Theses supervised by Dr. Öğr. Üyesi Yaser Alaıwı
17 theses · Altınbaş University
Innovative approaches to kinematic optimization and material design in robotic prosthetic arm
This thesis provides a thorough study of designing, modelling, and analyzing a 7-degree-of-freedom prosthetic arm. The research illustrates the use of suitable materials to enhance its mechanical efficiency. The research evaluates three distinct materials, that is, Alloy 6061 T6 made of Aluminum, (230 GPa) Epoxy Carbon UD (Uncured), and (65% long glass fibre) of Composite, epoxy, selected for their distinctive mechanical qualities and prospective applicability in prosthetics. The prosthetic arm's design was created with SolidWorks', and its structural performance was evaluated using ANSYS's Workbench under different loading situations. The research depends on tackling the important problem of balancing durability, weight, and strength in a 7-degree-of-freedom prosthetic arm modelling, a balance necessary for human convenience and efficiency. The key mechanical properties, including maximum von-mises stress, total deformation, strain energy equivalent elastic strain, and factor of safety of prosthetic arm, and comprehensive simulations evaluated each material. The findings indicated that although all three advanced materials display satisfactory performance, the Epoxy Carbon UD proved to be the optimal selection. This material displayed the optimal stiffness-to-weight ratio, which is also minimal deformation, and a greater safety factor, making it the most effective choice for the prosthetic arm. This study enhances prosthetic arm advancement by providing insights into choosing materials and optimizing designing. The research highlights the significance of employing sophisticated materials and modeling methodologies to develop prosthetic arm that perform structural requirements while improving the comprehensive experience for users. The thesis concludes with a recommendation for further research, encompassing the investigation of novel materials for composites, the incorporation of intelligent technologies, and the verification of the simulations outputs by physical form modelling
Yüksek hızlı insansız hava aracı modellemesi ve simülasyonu
Unmanned Aerial Vehicles (UAVs) have appeared as a pivotal industry in contemporary times, attributed to their adeptness at executing intricate tasks in both civilian and military domains without endangered human lives. Consequently, numerous researchers have passionately studied these aircraft. Especially under stringent and challenging conditions, to ascertain their structural integrity post-manufacture. The focal point of this thesis is an in-depth analysis of the Boeing X-45C aircraft, with particular emphasis on its fuselage. The aircraft will be meticulously designed and rendered using the SOLIDWORKS software, adhering to its authentic dimensions. After this design phase, the aircraft will be positioned within a precisely defined fluidic environment to facilitate a comprehensive CFD simulation using the ANSYS Fluent software, simulating the aircraft's flight at peak velocities. This will be followed by an FSI simulation, intertwining the insights gleaned from the CFD analysis with the potential ramifications on the aircraft's aluminium structure. The culmination of the thesis will present a thorough commentary on the results, evaluating the success and efficacy of the simulations and analyses conducted. The findings underscored the robustness of the aircraft, confirming its resilience under the tested conditions. Keywords: FSI,
Santrifüj pompalarda iki fazlı akış özelliklerinin sayısal incelenmesi
Due to its important applications, particularly in the oil and gas industry, two-phase pumping has been the subject of several studies. This study includes a numerical investigation of two-phase flow inside a centrifugal impeller with seven blades, at a rotational speed of 2500 rpm and an inlet pressure of 100000 Pa. The simulation includes investigating the effect of flow rate, gas volume fraction GVF, and bubble sizes on the pump performance curves and also on the phase distribution through the impeller. Four flow rate values of 2.4, 3.1, 3.9, and 4.6 kg/s, four GVF values of 0.1, 0.15, 0.2, and 0.3, and four bubble sizes of 0.1, 0.2, 0.3, and 0.5 mm are considered in the simulation. The governing equation and the turbulent kinetic energy dissipation (k - ε) model are solved using ANSYS software. The results show that increasing the flow rate leads to a decrease in the pump head and hydraulic efficiency under single- and two-phase operations, with reduced performance in the case of the two-phase condition. The head and efficiency are also significantly affected by increasing the GVF and bubble diameter. Increasing the GVF from 0.1 to 0.3 causes the head to decrease by about 26% and hydraulic efficiency by up to 25%. The impact of bubble size, on the other hand, depends on the flow rate and bubble diameter. A significant reduction in pump performance by increasing bubble diameter has been reported for low flow rates, while only a limited impact has been observed for high flow rates, particularly at large bubble sizes. Gas pocket formation has been visualized at the inlet upper pressure side of the impeller blade in cases of high GVF and bubble diameters.
Güneş enerjili sabit kanatlı bir İHA'nın dayanıklılık ve verimin artırılması için etkili faktörlerinin incelenmesi
This research aims to investigate effective factors for enhancing the performance and efficiency of fixed-wing solar-powered unmanned aerial vehicles (UAVs). The MQ-9 model was selected for analysis. SunPower C60 solar cells were integrated onto the entire wing surface through computer-aided design using SolidWorks. Calculations quantified additional energy harnessed, battery capacity for storage, and improvements in flight endurance and range. Findings reveal that augmenting the MQ-9 wings with high-efficiency photovoltaic cells substantially increased the solar-powered UAV's flight duration by approximately 30%. Conclusions confirm incorporating renewable solar energy enables notable efficiency gains in fixed-wing UAVs. This study paves the path for solar technology integration, moving towards environmentally sustainable aviation systems. Further work should assess cutting-edge solar cells, improved energy storage, extended operational flight times, and broader aerospace applications. In summary, by highlighting the immense potential of solar power in enhancing fixed-wing UAV efficiency. This research advocates solar-powered systems as pioneers for the future of unmanned flight technology.
Nano akışkanlar ile kabuk ve boru ısı eşanjörlerinin geliştirilmesine ilişkin karşılaştırmalı CFD hesaplamalı çalışması
This research investigates the enhancement of shell-and-tube heat exchanger efficiency using titanium dioxide (TiO2) nanofluids through a comparative computational fluid dynamics (CFD) analysis of two cases. In the first case, cold water flowing through the tubes is heated by hot water in the shell. The second case introduces a 0.5% TiO2 nanofluid mixture to hot water, aiming to investigate its impact on heat transfer efficiency. Utilizing computer-aided design (CAD), the study models an innovative heat exchanger configuration that closely mirrors commercial dimensions but incorporates slight variations to discover new design potentials. CFD modelling employs a grid independence approach to ensure the accuracy of the results. The findings indicate an 11.44% increase in cold fluid temperature rise with the nano fluid case, demonstrating significant efficiency improvements over conventional water usage. This highlights the potential of engineered nano fluids for enhancing industrial heat recovery processes. Leveraging CAD and CFD tools for optimized design, the detailed thermal performance analysis provides profound insights into the augmented heat transfer phenomena induced by nano fluids. This research contributes to the scientific understanding and development of efficient and sustainable thermal technologies, paving the way for advanced nanotechnology-enhanced heat transfer solutions with wide-ranging implications for energy efficiency across various sectors.
Uçak gemilerinde uçak kalkış performansının modellemesi ve simülasyonu
Catapult systems, a significant component of aircraft carriers, are utilized to accelerate the takeoff of aircraft and ensure their safe ascent from the vessel. These systems facilitate operational flexibility and efficiency by enabling aircraft to accelerate and take off over short distances. Catapult systems enhance the operational capacity of aircraft carriers by enabling aircraft to take off with heavier loads and over shorter distances. In line with this, within the scope of the thesis, suitable aerial vehicles for aircraft carriers have been modelled using MATLAB Simulink, and the accuracy of theoretical information has been observed. This research represents an important step in understanding the effects of catapult systems, a critical aspect of aircraft carriers, and aims to provide valuable contributions to future aircraft carrier designs.
Otonom su alti araçlarini (AUV) lattice ve topoloji optimizasyon teknikleri ile geliştirmek
This study investigates various advanced computational techniques in Lattice Optimization, aiming to maximize the hydrodynamic efficiency and structural design of the Autonomous Underwater Vehicles (AUV), to meet higher manoeuvrability performance, durability, and payload capacity. Our goal is focused on reaching a very compact AUV design with high manoeuvrability as a base model. ANSYS engineering simulation and N-Topology software were used to run rigorous Computational Fluid Dynamics (CFD) simulations, to assess the lattice configuration hydrodynamic performance. Lattice Optimization allows for incorporating more functions into AUV components by accommodating extra sensors and wiring while minimizing space usage. Five different AUV streamlined design shapes, inspired by the Crab Shell, Mantay Ray, Reduced size, Cockroach Shape, and Tube Shape were selected for the study. The five different iterations of fluid flow patterns were examined through different thrusters and flange design configurations, scoring the advantages, recording the flaws of each design, and presenting the results. The most effective lattice design was identified through the examination of the fluid flow patterns and drag coefficients, succeeding in reducing the hydrodynamic drag and improving overall AUV efficiency in underwater environment.
Hesaplamalı akışkanlar dinamiği (HAD) analizi kullanarak İHA kanat tasarımının aerodinamik optimizasyonu
This study presents a comprehensive investigation into the structural and aerodynamic performance of unmanned aerial vehicle (UAV) wings constructed from both traditional and composite materials. Specifically, the research focuses on three material configurations: conventional aluminum, Epoxy Sheet Molding Compound (SMC) reinforced with 65% long glass fibers, and Epoxy E-glass composites. The primary objective is to enhance the aerodynamic efficiency and structural integrity of UAV wings through optimal material selection. A detailed computational analysis was conducted utilizing Computational Fluid Dynamics (CFD) to evaluate aerodynamic forces such as lift and drag across all material cases. This was followed by a one-way Fluid-Structure Interaction (FSI) analysis to assess the structural responses of the wings under realistic flight conditions. Additionally, modal analysis was performed to determine the natural frequencies and mode shapes of the wing structures, identifying critical vibrational modes that could impact flight stability. The CFD analysis provided consistent aerodynamic load data for all material configurations, quantifying the forces acting on the wings. The subsequent FSI analysis offered insights into how each material handled stress distributions, deformation characteristics, and structural strains under operational loads. The results revealed significant differences among the materials in terms of safety factors, deformations, and natural frequency behaviors. Notably, the composite materials outperformed aluminum by exhibiting superior structural strength and reduced weight, leading to higher safety margins and improved resistance to vibrational stresses. Among the composites, the Epoxy E-glass material demonstrated the highest safety factor and the most balanced performance regarding stress distribution and deformation control, indicating its superiority for UAV wing design. This research underscores the critical importance of material selection in UAV design, particularly for wing structures where aerodynamic efficiency and structural durability are paramount. The findings provide valuable insights for future UAV developments, highlighting the potential of advanced composite materials to optimize performance, reduce structural weight, and ensure safer, more reliable operation under varying flight conditions.
Güneş hava ısıtıcısının verimlilik artırımında geometrik ve yapısal tasarımın araştırılması
This study aims to enhance the thermo-hydraulic performance of solar air heaters (SAHs) by employing various broken V-shaped artificial roughness configurations on the absorber plate, with and without incorporating grooves of triangular, semi-circular, and trapezoidal cross-sections. A three-dimensional numerical analysis was conducted using ANSYS Fluent software to examine the fluid flow and the heat transfer characteristics within a solar air heater duct with an aspect ratio of 12 and a hydraulic diameter of 0.046 m, across Reynolds numbers ranging from 3*103 to 15*103. Geometrical parameters of roughness are set to the optimized and best performance of related experimental validated set of parameters. The results indicate that there is significant increase of both heat transfer rates and friction losses of V-shaped ribs attributed to enhanced turbulence and vortex formation. Applying gaps in the V-ribs yield further enhancement in Nusselt numbers, accompanied by slight increase in friction factors. The maximum improvement in the Nusselt number reaches three times greater than that of a smooth duct, with an increase of THPP ranging from 2 to 2.15. Furthermore, the addition of grooves to the broken V-ribs configurations increases both Nusselt numbers and friction factors. For the semi-circular grooves, which provide the most favourable results, the Nusselt number reaches up to 1.25 times that of the corresponding arrangement without grooves, with only a slight increase in friction factors. THPP of the combined V-rib and groove arrangements significantly exceed those of other configurations, with maximum values observed for V-ribs combined with semi-circular grooves, ranging from 6.3 to 2.4, depending on the Reynolds number.
Analysis of bionic structural design of front car bumper using finite element method
In this study, the energy absorption impact of bionic bumpers has been analyzed using nonlinear finite element simulation. In a frontal collision, a moving rigid wall was used to impact the bumper beam. The design of the bionic structure was based on the 2019 KIA (optima) model, with the cross-sectional shape modified to a honeycomb structure. Computer simulations demonstrate that the design of bionic bumpers increases the absorbed energy of a bumper during high-velocity collisions. Changes in stresses and strains were also observed throughout the impact. The construction included the structural components of the 2019 KIA optima bumper's Honeycomb bumper and was made of a different kind of material (stainless steel AISI 304 and AL 7003). The results indicate that the bionic design improves the bumper's specific energy absorption (SEA). The stress and strain contours, the displacement of the node, which is on the deformation parts of the bumper beam, the amount of compression of the crash box, the process of energy conversion, etc. The maximum crush deformation of the Honeycomb (ST AISI304) cross-beam and box bumper models was reduced by a decrease of 47.18% and for (AL 7003) the reduction was less than (AISI304) by 11.089 %. As for the energy absorption capacity under the lateral impact, a bionic design can be used in the future bumper body. Finally, the thesis discusses the influence of factors on collision characteristics, such as the section shape and material properties of the bumper beam. The design and analysis of the bumper beam were subjected to offset impact loading using ANSYS-Explicit dynamics and suggested the best shape design. Also, the three bumpers' natural frequencies and mode shapes have been calculated.
Heat transfer model in a hot/cold food container using peltier
On a global scale it is considered that, a notable part of the overall electrical energy is consumed in refrigeration and air conditioning sectors. Refrigeration sector is also known as an important and critical industry in the field of food and pharmacy sectors. In general refrigeration and also freezing applications are based on the extracting thermal energy from the freezing or cooling medium to keep the temperature at the specified standard levels suitable for storage foods or medicines. Vapor compression refrigeration systems are mostly employed for cooling, heating and air conditioning purposes, but comparative investigations focused on thermoelectric devices and their efficiency with well-known vapor compression refrigeration systems are less regarded in the literature. In this study, Peltier thermoelectric performance was obtained in two different ways and the results were compared. First, the COP value was obtained when cooling was carried out in an insulated box and then in different mode, the heating of the box was carried out. It was observed a big difference between COP values of heating and cooling modes. According to the achieved experimental results of this study, the COP or coefficient of performance value in the heating mode is approximately 200% greater than that of cooling mode.
Heat transfer enhancement using ferro-nanofluid with megnatic field in tube having inserted twisted tube
Several research initiatives will investigate the application of nanofluids more fully in order to enhance its commercialisation. Over the past ten years, the usage of magnetic nanofluids for enhancing heat transfer has gradually grown as a result of its superior thermal conductivity compared to other nanofluids. Nanoparticles have a significant impact on the thermal properties of base fluids, such as thermal conductivity and viscosity. When nanofluids are used, the double-tube heat exchanger's ability to transmit heat is considerably enhanced. Other experiments showed that when the concentration of nanofluids was reduced, the heat transfer coefficient increased even more. As a result, more investigation was needed before using nanofluids in plate heat exchangers. The colloidal suspension's thermal properties essentially differ from those of the base fluid. In multi-component systems like colloidal suspensions, suspended particles interact with one another significantly. The major goals of the current work are to assess the improvement in heat transfer achieved by utilizing twisted tape and ferro-nanofluid, and to model the impact of a magnetic field on ferro-nanofluid on the rate of heat transfer. Studies in computational fluid dynamics (CFD) are conducted to have a deeper understanding of the field of the stream. The (k-ε) model is used to explain the effects of the disturbance model, which comprises the configuration of two vehicle conditions. Therefore, these Cartesian direction frameworks will be addressed by the mathematical arrangement's procedures (x, y, and z). Calculation with three layers is produced. The framework math will be created and networked using ANSYS software, after which one case will be replicated. The mathematical results for the process of improving heat transfer utilizing twisted tape and ferro-nanofluid with the effects of several conditions: rotational cycle, magnetic field intensity, and concentration of ferro-nanofluid when using ferro-nanofluid with a magnetic field to improve heat transfer, the influence of the aforementioned conditions on pressure, temperature, and fluid velocity is also evident. The findings demonstrate that for all operating circumstances, fluid pressure decreases while velocity increases and temperature rises uniformly.
Thermal efficiency analysis of a double pipe heats exchanger using silver nanoparticles suspended in pure water
The thesis aimed to conduct an experimental study to improve the effectiveness of the double tube heats exchanger with a counter flow of 1 m in length, the outer tube 19 mm in diameter and the inner tube of copper 9.5 mm in diameter, using Nano-fluids as a cold fluid. Silver oxide nanoparticles with a diameter of 40 mm and a volumetric concentration of 0.2 % and 0.1 % were used with a water as a basic liquid. The cold Nano-fluids flows inside the inner tube at a volumetric flux rate of 3Litre/minute, 5Litre/minute and 7Litre/minute, which enter the heats exchanger at 15 °C ±1, while the hot water flows through the space between the two tubes at a volumetric flux rate of 5 L/minute and enters the heats exchanger at a temperature of 60 °C ±1. The experimental results obtained using this type of Nano-fluids were compared with the use of water to obtain a better efficiency of the heats exchanger. The obtained results showed an improvement in the efficiency of using Nano-fluids. The maximum percentage of improving effectiveness when using silver oxide with water was 28 % at a volumetric concentration of 0.2 % at a volumetric flow rate of 3 litres / minutes. This study showed that the "(density, thermals conductivity, and viscosity) of the Nano-fluids increases with the increase in the volumetric ratio of the solid "nanoparticles".
Thermal effect reduction in electrical vehicle battery using liquid cooling techniques
The electrical vehicles were used new techniques to improve the boundary condition for work operation of lithium-ion battery which is consider main source for EV's to storage energy and feeding the power to the electrical engine and appliance of it. The lithium-ion battery has operating temperature start from 0 to 35 ℃ degrees, but the ideal range start 16 to25 ℃ degrees. In the researcher focus on change in perspective of thermal management system that control to the cooling lithium-ion battery packs which is related and effecting on battery performance depending on heat transfer medium such as air, liquid or air-liquid or depending on the techniques of cooling such as liquid jacket, cold plate, micro channel, serpentine channel cooling plates, submerge battery packs in coolant. all these types discussed the cooling system and how maintain the batteries near to operating thermal range. To make this research go forward, we will discuss the techniques of reducing the different temperature by using cooling liquid medium and these techniques improved to reduction the thermal effect by uniform distribution techniques to achieve the best cooling distribution around the batteries. In present work, the our model results proved that the temperature under controlled at many different discharge load (1C,0.6C,0.667C,0.7C,0.88C) C-rates Tmax was controlled at 33.82 °C and ∆ Tmax =3.18 °C , ambient temperature (26.5°C).
Cad integrated design and analysis of compound die
Sac metal, çok yönlülüğü nedeniyle çeşitli günlük uygulamalarda yaygın olarak kullanılan bir malzemedir. Araştırmacılar, bükme ve kesme teknikleri dahil olmak üzere metal levhaların farklı yönlerini keşfetmeye büyük ilgi gösterdiler. Bu araştırmanın amacı, sac metal imalat endüstrisinde yaygın olarak kullanılan bir bileşik kalıbın kapsamlı bir tasarımını ve analizini yapmaktır. Çalışma, piyasadan belirli özelliklere sahip belirli bir ürünün seçilmesini ve ardından seçilen ürünün ayrıntılı bir SOLIDWORKS çiziminin oluşturulmasını içerecektir. Daha sonra kalıbı tasarlamak için matematiksel denklemler kullanılacak ve kesme kuvvetlerinin kalıp parçaları üzerindeki etkisi göz önünde bulundurularak her bir bileşen için en uygun kalınlık belirlenecektir. Her kalıp bileşeninin işlevi de açıklanacaktır. Akabinde, komple kalıp tasarımı SOLIDWORKS yazılımı kullanılarak gerçekleştirilecek ve yapısal bütünlüğünü sağlamak için ANSYS Workbench yazılımı kullanılarak bir sonlu eleman analizi gerçekleştirilecek ve burada maksimum gerilmeler, toplam deformasyonlar, güvenlik faktörü hesaplanacaktır. ve maksimum elastik gerinim ile ömrü.
Experimental investigation of swirl flow and heat transfer in concentric cylinders
The heat transmission and flow structure of a whirling impinging jet on a flat surface with helicoid inserts are investigated both experimentally and numerically. The research focuses on flow dynamics in order to characterize the effect of swirl on impingement mechanics by modifying the number of helicoid surfaces known as single, double, and triple helicoid inserts. The goals for this project were to first simulate a viscous, low Reynolds number flow around a cylinder (Part 1) and then simulate a similar flow around an arbitrary geometry (Part 2). In Part 2, the group was interested in determining if the heat transfer increased due to the addition of a line of solid material attached to the downstream side of the cylinder at the center line. The first part of this project was used to make sure that there was a working simulation, which could test a more interesting geometry in Part 2. For this project, the hypothesis was that the heat transfer would increase due to the reduction in separation of the flow on the downstream side of the cylinder. The main assumptions and restrictions were that the flow is of a low Reynolds number and there is only two-dimensional heat transfer. The method used was a two-dimensional stream-function/vorticity finite difference model of governing equations with a Cartesian basis.
Hydrogen as storage to generate power and with the help of fuel cell technology
This thesis presents a design of a Solar-hydrogen hybrid system (SHHS) for a domestic household. The objective is to develop a system that can provide continuous electricity throughout the year in the presence of grid and solar intermittencies. The SHHS comprises components such as Photovoltaic (PV) panels, PEM-based. electrolyzers, PEM-based. Fuel-cells, hydrogen-tanks, Lithium-ion batteries, controllers, and auxiliary equipment like DC/AC converters or charge controllers. This research aims to determine the optimal configuration and sizing of system components to achieve high performance at a low cost, considering different. user needs and control strategies. The MATLAB SIMULINK is utilized for the full system design. and simulations. The models for the PV-panels, PEM electrolyzers, control strategies, and energy management for a typical home are verified through simulations. All the developed models are integrated into SIMULINK, verifying that the household's electricity demand is met directly from the PV-arrays or with the assistance of batteries. and fuel-cells when. solar energy and grid power are insufficient. Key design parameters in this study include the pressure level. in the hydrogen tanks and the overall system efficiency. The analysis focuses on component parameters and various control strategies that impact the pressure in the hydrogen tanks and the system's efficiency.