Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Developing the Mechanical Properties of Bio-Based Films Used in Food Packaging Industry(Izmir Institute of Technology, 2023) Irak, Ekrem Anıl; Toksoy, Muhammet Fati̇h; Tihminlioğlu, Funda; 01. Izmir Institute of TechnologyCanlı popülasyonun artmasıyla birlikte dünyamızda atık yönetimi günden günde daha önemli bir hale gelmektedir. Sürdürülebilirlik için ambalaj atığı yönetiminde de birçok yöntem gündeme gelmiştir. Bu popülaritesi artan yöntemlerden biri de biyobozunma ile atık bertaraf edilmesidir. Yapılan bu çalışmada da biyobazlı ve biyobozunur ambalaj üretimi üzerine çalışılmıştır. Markette en yaygın olan biyobazlı ve biyobozunur ambalaj filmi PLA granülünden üretilen filmlerdir. PLA filmi mekanik özellikleri bakımdan petrol bazlı granüllerden üretilen birçok filme göre daha rijit ve şekil verilmesi zordur. Bu da paketleme makinalarında ambalaj filmine form vererek torba haline getirilmesinde kopma ve şekil verilmesi verimliliği kaynaklı problemler çıkarmaktadır. Bu problemler üzerine odaklanılarak PLA filmin rijitliğini bir miktar azaltmak için alışveriş torbalarında kullanılan Mater-Bi granülü kullanılmıştır. Mater-Bi granülünden üretilen alışveriş torbaları petrol bazlı standart ambalaj filmlerine göre daha sünek bir yapıdadır. Mater-Bi granülü de PLA granülü gibi hem biyobazlı hem de biyobozunur yapıdadır. Hem PLA hem de Mater-Bi granülleri solvente çözülüp %100PLA, %80PLA-%20Mater-Bi, %70PLA-%30Mater-Bi, %60PLA-%40Mater-Bi ve %100 Mater-Bi olarak farklı oranlarda ambalaj filmi üretilmiştir. Bu oranlarda üretilen ambalaj filmindeki Mater-Bi oranının artışı ile ambalajın özelliklerindeki değişim incelenmiştir. Mekanik özellikler kapsamında kalınlık, birim ağırlık, verimlilik, çekme-gerdirme dayanımı, delinme direncine bakılmıştır. Form verilen filmlerin yapışma performansı da gıda güvenliği için önemli bir kriter olduğundan dolayı yapışma performansındaki değişim de test edilmiştir. Gıda güvenliği ve raf ömrü için kullanılan ambalaj filminin diğer bir amacı da pazarlamadır. Bu sebeple üretilen ambalaj filminin optik özelliklerindeki değişim de test sonuçlarında bulunmaktadır. PLA'nın transparan görünüşü ile Mater-Bi'nin sarımtırak görünüşü arası optik özellikte filmler üretilmiştir. Farklı oranlarda üretilen ambalaj filmlerinin analitik olarak inceleyerek FTIR analizleri yapılmıştır. Gıda güvenliği açısından regülasyonlara uygun olduğunu görmek için solvent kalıntısı tespit testi yapılmıştır. Formülasyonlar yapılan testlerin sonuçlarına göre değerlendirilmiştir.Master Thesis Design of a Physical Human-Robot Interface for Lifting Operations(Izmir Institute of Technology, 2022) Dede, Mehmet İsmet Can; Dede, Mehmet İsmet Can; Dede, Mehmet İsmet Can; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this thesis, the design of a physical human-robot interface for lifting operations which controls the vertical movement of the payload is studied. The new design uses a low stiffness type of admittance control method that is aimed at reducing the surface impact force of the payload and providing better control for the operator while having the option of high stiffness admittance control. To reduce impact forces by using low stiffness admittance control, a sliding handle mechanism is introduced into the system. This type of design includes springs and bearings to create a low stiffness admittance-type user interface. Mathematical models are developed to calculate spring forces and mechanical strength. According to design requirements and mathematical calculations, the prototype is designed and manufactured. In the tests, it is seen that the spring forces are low, and the sliding motion of the handle is not consistent over different displacements. According to the test results, revisions are done, and the final design of the system is developed. In the final tests, it is seen that the new design of the physical human-robot interface performance is improved and the problem of the sliding motion of the handle is solved. Also, the surface impact forces are reduced with low stiffness admittance control. Another improvement of the new design is the ability to control the payload with high stiffness admittance control if the user chooses it. With this option, users can control the payload by touching the payload. Having both types of control methods, the user can choose which type of control method to use to handle payload in the factory.Master Thesis Numerical and Experimental Investigation of an Electric Vehicle Battery Module Thermal Management System(Izmir Institute of Technology, 2022) Çetkin, Erdal; Çetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyToday, electric vehicles play an essential role in preventing pollution from fossil sources. Therefore, it is vital to develop battery technology in electric vehicles. The biggest problem experienced is the thermal runaways, which is a phenomenon that may cause burning and explosions following the decrease in battery capacities. The thermal runaway problem can be solved by using the thermal management system to keep the temperature range under control. In this study, a 6.7 kWh battery pack was produced. Battery pack operation consists of two parts, mechanical and thermal. In the mechanical part, battery pack assembly and drop tests, one of the mechanical tests, were carried out. At the end of the battery pack assembly, voltage measurements were made, and the accuracy of the assembly was demonstrated. Besides, a numerical and experimental study supported drop tests. As a result of this study, the battery case did not show permanent deformation (2.529x 108 N/m2) as suggested in the numerical experiments (1.263x 108 N/m2). Discharge characteristics and battery module model were discussed in the thermal management part. The information in the literature confirmed the discharge characteristic. The gap between the battery cells reached its most efficient value at 8 mm. In the developed battery module, thermal management was attempted using a heat plate and a cooling pipe. According to the numerical results, the battery module reaches 311.37K at 10C discharge. In the experimental process, the battery pack was charged with 15 amps and discharged with 30 amps. Moreover, the temperature values reached a maximum of 31 degrees. In the experiment on electric vehicles, a maximum discharge level of 255 A was observed. In this experiment, the battery pack reached a maximum of 36 degrees.Master Thesis Touch Gestures Classification by Deep Learning Methods(Izmir Institute of Technology, 2022) Ege, Irmak; Altun, Kerem; Altun, Kerem; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, we carried out social touch gesture classification on two publicly available datasets, Corpus of Social Touch (CoST) and Human-Animal Affective Robot Touch (HAART), and our demo dataset. In order to classify touch gesture datasets, four different models are proposed: 3-dimensional convolutional neural network (3D-CNN), 3-dimensional convolutional-long term short term memory neural network (3D-CNNLSTM), 3-dimensional convolutional-bidirectional long term short term memory neural network (3D-CNN-BiLSTM) + and 3-dimensional convolutional transformers network (3D-CNN-Transformer). The fundamental layer of the proposed deep neural network architectures is 3-dimensional convolution layer that enables to extract spatio-temporal features of touch gestures. In this regard, with the use of spatio-temporal features of touch gestures, generalization performance of proposed four models have been improved using data augmentation techniques by applying randomly shift and rotation, and ensemble learning. Additionally, We also found out that Stochastic Gradient Descent (SGD) optimization algorithm has better generalization performance than Adaptive Moment Estimation (ADAM), which is used more frequently in deep learning. The accuracy of classification results of three dataset is investigated in terms of proposed model. The results showed that the proposed methods, especially ensemble classifier and the ensemble classifier with data augmentation, are beneficial for obtaining more generalizable learning algorithms. The scripts of deep neural network architecture are available upon request.Master Thesis The Effect of Strain Rate on the Deformation Behavior of Additively Manufactured Short Carbon Fiber Reinforced Polyamide Composites(Izmir Institute of Technology, 2022) Güden, Mustafa; Zeybek, Mehmet Kaan; Güden, Mustafa; 01. Izmir Institute of Technology; 03.10. Department of Mechanical Engineering; 03. Faculty of EngineeringThe compression behavior of Polyamide 6 (PA6- nylon 6) and short carbon fiber reinforced polyamide 6 (Onyx) produced by the Fused Deposition Modelling (FDM) method was investigated at both quasi-static and dynamic strain rates. The effects of layer height, specimen shape and dimensions, build direction and the orientation of the layers on the compression behavior were also determined. The results showed that the addition of short carbon fibers to the PA6 matrix increased the compression strength by 3-4 times and the determined flow stress has a strong correlation with the porosity amount in the specimens. The compression test results showed that cylindrical specimens had slightly higher flow stress than the cubic specimens. The compression tests on the specimens produced with different lengths showed almost no difference regarding stress-strain behavior. Furthermore, the specimens produced with 90 degrees showed the highest elastic modulus and yield strength and the specimens produced with 30 and 60 degrees the lowest modulus and yield strength. The Concentric infill specimens exhibited higher elastic modulus values and flow stresses than Cross raster infill specimens at all strain rates. In the layers of concentric rings, the outer rings prevented the lateral expansion of inner rings, leading to higher flow stresses than the cross raster [0/90] lay-up. The flow stress of both PA6 and Onyx specimens increased with increasing strain rate. The rate sensitivities of PA6 and Onyx specimens were shown to be similar to each other.Master Thesis Numerical Investigation of Various Heat Transfer Mechanisms on Thermal Management of a Lithium-Ion Battery Pack(Izmir Institute of Technology, 2022) Çetkin, Erdal; Çetkin, Erdal; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyLithium-ion battery packs are preferred in Electrical and Hybrid Vehicles (EVs and HEVs) due to their efficient and stable energy storage characteristics. Battery Thermal Management Systems (BTMS) have vital importance in EVs and HEVs to keep the batteries in desired temperature range to maximize performance and lifetime. Air cooling is a well-known method with the advantages of being simple and light but main concern for air cooling is effectiveness and pressure drops due to low heat capacity and thermal conductivity of air. This work compared various cooling designs for battery modules based on the surface temperature of batteries and the parasitic power consumption. Modules were built with COMSOL Multiphysics 5.5, and their accuracy was validated by experiments. Each module involves an equal number of batteries whose thermal characteristics were simulated by the electrochemical-thermal battery model, the P3D multiscale model. As a result, the maximum temperature was reduced by 5% (1.8°C) for inline alignment with baffles and 7.2% (2.8°C) for staggered modules, and the temperature gradient was reduced by 40% (1.7°C) for inline and 35% (1.5°C) for staggered alignments. While fan power consumption of inline alignment with triangle baffles (0.98W) was 3.5 times higher than the base design (0.27W), it was 0.23W for staggered design. Moreover, the cooling performance of different winglet parameters was compared and documented.Master Thesis Design of Stacker Crane for Mini-Load Automated Storage and Retrieval Systems(Izmir Institute of Technology, 2022) Mihçin, Şenay; Mihçin, Şenay; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe objection of the thesis is to design and analyze a 3 degree of freedom stacker crane mechanism for Mini Load Automated Storage and Retrieval Systems. Automated Storage and Retrieval System (AS/RS) is an automated system in which the product of a company to be stored is placed in or retrieved from specified location on a rack system by means of computer aided mechanism which is nothing but a stacker crane. This study first introduces an inclusive literature review on AS/RSs. Several types of AS/RSs are examined and the differences between them are introduced. Additionally, several types of stacker cranes in the literature are also presented. Moreover, the linear motion systems used in similar mechanism are explained briefly in the chapter. In the design chapter of the thesis, theory of the stacker crane mechanism is introduced. A conceptual design is created and, elements and sub-sections of the desired mechanism are presented with the conceptual design of the mechanism. After the conceptual design, critical design calculations are performed approximately before the detailed design of the mechanism. Afterwards, the detailed design of the mechanism is created and calculations are verified due to detailed design. The detailed design of the mechanism is analyzed using Finite Element Analysis methods in the analysis chapter of the thesis. Analysis of critical components and critical sub-sections of the stacker crane mechanism are analyzed using Computer Aided Engineering program. Revises are made according to the results of the FEA and design is validated at the end. At the prototyping chapter of the thesis, the manufacturing studies of the mechanism are presented. Manufacturing stages are introduced and experiments of the sub-section of the mechanism are done.Master Thesis Development of Joining Techniques for Carbon Fiber Based Polymer Matrix Composites(Izmir Institute of Technology, 2020) Tanoğlu, Metin; Tanoğlu, Metin; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn recent years, adhesive bonding has been a promising joining technology for CFRP composites. An appropriate treatment of surfaces for adhesive bonding is one of the effective factors for obtaining a high-quality adhesion strength. However, the adhesion strength is decreased by contaminants, like release agents, as well as an excess of matrix in the top layer. The contact of the adhesive with the reinforcing element is critical. Therefore, it is necessary to make a pre-preparation process on the adherent surface. One of the surface treatments preferred due to the advantages it provides is laser processing. The joint area strength of CFRP (carbon fiber reinforced polymer) composite can be enhanced with laser surface treatment. In this work, the carbon fiber/epoxy composites surface treatment by a nanosecond (1064nm wavelength) laser has been investigated. The polymer layer (epoxy matrix) on the CFRP (carbon fiber reinforced polymer) composite surface was selectively removed by laser treatment to expose carbon fibers. In order to remove the epoxy from the surface sufficiently, laser surface modification parameters were investigated and their effects were examined. These parameters are laser power, frequency, scanning speed and offset distance, respectively. Epoxy removal and fibers damage was analyzed by optical microscope and SEM (scanning electron microscope). Contact angle tests were carried out to analyzed wettability effect on the laser parameters. Lap shear, charpy impact and double cantilever beam (DCB) tests were performed to examine the effect of laser surface modification on mechanical performance.Master Thesis Wearable Systems for Performance Assessment in Volleyball(Izmir Institute of Technology, 2022) Altun, Kerem; Altun, Kerem; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyNowadays, wearable sensors are used for many applications such as healthcare, animation, sports, to name but a few. In this study, they are used to recognize volleyball activities such as digs, blocks, serves and spikes. These activities are normally followed by statisticians on the field, their presences and frequencies are noted by them to be recorded at the match report. This study focuses on automating this procedure and identifying/recognizing them using wearable sensors. Five Xsens MTw Awinda sensors are used to collect data from 10 volleyball players (5 women and 5 men) who are between 19-21 ages and have 3-12 years of experience as an active player in volleyball. In this thesis, optimum number of sensors and their locations, effects of combinations of different features such as minimum, maximum values, means and variances of the raw data, impacts of combinations of different sub sensors such as accelerometer, gyroscope and magnetometer on the 4-class&10-class classification average accuracies are investigated. Two classification algorithms are applied with two different cross validation methods: For both cross validation methods, LDA (Linear Discriminant Analysis) produced better average accuracies than KNN (K Nearest Neighbor) where k value is taken as 5. The average accuracies for 4-class and 10-class classifications are respectively 99.56% and 89.56%. However, these results are respectively 92.39% and 66.08% for KNN (k=5).Master Thesis Function Generation Synthesis of Planar Mechanisms as a Mixed Problem of Correlation of Crank Angles and Dead-Center Design(Izmir Institute of Technology, 2022) Kiper, Gökhan; Kiper, Gökhan; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyKinematic synthesis of mechanisms is generally divided into three groups. One of them is function synthesis. In function synthesis, the design of correlation of crank angles and dead dead-center position stand out. These problems have been clearly defined and solved separately. But in some cases, problems may be encountered that require both correlation of crank angles and dead dead-center design. Such problems are called mixed function generation problems. In this thesis, an overview of these mixed function generation problems has been given and many problems have been solved analytically or semi-analytically. The solutions of all problems including three positions for the four-bar mechanism and the solution of a problem including four positions for a four-bar mechanism have been addressed. A problem including 3 positions and a problem including 4 positions for a slider-crank mechanism have been addressed. All solutions have been reduced to univariate equation and a fast solution has been found. Thus, link lengths can be found quickly by changing the problem inputs. Numerical solutions of all problems have been demonstrated using Excel.