Browsing by Author "Kalay, Onur Can"
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Publication A comparative 3d finite element computational study of stress distribution and stress transfer in small-diameter conical dental implants(Univ Osijek, Tech Fac, 2021-12-01) Doğan, Oğuz; Dhanasekaran, Lokesh; Khandaker, Morshed; Kalay, Onur Can; Karaman, Hasan; Karpat, Fatih; KARPAT, FATİH; Doğan, Oguz; DOĞAN, OĞUZ; Yuce, Celalettin; YÜCE, CELALETTİN; Karpat, Esin; KARPAT, ESİN; Dhanasekaran, Lokesh; Khandaker, Morshed; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi.; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Elektrik Elektronik Mühendisliği.; 0000-0001-8643-6910; 0000-0001-8474-7328; 0000-0003-1387-907X; 0000-0001-5985-7402; A-5259-2018; GXH-1702-2022; AAV-7897-2020; R-3733-2017The implant design is one of the main factors in implant stability because it affects the contact area between the bone and the implant surface and the stressstrain distribution at the bone-implant interface. In this study, the effect of different groove geometries on stress-strain distributions in small-diameter conical implants is investigated using the finite element method (FEM). Four different thread models (rectangular, buttressed, reverse buttressed, and symmetrical profile) are created by changing the groove geometry on the one-piece implants, and the obtained results are compared. The stress shielding effect is investigated through the dimensionless numbers that characterize the load-sharing between the bone-implant. It is determined that the lowest stress distribution is observed with rectangular profiled groove geometry. Besides, it is obtained that the buttressed groove geometry minimizes the stress effects transmitted to the periphery of the implant. The symmetrical profiles had better performance than rectangular profiles in stress transfer.Publication A comparative experimental study on the impact strength of standard and asymmetric involute spur gears(Elsevier, 2021-01-06) Kalay, Onur Can; Doğan, Oğuz; Yılmaz, Tufan Gürkan; Yüce, Celalettin; Karpat, Fatih; Kalay, Onur Can; YILMAZ, TUFAN GÜRKAN; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0003-3772-7871; 0000-0001-8474-7328; GDQ-4936-2022; V-6153-2017; A-5259-2018Gears are one of the main components of the power transmission systems and are used in various fields. Problems caused by sudden load changes in mobile systems are frequently encountered today. Gear dynamics have become more influential due to demands of high power transmission capability, long life, and low-cost. However, inertial forces caused by accelerated movements of gear can have unpredictable results. The impact loads must be calculated correctly. It is inconvenient to determine the impact strength of gear via standard drop-weight test rig due to inhomogeneity and complex geometries. This study investigates how the tooth profile affects the impact load on the involute spur gears. For this reason, a special test setup and experimental approach was proposed to examine the influence of the asymmetric profile on the impact strength. It was observed that the peak force values increased by approximately 15.3% when using 20/30 degrees asymmetric profile gears in comparison with the 20 degrees/20 degrees standard design. This improvement can reach up to 25.8% in terms of peak force energy. The results indicate that the proposed novel test setup and the experimental method can be used for measuring the impact strength of asymmetric involute gears.Publication A one-dimensional convolutional neural network-based method for diagnosis of tooth root cracks in asymmetric spur gear pairs(Mdpi, 2023-04-01) Kalay, Onur Can; KALAY, ENGİN; Karpat, Esin; DİRİK, AHMET EMİR; Dirik, Ahmet Emir; Karpat, Fatih; 0000-0001-8643-6910; 0000-0001-8474-7328; KIK-4851-2024; A-5259-2018Gears are fundamental components used to transmit power and motion in modern industry. Their health condition monitoring is crucial to ensure reliable operations, prevent unscheduled shutdowns, and minimize human casualties. From this standpoint, the present study proposed a one-dimensional convolutional neural network (1-D CNN) model to diagnose tooth root cracks for standard and asymmetric involute spur gears. A 6-degrees-of-freedom dynamic model of a one-stage spur gear transmission was established to achieve this end and simulate vibration responses of healthy and cracked (25%-50%-75%-100%) standard (20 degrees/20 degrees) and asymmetric (20 degrees/25 degrees and 20 degrees/30 degrees) spur gear pairs. Three levels of signal-to-noise ratios were added to the vibration data to complicate the early fault diagnosis task. The primary consideration of the present study is to investigate the asymmetric gears' dynamic characteristics and whether tooth asymmetry would yield an advantage in detecting tooth cracks easier to add to the improvements it affords in terms of impact resistance, bending strength, and fatigue life. The findings indicated that the developed 1-D CNN model's classification accuracy could be improved by up to 12.8% by using an asymmetric (20 degrees/30 degrees) tooth profile instead of a standard (20 degrees/20 degrees) design.Publication An investigation on the design of formate and generate face milled hypoid gears(Amer Soc Mechanical Engineers, 2020-01-01) Doğanlı, Mert; Altıntaş, Elif; Yılmaz, Tufan Gürkan; YILMAZ, TUFAN GÜRKAN; Kalay, Onur Can; Karpat, Fatih; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0003-3772-7871; 0000-0001-8643-6910; 0000-0001-8474-7328; A-5259-2018Hypoid gears are transmission elements that transfer power and moment between shafts whose axes do not intersect. They are similar in structure to spiral bevel gears. However, there are many advantages compared to spiral bevel gears in terms of load carrying capacity and rigidity. Hypoid gear pairs are mostly used as powertrain on the rear axles of cars and trucks. Hypoid gears are manufactured by two essential methods called face-milling and face-hobbing, and there are mainly two relative kinematic movements (Formate (R) and Generate). In this study, the gears produced with the Face-milling method are discussed. Face milled hypoid gears can be manufactured with both Formate (R) and Generate, while pinions can only be manufactured with the Generate method. The most crucial factor that determines the performance of hypoid gears is the geometry of hypoid gears. The gear and pinion geometry is directly dependent on the tool geometry, machine parameters, and relative motion between the cradle and the workpiece. The gear geometry determines the contact shape and pressure during power transmission. In this study, the mathematical equation of the cutting tool is set. After that, using differential geometry, coordinate transformation, and the gearing theory, the mathematical equation of hypoid gear is obtained.Item Effects of crack initialization angle on crack propagation path of thin rim gears for wind turbines(Bursa Uludağ Üniversitesi, 2020-03-29) Doğan, Oğuz; Kalay, Onur Can; Karpat, Fatih; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0003-4203-8237; 0000-0001-8643-6910; 0000-0001-8474-7328Nowadays, wind turbines are one of the main subjects of the designers due to the everincreasing interest in renewable energy sources. Due to dynamic loads that effect the gear system, cracks may observe on the gear teeth. These cracks may proceed along either the tooth or the rim. In similar cases, if the crack proceeds along with the tooth, crack classified as benign. If the crack proceeds along with the rim direction, the cracks can be classified as catastrophic cracks. In this study, the effects of crack initialization angle and backup ratio on the crack propagation path are investigated numerically for spur gears. The maximum stress location at the gear root is defined as the crack starting point. The initial cracks are opened with 0° - 45° - and 90° crack initialization angles. Also, five different backup ratios are used for crack propagation analysis. The analyses are performed in ANSYS Workbench, SMART Crack Growth module. The crack propagation paths are evaluated for fifteen analyses. As a result, if the rim thickness is high, the crack initialization angle has no effects on the crack paths. It has an influence on the crack propagation paths for the special rim thickness.Publication Effects of tooth root cracks on vibration and dynamic transmission error responses of asymmetric gears: A comparative study(Taylor & Francis Inc, 2023-03-03) Doğan, Oğuz; YÜCE, CELALETTİN; Kalay, Onur Can; Yüce, Celalettin; Karpat, Fatih; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makina Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0003-4203-8237; 0000-0003-1387-907X; 0000-0001-8474-7328; R-3733-2017; AAV-7897-2020; A-5259-2018Gears are significant machine elements used in various industrial applications. An undetected fault in a gear transmission system may lead to a fatal breakdown and, thus, severe economic losses or even human casualties. From this standpoint, the present study developed a numerical method to detect root crack damages in symmetric and asymmetric involute spur gears. To achieve this end, the single tooth stiffness values were calculated for healthy and cracked (25%-50%-75%-100%) gears, and then the time-varying mesh stiffness was obtained. A six-degree-of-freedom dynamic model of a single-stage gear mechanism was developed to collect vibration and Dynamic Transmission Error (DTE) signals. The efficacy of vibration and DTE responses in fault detection was compared through six statistical indicators. The results indicate that the vibration signals were more effective than DTE in detecting tooth root cracks. It was observed that the statistical indicator changes significantly increase with the increment of the drive side pressure angle from 20 degrees to 30 degrees for the backup ratios where the root crack propagates along the tooth, thus making fault detection easier. The findings could provide significant outputs for a better understanding of the influence of tooth asymmetry on gear dynamics characteristics and early fault diagnosis.Publication Experimental investigation of the impact resistance of involute spur gears(IEEE, 2018-01-01) Doğan, Oğuz; Yüce, Celalettin; Karpat, Fatih; Kalay, Onur Can; IEEE; DOĞAN, OĞUZ; YÜCE, CELALETTİN; KARPAT, FATİH; Kalay, Onur Can; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi; 0000-0003-4203-8237; 0000-0003-1387-907X; 0000-0001-8474-7328; 0000-0001-8643-6910; A-5259-2018; GXH-1702-2022; R-3733-2017; GDQ-4936-2022Gears are the most commonly used power transmission element in today's world. Due to their advantages, gears are widely used in many sectors such as aerospace, space, wind turbines, automotive, etc. In these sectors the moment, speed and power values that need to be transmitted are increasing day by day. Due to the increased power and moment values, gears are exposed to high dynamic, impact loads and they are subject to damage due to these loads. For this reason, the impact resistance of the gears must be determined carefully in the design phase of the gear. In this study, an experimental method for determining impact loads of the gears is developed. A special drop gear impact test setup is designed and manufactured to determine the impact loads on the gear. The test setup works by dropping the load on the gear tooth from a certain height. In this way, the teeth are broken and the impact load, acceleration and displacement values are measured by using special measurement instruments which are attached on the test setup. The effect of surface hardness on impact loads is investigated. Two different gear samples are used in the experiments. It is seen that the surface hardness has great effect on the impact loads of the gears. It has been found that surface hardened gears have much higher impact strength than unhardened gears.Publication Fatigue performances of helicopter gears(Walter De Gruyter Gmbh, 2023-01-27) Doğan, Oğuz; Yılmaz, Tufan Gürkan; YÜCE, CELALETTİN; Kalay, Onur Can; Karpat, Esin; Kopmaz, Osman; KOPMAZ, OSMAN; Karpat, Fatih; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Elektrik ve Elektronik Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0003-1387-907X; 0000-0003-4203-8237; 0000-0003-3772-7871; 0000-0001-8474-7328; A-5259-2018; V-6153-2017; R-3733-2017Gears are widely used machine elements to transmit power and motion in the industry. During the power transmission, the gears are subjected to cyclic loads. Thus the fatigue resistance of the gears should be deeply investigated. In particular, this issue is gaining much more importance in the space and aviation fields. In this study, the fatigue life of gears made of 9310-VIM-VAR steel used in the aviation field was determined experimentally, and the crack propagation paths obtained were numerically verified. To this end, the SAE J1619 standard single-tooth bending fatigue test apparatus was redesigned and manufactured in order to adapt it to the helicopter gears. Totally 28 single-tooth bending fatigue tests were carried out for various loading conditions. Accordingly, the S-N curves for the helicopter gears were created. The experimental results were verified by the finite element fatigue crack propagation analysis in terms of the initial crack location, crack initialization angle, and crack propagation paths. Conducted experiments and numerical studies are found as compatible with each other.Publication Fault diagnosis with deep learning for standard and asymmetric involute spur gears(Amer Soc Mechanical Engineers, 2021-01-01) Yuce, Celalettin; Dogan, Oguz; Karpat, Fatih; Dirik, Ahmet Emir; KARPAT, FATİH; DİRİK, AHMET EMİR; Kalay, Onur Can; Korcuklu, Burak; KORCUKLU, BURAK; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi; 0000-0001-8474-7328; 0000-0002-6200-1717; 0000-0001-8643-6910; 0000-0003-1387-907X; A-5259-2018; R-3733-2017Gears are critical power transmission elements used in various industries. However, varying working speeds and sudden load changes may cause root cracks, pitting, or missing tooth failures. The asymmetric tooth profile offers higher load-carrying capacity, long life, and the ability to lessen vibration than the standard (symmefric) profile spur gears. Gearbox faults that cannot be detected early may lead the entire system to stop or serious damage to the machine. In this regard, Deep Learning (DL) algorithms have started to be utilized for gear early fault diagnosis. This study aims to determine the root crack for both symmefric and asymmefric involute spur gears with a DL-based approach. To this end, single tooth stiffness of the gears was obtained with ANSYS software for healthy and cracked gears (50-100%), and then the time-varying mesh stiffness (TVMS) was calculated. A six-degrees-of-freedom dynamic model was developed by deriving the equations of motion of a single-stage spur gear mechanism. The vibration responses were collected for the healthy state, 50% and 100% crack degrees for both symmefric and asymmefric tooth profiles. Furthermore, the white Gaussian noise was added to the vibration data to complicate the early crack diagnosis task. The main contribution of this paper is that it adapts the DL-based approaches used for early fault diagnosis in standard profile involute spur gears to the asymmefric tooth concept for the first time. The proposed method can eliminate the need for large amounts of training data from costly physical experiments. Therefore, maintenance strategies can be improved by early crack detection.Item Influence of linear profile modifications on the dynamic loading of a spur gear(Bursa Uludağ Üniversitesi, 2021-05-21) Doğan, Oğuz; Kalay, Onur Can; Karpat, Fatih; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0001-8474-7328Gear dynamics is one of the most critical subjects in gear design because of its remarkable effect on vibration levels, load-carrying capacity, and noise. The tip relief modification is known as a simple method to decrease dynamic loads in the industry. The primary goal of this study is to understand the influence of tip relief modification on the dynamic performance of the spurs gears. In this paper, the meshing process and gear mesh stiffness calculation method are defined. A dynamic model with two- degree-of-freedom is created to find the dynamic response of the spur gear pair. The simulations are carried out with standard and different tip modified spur gear pairs. It is observed that the tip relief modification has an excellent effect on the gear dynamic response. However, this effect is restricted until a certain amount of tip relief modification. After the optimum amount of tip relief modification, the dynamic loads are increased considerably. Thus, a computer program is developed to find the optimum amount of tip relief modification in MATLAB® for the gear designers. The program outputs are given for two different case studies. As a result of the study, the dynamic factor behaves like a “V form” according to the tip relief modification, and the dynamic force decreased approximately 25% for optimum profile modification.Publication Influence of tooth root cracks on the mesh stiffness of asymmetric spur gear pair with different backup ratios(Sage Publications Ltd, 2022-09-16) Doğan, Oğuz; Kalay, Onur Can; Karpat, Fatih; Kalay, Onur Can; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0001-8474-7328; A-5259-2018; GXH-1702-2022Gears are critical machine elements that transmit power and motion in diverse implementation fields. Over time, gears may produce a series of faults due to harsh operating conditions, fatigue, manufacturing errors, etc., leading to severe performance degradation. During the meshing process, the stiffness of a single tooth controls the load sharing, vibration, and noise characteristics of a geared system. An undetected fault could decrease the gear stiffness and thus may lead to a fatal breakdown, substantial economic losses, or even human casualties in safety-critical applications such as helicopters, high-speed trains, and wind turbines. Hence, the accurate quantification of the gear stiffness emerges as an important research area to obtain reliable gear designs. With this in mind, the asymmetric tooth concept offers superior bending strength, fatigue propagation life, and the ability to lessen vibration over the standard (symmetric) designs in applications where unidirectional loadings are predominant. This study investigates the influence of tooth root cracks on the single-tooth and meshing stiffness characteristics of the standard and asymmetric involute spur gears. To this end, the numerical crack propagation paths obtained in our previous works were introduced to the created 3D CAD geometries. Subsequently, the single tooth stiffness of both healthy and cracked (2 5%-50%-75%100%) gears was calculated through the ANSYS (R) Workbench, and the time-varying mesh stiffness was obtained. The present study evaluated the effects of backup ratio and the tooth asymmetry on the spur gears' meshing stiffness characteristics simultaneously and further expanded the scope of the research work. The results indicated that the single tooth stiffness and mesh stiffness could be improved by 35% and 22%, respectively, as the drive side pressure angle increased from 20 degrees to 35 degrees. It has been noted that the gear stiffness decreased as the crack level increased, while the increment of the backup ratio further increased the reduction in the stiffness. The findings could provide significant outputs for a better understanding of the influence of tooth asymmetry on the gear dynamics characteristics, life prediction, and early fault diagnosis.Publication Investigation of infectious droplet dispersion in a hospital examination room cooled by split-type air conditioner(Springer, 2024-05-08) Yüce, Bahadir Erman; Kalay, Onur Can; Karpat, Fatih; Alemdar, Adem; Temel, Şehime Gülsün; Dilektaşlı, Aslı Görek; Başkan, Emel Bülbül; Özakın, Cüneyt; Coşkun, Burhan; YÜCE, BAHADIR ERMAN; Kalay, Onur Can; KARPAT, FATİH; ALEMDAR, ADEM; TEMEL, ŞEHİME GÜLSÜN; GÖREK DİLEKTAŞLI, ASLI; BÜLBÜL BAŞKAN, EMEL; ÖZAKIN, CÜNEYT; COŞKUN, BURHAN; Bursa Uludağ Üniversitesi/Yenişehir İbrahim Orhan Meslek Yüksekokulu/İklimlendirme ve Soğutma Teknolojisi Bölümü.; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Sağlık Bilimleri Enstitüsü.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Tıbbi Genetik Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Histoloji ve Embriyoloji Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Göğüs Hastalıkları Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Dermatoloji Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Enfeksiyon Hastalıkları ve Mikrobiyoloji Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Üroloji Anabilim Dalı.The novel coronavirus (SARS-CoV-2) outbreak has spread worldwide, and the World Health Organization (WHO) declared a global pandemic in March 2020. The transmission mechanism of SARS-CoV-2 in indoor environments has begun to be investigated in all aspects. In this regard, many numerical studies on social distancing and the protection of surgical masks against infection risk have neglected the evaporation of the particles. Meanwhile, a 1.83 m (6 feet) social distancing rule has been recommended to reduce the infection risk. However, it should be noted that most of the studies were conducted in static air conditions. Air movement in indoor environments is chaotic, and it is not easy to track all droplets in a ventilated room experimentally. Computational Fluid Dynamics (CFD) enables the tracking of all particles in a ventilated environment. This study numerically investigated the airborne transmission of infectious droplets in a hospital examination room cooled by a split-type air conditioner with the CFD method. Different inlet velocities (1, 2, 3 m/s) were considered and investigated separately. Besides, the hospital examination room is a model of one of the Bursa Uludag University Hospital examination rooms. The patient, doctor, and some furniture are modeled in the room. Particle diameters considered ranged from 2 to 2000 mu m. The evaporation of the droplets is not neglected, and the predictions of particle tracks are shown. As a result, locations with a high infection risk were identified, and the findings that could guide the design/redesign of the hospital examination rooms were evaluated.Publication Laser-induced microgrooves improve the mechanical responses of cemented implant systems(MDPI, 2020-04-27) Khandaker, Morshed; Moussa, Abdellah Ait; Sama, Desmond Nuyebga; Safavinia, Fereshteh; Hazra, Susmita; Kalay, Onur Can; Karpat, Fatih; Clary, Erik; Haleem, Amgad; Kalay, Onur Can; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-8643-6910; 0000-0001-8474-7328; GDQ-4936-2022 ; A-5259-2018The impact of a laser-induced microgroove (LIM) architecture on mechanical responses of two cemented implant systems was evaluated. One system consisted of two aluminum alloy rods bonded end-to-end by polymethylmethacrylate cement. The second system consisted of a custom-made, aluminum tibial tray (TT) cemented in an artificial canine tibia. Control specimens for each system were polished smooth at the cement interface. For LIM samples in the rod system, microgrooves were engraved (100 mu m depth, 200 mu m width, 500 mu m spacing) on the apposing surface of one of the two rods. For TT system testing, LIM engraving (100 mu m spacing) was confined to the underside and keel of the tray. Morphological analysis of processed implant surfaces revealed success in laser microgrooving procedures. For cemented rods tested under static tension, load to failure was greater for LIM samples (279.0 +/- 14.9 N vs. 126.5 +/- 4.5 N). Neither non-grooved nor grooved TT samples failed under cyclic compression testing (100,000 cycles at 1 Hz). Compared with control specimens, LIM TT constructs exhibited higher load to failure under static compression and higher strain at the bone interface under cyclic compression. Laser-induced microgrooving has the potential to improve the performance of cemented orthopedic implants.Publication Stress analysis of additive manufactured lightweight spur gears(Amer Soc Mechanical Engineers, 2021-01-01) Ekwaro-Osire, Stephen; Yılmaz, Tufan Gürkan; YILMAZ, TUFAN GÜRKAN; Kalay, Onur Can; Karpat, Fatih; KARPAT, FATİH; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi.; 0000-0003-3772-7871; 0000-0001-8643-6910; 0000-0001-8474-7328; 0000-0002-9548-8648; V-6153-2017; A-5259-2018Additive manufacturing processes (AMP) have grown and spread in the last twenty years. Additive manufacturing methods, which were first used for plastic materials, are now increasingly finding a place in metals. With these methods, more lightweight component designs which cannot be generated with traditional methods can be manufactured. With the spreading of electric drive vehicles, weight reduction is becoming more important since weight is primarily responsible for energy consumption. There is a one-stage gear system in electric vehicles in general. For this reason, the subject of reducing the mass of gears is gaining importance. The weight reduction can be achieved with holes and slots on the gear body for involute spur gears or reducing gear web thickness. Several optimization methods can be used for this aim. Another way is to use light materials for the gear body, while steel material is used in the tooth-rim region. Carbon fiber composites are preferred for this purpose. However, using adhesives to join steel and carbon fiber reinforced plastics may cause problems in different environmental conditions. On the other side, parts are generated with single material with AMP methods. In this study, involute spur gears with different designs convenient for generation by AMP are created in a 3D CAD program. The involute tooth region is defined as design space. The effects of different designs on root stress and tooth stiffness are investigated by finite element analyses. For this purpose, the mathematical modeling of involute spur gear is set to get points of a tooth based on Litvin's approach in MATLAB. A point cloud code is obtained and imported to the 3D CAD program. After that, three teeth 3D finite element spur gear models are generated. Static analyses are conducted in ANSYS. Meshing force is implemented on the highest point single tooth contact line. Root stress value is the most important reason for tooth root fatigue, one of the most common failure modes of involute spur gears. Tooth deflection and stiffness are significant parameters for the dynamic behavior of involute spur gears. The tooth stiffness affects mesh stiffness and transmission error which are the primary source of gear whine. For these reasons, tooth root stress and tooth deflection values should be determined for different gear designs.In this study, stress analyses of additive manufactured gears are conducted with the finite element method. The effect of shell thickness, infill radius, and infill stiffener on tooth root stress and deformation is recorded. According to the results, shell thickness is the most effective parameter on the root stress and deformation. It is followed by infill orientation angle and infill radius, respectively.Publication Stress and mesh stiffness evaluation of bimaterial spur gears(Amer Soc Mechanical Engineers, 2019-01-01) Karpat, Fatih; Yılmaz, Tufan Gürkan; Doğan, Oğuz; Kalay, Onur Can; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi.Lightweight spur gears have been a trending topic in aerospace and automotive applications recently. Traditionally, weight reduction could be ensured by using gear body with holes or thin rim design which result in to fluctuate mesh stiffness or it may increase stress and deformation levels. Indeed, high stresses occur in only contact and root region of gear tooth during the meshing process, so other regions are subjected to low stress. Based upon this point; various materials with low density and adequate strength could be used in low stress region while gear steel remains for high stress region. In this study, two different lightweight materials (Aluminum alloy and Carbon fiber reinforced polymer) were used for low stress region. The effect of these materials was investigated in view of stiffness and root stress for the same gear design parameters. Unidirectional CFRP laminas were used in a symmetric lay up to ensure quasi-isotropic laminate properties. Finite element analyses were conducted to obtain root stress and then total deformation of the tooth for stiffness calculation. Interface properties of ring and core regions were assumed as pure bonded. Meshing load was applied on the highest point single tooth contact (HPSTC) line. Weight reduction ratios were also compared. According to results, the steel/composite design is superior to steel/aluminum hybrid design in view of stress, stiffness and weight.Publication The effect of hamatum curvature angle on carpal tunnel volumetry: A mathematical simulation model(Hindawi Ltd, 2020-03-10) Akdağ, Gökhan; Alp, Nazmi Bülent; Kaleli, Tufan; KALELİ, HÜSEYİN TUFAN; Kalay, Onur Can; Karpat, Fatih; KARPAT, FATİH; Macunluoğlu, Aslı Ceren; Oral, Gamze Saygı; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Ortopedi Anabilim Dalı.; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Biyoistatistik Anabilim Dalı.; 0000-0003-3656-0088; 0000-0003-1109-8958; 0000-0001-8643-6910; 0000-0001-8474-7328; 0000-0002-6802-5998; AAB-6136-2022; A-5259-2018In carpal tunnel volume measurements, the angle of the hamatum curvature is not considered a variable, and its effect on carpal tunnel volume has not been investigated. We hypothesize that a change in the anatomical angle of the hamatum curvature changes the carpal tunnel volume. To prove our hypothesis, we used a mathematical simulation model considering the carpal tunnel as a truncated cone. We reviewed the wrist CT scans of 91 adults (>18 years of age), including 51 men and 40 women. We measured the angle of the hamatum curvature in the CT scans. We measured cross-sectional areas at the outlet of the carpal tunnel at the level of the trapezium and hook of hamate (r1) and at the inlet at the level of the scaphoid and pisiform (r2) and the length (h) of the carpal tunnel. We attempted to calculate the effect of 2 degree by 2-degree changes in the angle of the hamatum curvature between the angles of 98 degrees and 140 degrees on the carpal tunnel volume. The mean angle of the hook of hamatum of the subjects was 122.55 degrees +/- 8.20 degrees (range, 97.20 degrees-139.31 degrees). No suitable cutoff point was found for the angle values. There was no difference between the gender groups according to the angle value. The data clearly show that there is a high correlation between carpal tunnel volume and the angle of hamatum curvature. The results of our study emphasize the importance of taking into account the anatomical features of the hamatum bone, especially the angle of curvature, which may play a predisposing role in idiopathic carpal tunnel syndrome.Item Ulaştırma alanında kullanılan dişli çark mekanizmalarında diş dibi çatlak hasarının ve derecesinin tespiti için makine öğrenmesi esaslı güvenilir bir izleme yönteminin geliştirilmesi(Bursa Uludağ Üniversitesi, 2023) Kalay, Onur Can; Karpat, Fatih; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Makine Mühendisliği Anabilim Dalı.; 0000-0001-8643-6910Dişli çarklar modern endüstride güç ve hareket iletmek için kullanılan temel makine elemanlarıdır. Dişli çarkların sağlık durumlarının izlenmesi ise (1) güvenilir operasyonlar sağlamak, (2) plansız duruşları önlemek ve (3) insan kayıplarını en aza indirmek için son derece kritiktir. Bu bakış açısından hareketle, mevcut tez çalışması standart (simetrik) ve asimetrik evolvent düz diş dişli çark çiftlerinde meydana gelen diş dibi çatlağı hasarlarını teşhis etmek için bir tek boyutlu evrişimsel sinir ağları modeli önermiştir. Mevcut tez çalışması dâhilinde sağlıklı ve çatlaklı standart (20°/20°) ve asimetrik (20°/25° ve 20°/30°) düz dişli çiftlerinin titreşim cevabını simüle etmek için tek kademeli bir düz dişli çark mekanizmasının altı serbestlik dereceli dinamik modeli oluşturulmuştur. Erken hata teşhisi görevini karmaşık hale getirmek için elde edilen titreşim verilerine üç farklı seviyede sinyal-gürültü oranı eklenmiştir. Bu tez çalışmasının ana düşüncesi; asimetrik dişlilerin dinamik özelliklerinin incelenmesinin yanı sıra diş asimetrisinin darbe direnci, eğilme mukavemeti ve yorulma ömrü bakımından sağladığı iyileştirmelere ek olarak diş dibi çatlaklarını derin öğrenme temelli bir yaklaşım ile daha kolay tespit etmede bir avantaj sağlayıp sağlamayacağını araştırmaktır. Tez çalışması kapsamında aynı zamanda değişken çalışma koşullarının ve diş dibi çatlağı hasarının düz dişli çark çiftlerinin titreşim cevabı üzerindeki etkilerini değerlendirmek için özgün bir dişli hata tespiti deney düzeneği kurgulanmış ve üretilmiştir. Deney düzeneği (1) bir elektrik motoru, (2) iki adet torkmetre, (3) bir dişli kutusu, (4) iki adet üç eksenli ivmeölçer ve (5) bir fren ünitesinden oluşmaktadır. Bu kapsamda, geliştirilen derin öğrenme temelli algoritmanın etkinliği fiziksel bir test düzeneği aracılığı ile toplanan titreşim verileri üzerinde test edilmeden önce (1) Case Western Reserve University ve (2) Paderborn University açık erişim veri setleri üzerinde koşturulmuştur. Elde edilen bulguların diş asimetrisinin dişli dinamik özellikleri ve erken hata teşhisi üzerindeki etkilerinin daha iyi anlaşılması için önemli çıktılar sağlaması hedeflenmiştir.Item Understanding the causes behind coracoid graft osteolysis in latarjet procedure (finite element analysis and comparison of three fixation methods)(Elsevier, 2020-02) Moussa, Abdellah Ait; Khandaker, Morshed; Akdağ, Gökhan; Alp, Nazmi Bülent; Yılmaz, Tufan Gürkan; Kalay, Onur Can; Karpat, Fatih; Doğan, Oğuz; Uludağ Üniversitesi/Tıp Fakültesi/Ortopedi ve Travmatoloji Anabilim Dalı.; Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0003-3772-7871; 0000-0001-8474-7328; 0000-0003-4203-8237; DXD-5241-2022; V-6153-2017; GDQ-4936-2022; A-5259-2018; AAV-7897-2020; 57195293117; 57194528723; 55807371600; 24366799400; 7006415878Background: Latarjet is one of the most common surgical procedure performed on patients with shoulder instability with osseous defects, some complications include coracoid bone graft osteolysis, osteoarthritis, graft detachment, and malpositioning were previously reported. Several studies investigated potential causes of graft osteolysis but still, it remains a crucial area of investigation. We aim to use finite element analysis to examine the potential correlations between three modes of fixation methods used in the Latarjet procedure (screw, wedge plate, and endobutton), and the coracoid graft osteolysis. Hypothesis: Finite element analysis tested the hypothesis that there is a linear relationship between the compression stress on graft which was generated by fixation methods used in the latarjet and the coracoid graft osteolysis. Material and methods: Boundary conditions and inhomogeneous material properties were carefully assigned within the material of the scapula and coracoid interface. For the screw and wedge plate fixations, an applied torque in the range of 1-1.5 Nm was used to characterize the surgeon's insertion torque during the surgical operation, while a 100 N compressive force was selected for the endobutton fixation. Results: Relatively lesser stress magnitudes were observed with endobutton fixation method rather than screw and the wedge plate fixation. Statistical analyses revealed significant differences between the groups (p<0.05). Discussion: Excessive compressive stresses within the coracoid graft regions may be responsible for osteolysis due to negative effects over biological factors such as blood flow. Our study emphasizes the importance of taking into account the fixation method while performing the Latarjet procedure. We concluded that the mode of fixation used within the Latarjet procedure has a correlation on the coracoid graft osteolysis.