisms
- +90 232 750 6744
- +90 232 750 6701
- Mechanical Engineering Building, Heat and Mass Transfer Research Lab. (142)
2025 |
Paksoy, Erkan; Dede, Mehmet Ismet Can; Kiper, Gökhan Enhancing trajectory-tracking accuracy of high-acceleration parallel robots by predicting compliant displacements Journal Article 2025. @article{Paksoy2025, title = {Enhancing trajectory-tracking accuracy of high-acceleration parallel robots by predicting compliant displacements}, author = {Erkan Paksoy and Mehmet Ismet Can Dede and Gökhan Kiper}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85214919621&doi=10.1017%2fS0263574724002042&partnerID=40&md5=7bf7b46e48dd5459d472e74e623f469a}, doi = {10.1017/S0263574724002042}, year = {2025}, date = {2025-01-01}, abstract = {For precision-required robot operations, the robot's positioning accuracy, repeatability, and stiffness characteristics should be considered. If the mechanism has the desired repeatability performance, a kinematic calibration process can enhance the positioning accuracy. However, for robot operations where high accelerations are needed, the compliance characteristics of the mechanism affect the trajectory-tracking accuracy adversely. In this paper, a novel approach is proposed to enhance the trajectory-tracking accuracy of a robot operating at high accelerations by predicting the compliant displacements when there is no physical contact of the robot with its environment. Also, this case study compares the trajectory-tracking characteristics of an over-constrained and a normal-constrained 2-degrees-of-freedom (DoF) planar parallel mechanism during high-acceleration operations up to 5 g accelerations. In addition, the influence of the end-effector's center of mass (CoM) position along the normal of the plane is investigated in terms of its effects on the proposed trajectory-enhancing algorithm. © The Author(s), 2025. Published by Cambridge University Press.}, keywords = {}, pubstate = {published}, tppubtype = {article} } For precision-required robot operations, the robot's positioning accuracy, repeatability, and stiffness characteristics should be considered. If the mechanism has the desired repeatability performance, a kinematic calibration process can enhance the positioning accuracy. However, for robot operations where high accelerations are needed, the compliance characteristics of the mechanism affect the trajectory-tracking accuracy adversely. In this paper, a novel approach is proposed to enhance the trajectory-tracking accuracy of a robot operating at high accelerations by predicting the compliant displacements when there is no physical contact of the robot with its environment. Also, this case study compares the trajectory-tracking characteristics of an over-constrained and a normal-constrained 2-degrees-of-freedom (DoF) planar parallel mechanism during high-acceleration operations up to 5 g accelerations. In addition, the influence of the end-effector's center of mass (CoM) position along the normal of the plane is investigated in terms of its effects on the proposed trajectory-enhancing algorithm. © The Author(s), 2025. Published by Cambridge University Press. |
Res. Assist. Umut Ege Samancıoğlu

Educational Background
B.Sc. İzmir Institute of Technology, Mechanical Engineering, 2014
M.Sc. İzmir Institute of Technology, Mechanical Engineering, 2023
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Micromixers
- CFD
- +90 232 750 6744
- +90 232 750 6701
- Mechanical Engineering Building, Heat and Mass Transfer Research Lab. (142)
2025 |
Aydın, Sevgi; Samancıoğlu, Umut Ege; Savcı, İsmail Hakkı; Yiğit, Kadri Süleyman; Çetkin, Erdal Impact of Cooling Strategies and Cell Housing Materials on Lithium-Ion Battery Thermal Management Performance Journal Article 18 (6), 2025. @article{Aydın2025, title = {Impact of Cooling Strategies and Cell Housing Materials on Lithium-Ion Battery Thermal Management Performance}, author = {Sevgi Aydın and Umut Ege Samancıoğlu and İsmail Hakkı Savcı and Kadri Süleyman Yiğit and Erdal Çetkin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-105001137038&doi=10.3390%2fen18061379&partnerID=40&md5=96e267c1fe7da5f9c62ba926f86f7063}, doi = {10.3390/en18061379}, year = {2025}, date = {2025-01-01}, volume = {18}, number = {6}, abstract = {The transition to renewable energy sources from fossil fuels requires that the harvested energy be stored because of the intermittent nature of renewable sources. Thus, lithium-ion batteries have become a widely utilized power source in both daily life and industrial applications due to their high power output and long lifetime. In order to ensure the safe operation of these batteries at their desired power and capacities, it is crucial to implement a thermal management system (TMS) that effectively controls battery temperature. In this study, the thermal performance of a 1S14P lithium-ion battery module composed of cylindrical 18650 cells was compared for distinct cases of natural convection (no cooling), forced air convection, and phase change material (PCM) cooling. During the tests, the greatest temperatures were reached at a 2C discharge rate; the maximum module temperature reached was 55.4 °C under the natural convection condition, whereas forced air convection and PCM cooling reduced the maximum module temperature to 46.1 °C and 52.3 °C, respectively. In addition, contacting the battery module with an aluminum mass without using an active cooling element reduced the temperature to 53.4 °C. The polyamide battery housing (holder) used in the module limited the cooling performance. Thus, simulations on alternative materials document how the cooling efficiency can be increased. © 2025 by the authors.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The transition to renewable energy sources from fossil fuels requires that the harvested energy be stored because of the intermittent nature of renewable sources. Thus, lithium-ion batteries have become a widely utilized power source in both daily life and industrial applications due to their high power output and long lifetime. In order to ensure the safe operation of these batteries at their desired power and capacities, it is crucial to implement a thermal management system (TMS) that effectively controls battery temperature. In this study, the thermal performance of a 1S14P lithium-ion battery module composed of cylindrical 18650 cells was compared for distinct cases of natural convection (no cooling), forced air convection, and phase change material (PCM) cooling. During the tests, the greatest temperatures were reached at a 2C discharge rate; the maximum module temperature reached was 55.4 °C under the natural convection condition, whereas forced air convection and PCM cooling reduced the maximum module temperature to 46.1 °C and 52.3 °C, respectively. In addition, contacting the battery module with an aluminum mass without using an active cooling element reduced the temperature to 53.4 °C. The polyamide battery housing (holder) used in the module limited the cooling performance. Thus, simulations on alternative materials document how the cooling efficiency can be increased. © 2025 by the authors. |
2024 |
Samancıoğlu, Umut Ege; Göçmen, Sinan; Madani, Seyed Saeed; Ziebert, Carlos; Nuno, Fernando; Huang, Jack; Gao, Frank; Çetkin, Erdal An experimental and comparative study on passive and active PCM cooling of a battery with/out copper mesh and investigation of PCM mixtures Journal Article 103 , 2024. @article{Samancıoğlu2024, title = {An experimental and comparative study on passive and active PCM cooling of a battery with/out copper mesh and investigation of PCM mixtures}, author = {Umut Ege Samancıoğlu and Sinan Göçmen and Seyed Saeed Madani and Carlos Ziebert and Fernando Nuno and Jack Huang and Frank Gao and Erdal Çetkin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85206987623&doi=10.1016%2fj.est.2024.114262&partnerID=40&md5=fdab2cfeba033f208b908b87d53c2bc1}, doi = {10.1016/j.est.2024.114262}, year = {2024}, date = {2024-01-01}, volume = {103}, abstract = {The carbon emission contribution to global warming accelerated both research on and transition to electric vehicles (EVs). Drivers demand high power, fast acceleration and less charging times. All these demands require high C rate charging/discharging demands from batteries. The rate of heat generation is exponentially proportional to C rates which decreases battery lifetime and may lead to thermal runaway. However, a battery thermal management system decreases thermal runaway risk and decelerates battery degradation via controlling battery temperature. In this paper, we first document the thermal conductivity enhancement via copper foam into phase change material (PCM) domain to uncover their possible use in EV thermal management applications. Maximum 15.93 times increment is achieved with a specific copper foam. Then, physical properties and behaviors of distinct PCM mixtures are documented. Homogeneity of mixtures is associated with the chemistry of PCMs and the mixture melting point is proportional to the volume weighted average of melting temperatures. The results document that the PCM with relatively lower melting point is beneficial when end of discharge temperatures considered, except for high discharge rate of 2C. Temperature uniformity across the battery increases with relatively higher melting point PCM. Experiments also document that the amount of PCM volume lost via insertion of copper foam yields higher end of discharge temperatures. Overall, both PCM and copper foam enhances temperature homogeneity and their benefit becomes more sensible during drive cycles relative to continuous charge/discharge use cases. © 2024 The Authors}, keywords = {}, pubstate = {published}, tppubtype = {article} } The carbon emission contribution to global warming accelerated both research on and transition to electric vehicles (EVs). Drivers demand high power, fast acceleration and less charging times. All these demands require high C rate charging/discharging demands from batteries. The rate of heat generation is exponentially proportional to C rates which decreases battery lifetime and may lead to thermal runaway. However, a battery thermal management system decreases thermal runaway risk and decelerates battery degradation via controlling battery temperature. In this paper, we first document the thermal conductivity enhancement via copper foam into phase change material (PCM) domain to uncover their possible use in EV thermal management applications. Maximum 15.93 times increment is achieved with a specific copper foam. Then, physical properties and behaviors of distinct PCM mixtures are documented. Homogeneity of mixtures is associated with the chemistry of PCMs and the mixture melting point is proportional to the volume weighted average of melting temperatures. The results document that the PCM with relatively lower melting point is beneficial when end of discharge temperatures considered, except for high discharge rate of 2C. Temperature uniformity across the battery increases with relatively higher melting point PCM. Experiments also document that the amount of PCM volume lost via insertion of copper foam yields higher end of discharge temperatures. Overall, both PCM and copper foam enhances temperature homogeneity and their benefit becomes more sensible during drive cycles relative to continuous charge/discharge use cases. © 2024 The Authors |
Samancoğlu, Umut Ege; Koşar, Ali; Cetkin, Erdal Optimization of Y-Shaped Micro-Mixers With a Mixing Chamber for Increased Mixing Efficiency and Decreased Pressure Drop Journal Article 146 (4), 2024. @article{Samancoğlu2024, title = {Optimization of Y-Shaped Micro-Mixers With a Mixing Chamber for Increased Mixing Efficiency and Decreased Pressure Drop}, author = {Umut Ege Samancoğlu and Ali Koşar and Erdal Cetkin}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85185843804&doi=10.1115%2f1.4064443&partnerID=40&md5=329f6f13e703302e62731d685c727b4e}, doi = {10.1115/1.4064443}, year = {2024}, date = {2024-01-01}, volume = {146}, number = {4}, abstract = {In this study, Y-shaped micromixers with mixing chamber design optimized as rotation and chaotic advection in the fluid domain increase with the chamber. Motivated by the advantages of Y-shaped mixers, a parametric study was performed for inlet angles (a, b), inlet channel eccentricities (x-ecc, z-ecc) and length scale ratios (L1/L2, D1/D2, and Vsp). z-eccentricity is introduced in addition to x-eccentricity to create a design that further enhances the swirl and chaotic advection inside mixing chamber for the first time. The results reveal that the maximum mixing efficiency can be achieved for Reynolds number of 81 and a, b, x-ecc, z-ecc, D1/D2, and L1/L2 values of 210◦, 60◦, 20 lm, 20 lm, 1.8, and 4, respectively. In addition, the proposed Y-shaped micromixer leads to a lower pressure drop (at least 50% reduction for all Reynolds numbers) in comparison to competing design. The maximum reduction in pressure drop is 72% less than the curved-straight-curved (CSC) (Re ¼ 81) with mixing efficiency of 88% and pressure drop of 9244.4 Pa. Overall, an outstanding mixing efficiency was offered over a wide range of Reynolds numbers with distinctly low pressure drop and a compact micromixer design, which could be beneficial for a wide variety of applications where volume and pumping power are limited. Copyright © 2024 by ASME.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this study, Y-shaped micromixers with mixing chamber design optimized as rotation and chaotic advection in the fluid domain increase with the chamber. Motivated by the advantages of Y-shaped mixers, a parametric study was performed for inlet angles (a, b), inlet channel eccentricities (x-ecc, z-ecc) and length scale ratios (L1/L2, D1/D2, and Vsp). z-eccentricity is introduced in addition to x-eccentricity to create a design that further enhances the swirl and chaotic advection inside mixing chamber for the first time. The results reveal that the maximum mixing efficiency can be achieved for Reynolds number of 81 and a, b, x-ecc, z-ecc, D1/D2, and L1/L2 values of 210◦, 60◦, 20 lm, 20 lm, 1.8, and 4, respectively. In addition, the proposed Y-shaped micromixer leads to a lower pressure drop (at least 50% reduction for all Reynolds numbers) in comparison to competing design. The maximum reduction in pressure drop is 72% less than the curved-straight-curved (CSC) (Re ¼ 81) with mixing efficiency of 88% and pressure drop of 9244.4 Pa. Overall, an outstanding mixing efficiency was offered over a wide range of Reynolds numbers with distinctly low pressure drop and a compact micromixer design, which could be beneficial for a wide variety of applications where volume and pumping power are limited. Copyright © 2024 by ASME. |
Res. Assist. Mehmet Yalçın Sırmalılar

Educational Background
B.Sc. Manisa Celal Bayar University, Mechanical Engineering, 2021
M.Sc. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Finite Element Analiysis
- Biomechanics
- Optimization of Medical Implants
- Strength of Materials
- +90 232 750 6718
- +90 232 750 6701
- Mechanical Engineering Building, Research Assistants Office (Z46)
Res. Assist. Senagül Tunca Taşkıran

Educational Background
B.Sc. Dokuz Eylül University, Metallurgical and Materials Engineering, 2019
M.Sc. İzmir Institute of Technology, Mechanical Engineering, 2023
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Composite Materials
- Mechanical Behaviour of Materials
- Materials Characterization
- +90 232 750 6757
- +90 232 750 6701
- Mechanical Engineering Building, Robotic Manufacturing Systems Lab. (RoManS) (Z57)
2024 |
Taşkıran, Senagül Tunca; Tanoğlu, Metin; Çerci, Nazife; Cevahir, Aref; Damar, Ceren Türkdoğan; Ünver, Elçin; Aktaş, Mustafa İlker Development of resin-based dental composites containing hydroxyapatite and zirconia nanoparticles Journal Article 45 (11), pp. 10470 – 10485, 2024. @article{TuncaTaşkıran202410470, title = {Development of resin-based dental composites containing hydroxyapatite and zirconia nanoparticles}, author = {Senagül Tunca Taşkıran and Metin Tanoğlu and Nazife Çerci and Aref Cevahir and Ceren Türkdoğan Damar and Elçin Ünver and Mustafa İlker Aktaş}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85192195777&doi=10.1002%2fpc.28488&partnerID=40&md5=e1bddd711ce08dadf4e46669d071d6ae}, doi = {10.1002/pc.28488}, year = {2024}, date = {2024-01-01}, volume = {45}, number = {11}, pages = {10470 – 10485}, abstract = {In clinical applications, resin-based dental composites primarily face challenges with fractures and secondary caries. To overcome these issues, the physical characteristics of dental composites, especially mechanical properties, need to be improved. Hydroxyapatite (HA), present in the structure of the teeth, is preferred due to its biological properties, and zirconia (ZrO2) nanoparticles are known to enhance the mechanical properties of this type of composites. The aim of this study is to develop resin-based dental composites containing HA and ZrO2 nanoparticles. The study also aims to explore the synergistic effect of these two nanoparticles on the physical properties of the developed composites. Composites with nine different compositions were prepared by mixing the components with the help of a mortar mill. The flexural and compressive strength, polymerization shrinkage, depth of cure and water sorption, and solubility properties of the prepared composites have been investigated. All composites have been found to meet the requirements of ISO 4049 standard. Among them, composite containing 5 wt. % HA and 1 wt. % ZrO2 (H5Z1) has exhibited the highest flexural strength with an increase of 58% compared to the control sample, and composite containing 3 wt. % HA and 2 wt. % ZrO2 (H3Z2) has exhibited the highest compressive strength with an increase of 22% compared to the control sample. Other physical properties of the composites have been found to be in an acceptable level. Highlights: Dental composites with HA and ZrO2 fillers were developed by a mortar mill. Synergistic effect of HA and ZrO2 nanoparticles was investigated. Mechanical properties of dental composites were significantly improved. Physical properties of dental composites were found to be at acceptable levels. Depth of cure decreases with increasing HA and ZrO2 loading. © 2024 The Authors. Polymer Composites published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In clinical applications, resin-based dental composites primarily face challenges with fractures and secondary caries. To overcome these issues, the physical characteristics of dental composites, especially mechanical properties, need to be improved. Hydroxyapatite (HA), present in the structure of the teeth, is preferred due to its biological properties, and zirconia (ZrO2) nanoparticles are known to enhance the mechanical properties of this type of composites. The aim of this study is to develop resin-based dental composites containing HA and ZrO2 nanoparticles. The study also aims to explore the synergistic effect of these two nanoparticles on the physical properties of the developed composites. Composites with nine different compositions were prepared by mixing the components with the help of a mortar mill. The flexural and compressive strength, polymerization shrinkage, depth of cure and water sorption, and solubility properties of the prepared composites have been investigated. All composites have been found to meet the requirements of ISO 4049 standard. Among them, composite containing 5 wt. % HA and 1 wt. % ZrO2 (H5Z1) has exhibited the highest flexural strength with an increase of 58% compared to the control sample, and composite containing 3 wt. % HA and 2 wt. % ZrO2 (H3Z2) has exhibited the highest compressive strength with an increase of 22% compared to the control sample. Other physical properties of the composites have been found to be in an acceptable level. Highlights: Dental composites with HA and ZrO2 fillers were developed by a mortar mill. Synergistic effect of HA and ZrO2 nanoparticles was investigated. Mechanical properties of dental composites were significantly improved. Physical properties of dental composites were found to be at acceptable levels. Depth of cure decreases with increasing HA and ZrO2 loading. © 2024 The Authors. Polymer Composites published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers. |
Res. Assist. Büşra İrem Türkpençesi

Educational Background
B.Sc. İzmir Institute of Technology, Chemical Engineering, 2021 / Minor Program Mechanical Engineering, 2020
M.Sc. İzmir Institute of Technology, Mechanical Engineering, 2025
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Metallic Biomaterials
- Additive Manufacturing of Metallic Materials
- Materials Characterization
- +90 232 750 6749
- +90 232 750 6701
- Mechanical Engineering Building, Advanced Materials and Manufacturing Lab. (149)
Res. Assist. Samedhan Yıldırım

Educational Background
B.Sc. Izmir Institute of Technology, Mechanical Engineering, 2020
M.Sc. Izmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Static and Dynamic Mechanical Behaviour of Materials
- Materials Characterization
- Numerical Modelling of Materials
- +90 232 750 6624
- +90 232 750 6701
- Dynamic Test and Modelling Laboratory
Res. Assist. F. Murat Yıldıztekin

Educational Background
B.Sc. Dokuz Eylül University, Mechanical Engineering, 2019
Ph.D. Izmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Ballistic Fracture Mechanics
- High Strain Rate Deformation Behaviour of Materials
- Ceramic Armors
- Numerical Modelling of Materials
- +90 232 750 6624
- +90 232 750 6701
- Dynamic Test and Modelling Laboratory
2025 |
Erten, H İ; Çimen, G; Yıldıztekin, F M; Güden, M Analysis and Comparison of the Projectile Impact Response of an Electron Beam Melt-Ti64 Body Centered Cubic Lattice-Cored Sandwich Plate Journal Article 2025. @article{Erten2025, title = {Analysis and Comparison of the Projectile Impact Response of an Electron Beam Melt-Ti64 Body Centered Cubic Lattice-Cored Sandwich Plate}, author = {H İ Erten and G Çimen and F M Yıldıztekin and M Güden}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85217163382&doi=10.1007%2fs11340-025-01150-9&partnerID=40&md5=85bf408e4746b784c64e57acb0edd288}, doi = {10.1007/s11340-025-01150-9}, year = {2025}, date = {2025-01-01}, abstract = {Background: One potential application of additively fabricated lattice structures is in the blade containment rings of gas turbine engines. The blade containment rings are expected to be able to absorb the kinetic energy of a released blade (broken blade) in order to protect the engine parts from damaging. Metallic lattice-cored sandwich plates provide a gap (free space) between two face sheets, which helps to arrest the released blade and increases the energy absorption capability of containment rings. Objective: The objective was to investigate numerically the projectile impact response of Body-Centered-Cubic (BCC) Electron-Beam-Melt (EBM) lattice-cored/Ti64 face sheet sandwich plates as compared with that of an equal-mass monolithic EBM-Ti64 plate. Methods: The projectile impact simulations were implemented in LS-DYNA using the previously determined flow stress and damage models and a spherical steel impactor at the velocities ranging from 150 to 500 m s−1. The experimental projectile impact tests on the monolithic plate were performed at two different impact velocities and the results were used to confirm the validity of the used flow stress and damage models for the monolithic plate models. Results: Lower impact stresses were found numerically in the sandwich plate as compared with the monolithic plate at the same impact velocity. The bending and multi-cracking of the struts over a wide area in the sandwich plate increased the energy absorption and resulted in the arrest of the projectile at relatively high velocities. While monolithic plate exhibited a local bent area, resulting in the development of high tensile stresses and the projectile perforations at lower velocities. Conclusions: The numerical impact stresses in the sandwich plate were distributed over a wider area around the projectile, leading to the fracture and bending of many individual struts which significantly increased the resistance to the perforation. Hence, the investigated lattice cell topology and cell, strut, and face sheet sizes and the lattice-cored sandwich plate was shown potentially more successful in stopping the projectiles than the equal-mass monolithic plates. © The Author(s) 2025.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Background: One potential application of additively fabricated lattice structures is in the blade containment rings of gas turbine engines. The blade containment rings are expected to be able to absorb the kinetic energy of a released blade (broken blade) in order to protect the engine parts from damaging. Metallic lattice-cored sandwich plates provide a gap (free space) between two face sheets, which helps to arrest the released blade and increases the energy absorption capability of containment rings. Objective: The objective was to investigate numerically the projectile impact response of Body-Centered-Cubic (BCC) Electron-Beam-Melt (EBM) lattice-cored/Ti64 face sheet sandwich plates as compared with that of an equal-mass monolithic EBM-Ti64 plate. Methods: The projectile impact simulations were implemented in LS-DYNA using the previously determined flow stress and damage models and a spherical steel impactor at the velocities ranging from 150 to 500 m s−1. The experimental projectile impact tests on the monolithic plate were performed at two different impact velocities and the results were used to confirm the validity of the used flow stress and damage models for the monolithic plate models. Results: Lower impact stresses were found numerically in the sandwich plate as compared with the monolithic plate at the same impact velocity. The bending and multi-cracking of the struts over a wide area in the sandwich plate increased the energy absorption and resulted in the arrest of the projectile at relatively high velocities. While monolithic plate exhibited a local bent area, resulting in the development of high tensile stresses and the projectile perforations at lower velocities. Conclusions: The numerical impact stresses in the sandwich plate were distributed over a wider area around the projectile, leading to the fracture and bending of many individual struts which significantly increased the resistance to the perforation. Hence, the investigated lattice cell topology and cell, strut, and face sheet sizes and the lattice-cored sandwich plate was shown potentially more successful in stopping the projectiles than the equal-mass monolithic plates. © The Author(s) 2025. |
2023 |
Güden, Mustafa; Riaz, Arslan Bin; Toksoy, Ahmet Kaan; Yıldıztekin, Murat; Erten, Hacer İrem; Çimen, Gülden; Hızlı, Burak; Çellek, Burçin Seven; Güleç, Efe; Taşdemirci, Alper; Yavaş, Hakan; Altınok, Sertaç Materials Science and Engineering: A, 885 , 2023. @article{Güden2023b, title = {Investigation and validation of the flow stress equation and damage model parameters of an electron beam melted Ti6Al4V alloy with a martensitic phase}, author = {Mustafa Güden and Arslan Bin Riaz and Ahmet Kaan Toksoy and Murat Yıldıztekin and Hacer İrem Erten and Gülden Çimen and Burak Hızlı and Burçin Seven Çellek and Efe Güleç and Alper Taşdemirci and Hakan Yavaş and Sertaç Altınok}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85171624739&doi=10.1016%2fj.msea.2023.145590&partnerID=40&md5=206e908384653029d335d5611a983306}, doi = {10.1016/j.msea.2023.145590}, year = {2023}, date = {2023-01-01}, journal = {Materials Science and Engineering: A}, volume = {885}, abstract = {The Johnson and Cook flow stress and damage model parameters of an electron beam melt (EBM)-Ti64 alloy composed of α' (martensite) and α+β and an extruded-annealed conventional Ti64 alloy were determined experimentally. The validities of the determined flow stress equations and damage model parameters were then verified by the numerical simulations of the compression tests on the Body Centered Cubic lattices produced using the same EBM parameters with the solid EBM samples. In addition, a compression flow stress equation was extracted from the small-size test specimens (1 and 2 mm diameter) taken directly from the struts of the as-built lattices. The microscopic observations, XRD analyses and hardness tests confirmed the presence of α′ phase in the EBM solid samples and in the struts of the BCC lattices, which reduced the ductility of the EBM solid specimens and struts compared to the conventional Ti64. Furthermore, the partially melt particles on the surfaces of the struts acted as the stress concentration sides for micro-cracking; hence, the compression flow stresses of the struts were found to be significantly lower than those of the as-built EBM solid specimens. The flow stress equation derived from the struts predicted more accurately the compression behavior of the lattices. The compression tests and models showed that early damage formation in the lattices was noted to decrease the initial peak and post-peak stresses. As with the experiments, the initial damage occurred in the models with the separation of the nodes at the lattice cell surface edges. This resulted in an abrupt reduction in the stresses after the peak stress. The numerical lattices without damage showed a localized lattice deformation at the mid-sections and the stress increased continuously as a function of normal strain. © 2023 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Johnson and Cook flow stress and damage model parameters of an electron beam melt (EBM)-Ti64 alloy composed of α' (martensite) and α+β and an extruded-annealed conventional Ti64 alloy were determined experimentally. The validities of the determined flow stress equations and damage model parameters were then verified by the numerical simulations of the compression tests on the Body Centered Cubic lattices produced using the same EBM parameters with the solid EBM samples. In addition, a compression flow stress equation was extracted from the small-size test specimens (1 and 2 mm diameter) taken directly from the struts of the as-built lattices. The microscopic observations, XRD analyses and hardness tests confirmed the presence of α′ phase in the EBM solid samples and in the struts of the BCC lattices, which reduced the ductility of the EBM solid specimens and struts compared to the conventional Ti64. Furthermore, the partially melt particles on the surfaces of the struts acted as the stress concentration sides for micro-cracking; hence, the compression flow stresses of the struts were found to be significantly lower than those of the as-built EBM solid specimens. The flow stress equation derived from the struts predicted more accurately the compression behavior of the lattices. The compression tests and models showed that early damage formation in the lattices was noted to decrease the initial peak and post-peak stresses. As with the experiments, the initial damage occurred in the models with the separation of the nodes at the lattice cell surface edges. This resulted in an abrupt reduction in the stresses after the peak stress. The numerical lattices without damage showed a localized lattice deformation at the mid-sections and the stress increased continuously as a function of normal strain. © 2023 Elsevier B.V. |
Res. Assist. Tuğrul Yılmaz

Educational Background
B.Sc. İzmir Institute of Technology, Mechanical Engineering, 2020
M.Sc. İzmir Institute of Technology, Mechanical Engineering, 2023
Ph.D. İzmir Institute of Technology, Mechanical Engineering, (Ongoing)
Research Interests
- Mechanisms
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- Mechanical Engineering Building, Fluid Mechanics Lab. (Z64)