Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Piezoelectric energy harvesters in bridge structures: Evaluation of optimal placement and energy harvesting
Sen, Bugra; Polat, Alper; Kapicioglu, Abdullah; Esen, Hikmet
In the present study, energy is harvested from vibrations in bridge structures caused by vehicle passages using piezoelectric energy harvesters (PEHs). In order to maximize the energy harvested, it was aimed to specify the optimal locations of PEHs. In the study, energy harvesting from vibrations in bridge structures was achieved using three different vehicle loads and three different piezoelectric materials. The project of the Ku & scedil;saray & imath;-2 bridge, located in Ku & scedil;saray & imath; village in Baskil, Elaz & imath;& gbreve;, was modelled in the ANSYS program using real measurements. The bridge was analyzed for modal, harmonic, and piezoelectric energy harvesting, respectively. The type with the highest energy production was determined using three different piezoelectric materials (PZT-4, PZT-5A, and PZT-8) for a total of 9 PEHs, and a total of 13 different analyses were performed under three different vehicle loads (60 kN, 90 kN, and 120 kN) to compare the results. The maximum total power obtained from all nine PEHs was 1.484 & micro;W under the 120 kN load with PZT-5A. The maximum power obtained from a single PEH (PEH-1) was 0.49 & micro;W. This power achieved will be adequate for wireless sensor systems used for monitoring the structural health of bridges, and considering that energy harvesting through vibration is independent of meteorological elements, unlike energy sources such as solar and wind, the environmental damage caused by waste batteries in existing systems will be prevented with the dissemination of these systems. With the development of these systems, the energy needs of services such as lighting and traffic signs can be supplied. The results provide an important foundation for the development of vibration-based energy harvesting systems in bridge structures. Thus, the study stands out as an innovative step toward sustainable energy generation in structural engineering.
- MakaleYayıncıda açık erişim2026Scopus SJRQ1Experimental study of an alternative precast concrete beam–column connection with embedded steel block detail
Baltaci, Alihan; Sunca, Fezayil; Şahi̇n, Muhammed Cihat; Şen, Doğa; Keçeci̇, Bedirhan; Polat, Alper; Altunişik, Ahmet Can
Precast systems have gained increasing popularity due to their advantages in construction speed, cost efficiency, and quality control. However, past earthquakes have revealed that beam–column connections are often the most vulnerable regions in precast structures, making their seismic performance a critical area of investigation. This study investigates the cyclic behavior of two full-scale precast specimens with different beam–column connection configurations: a code-compliant, Moment-Resisting Emulative-Welded Connection detail (MRCON) and an alternative Embedded Steel Block Connection detail (ESBCON). Both specimens were tested under quasi-static reversed cyclic loading to evaluate their hysteretic response, energy dissipation, stiffness degradation, residual displacements, and modal characteristics. The results demonstrate that while MRCON provided higher initial stiffness and energy dissipation, it experienced severe localized damage and rapid structural deterioration at larger drift ratios. In contrast, the embedded steel block in ESBCON successfully distributed the damage across a wider joint region, leading to a more gradual stiffness reduction and slightly lower residual displacements. Although the overall structural efficiency of ESBCON was partially hindered by the slippage of the steel block, it achieved a competitive level of moment transfer capacity compared to the conventional welded connection detail, highlighting its potential as a damage-distributing alternative once slip-mitigating modifications (surface roughening to enhance bond and embedding within the column) are implemented.
- MakaleYalnız künye2026Scopus SJRQ3Analytical Solution of Discontinuous Contact Problem in Functionally Graded Layer and Homogeneous Layer
Kaya, Yusuf; Polat, Alper; Şükrü Özşahin, Talat; Bora, Pınar
In the study, the problem of discontinuous contact in two layers, one of which is functionally graded is solved using the theory of elasticity. In this problem functionally graded (FG) layer resting on homogeneous layer and loaded with two different rigid flat blocks. In addition, homogeneous layer is resting on a rigid plane. Frictions on all surfaces are neglected. The heights of the FG layer and the homogeneous layer are h1 and h2, respectively. When solving the problem, displacement and stress equations are substituted in the boundary conditions. Then the problem is demained to singular integral equations. Wherein unknown functions are the contact stresses under the two rigid flat blocks and the slope of the separation. These singular integral equations are solved numerically using the Gauss- Chebyshev integration formulas. The analyzes were performed for different inhomogeneity parameter (βh1), shear modulus ratio (μ2/μ-h1). distance between the rigid blocks ((a3-a2)/h1) and density parameter (γh1). Consequently, the stress distributions and starting and ending points of the separation area between the FG layer and homogeneous layer are determined for several dimensionless quantities.
- MakaleYalnız künye2026Scopus SJRQ2Damage diagnosis in CFRP/Al7075-T6 aeronautical structures using piezoelectric sensors: characterization and experimental monitoring
Gahlouz, Ibtissem; Guemmour, Mohamed Boutkhil; Chellil, Sadek; Chellil, Ahmed; Houari, Amin; Aribi, Chouaib; Polat, Alper; Adjout, Warda; Bey, Mohamed
Purpose – This study aims to design a damage detection and characterization system (targeting cracks and delamination) for aeronautical composite structures. Design/methodology/approach – This methodology relies on a multidisciplinary approach combining polymer-reinforced/metallic carbon fiber hybrid structures with an integrated network of PZT sensors. It leverages experimental data and employs advanced signal processing and imaging techniques to monitor structural integrity and assess the severity of damage. Findings – Verified experimental results confirm the method's reliability in real-life situations. Research limitations/implications – Research Limits: “The primary challenges involve signal processing complexity due to the hybrid nature of AL7075-T6 and CFRP materials, as well as the potential influence of environmental factors (temperature, pressure) on PZT sensor reliability”. Research Implications: “This work enables a shift toward condition-based maintenance, significantly reducing operational costs while enhancing structural safety and extending the service life of critical aerospace and maritime assets.” Practical implications – This study enables a shift from scheduled to real-time structural monitoring. There is a drastic reduction in inspection time and aircraft downtime. Monitoring the fatigue of hybrid AL/CFRP structures helps to safely extend their service life. The study helps in providing precise diagnostics to optimize repair strategies and minimize human error. Social implications – There is a drastic reduction of structural failure risks through early-stage damage detection. Cost savings in maintenance can lead to more affordable air travel for the general public. The study helps in promoting a circular economy by safely extending the lifespan of complex structures and reducing material waste and also in shifting maintenance roles toward high-tech data analysis and specialized software expertise. Originality/value – The study investigates the complex damage mechanics at the interface of AL7075-T6 and CFRP laminates and helps in combining PZT sensor networks with advanced imaging software for real-time damage characterization. Beyond mere detection, the system assesses “structural criticality, ” providing high-value diagnostic data for maintenance optimization and cost reduction.
- MakaleYalnız künye2025The effect of electromagnetic fields on building materials: The case of base stations
Baran, Zeki; Polat, Alper
This study investigates the electromagnetic field (EMF) permeability characteristics of widely used construction materials to determine their effectiveness in electromagnetic insulation against radiation emitted by base stations. Field measurements were conducted at 81 base stations located in the city center of Diyarbak & imath;r in accordance with the standards of the Information and Communication metal, lead, PVC, XPS, and recycled concrete. The results indicate that the highest average electromagnetic field intensity was measured in free-space conditions (3.37 V/m), whereas lead exhibited the most effective shielding performance with an average value of 1.01 V/m, corresponding to an attenuation of approximately 70%. Metal sheets also showed strong shielding capability with an average value of 1.29 V/m. Among conventional materials, recycled concrete demonstrated lower electromagnetic permeability (2.13 V/m) compared to standard concrete (2.60 V/m). Thickness-dependent measurements revealed that increasing recycled concrete thickness from 3 cm to 7 cm reduced electromagnetic field intensity from up to 2.93 V/m to as low as 1.64 V/m, representing a reduction of approximately 44%. Measurements conducted inside and outside the safety distance further confirmed that EMF levels outside the safety distance can be more than twice those measured inside. Overall, the findings demonstrate that material type, thickness, and safety distance play a critical role in reducing electromagnetic exposure. Recycled concrete emerges as a sustainable and effective alternative for electromagnetic shielding in building design.
- MakaleYalnız künye2024Scopus SJRQ2Contact analysis in functionally graded layer loaded with circular two punches
Polat, Muhammed T.; Polat, Alper
In this study, contact analysis in a functionally graded (FG) layer loaded with two circular punches is solved using the finite element method (FEM). The problem is consisted of a functionally graded layer that resting on an elastic semi-infinite plane and is loaded with two rigid punches of circular geometry. External loads P and Q are transferred to the layer via two rigid punches. The finite element model of the functionally graded layer is created using the ANSYS package program and a 2-dimensional analysis of the problem is analyzed. The contact lengths, obtained as a result of the analysis are compared with the analytical solution in the literature. In the study, the effects of parameters such as distances between punches, loads, inhomogenity parameter on contact zones, initial separation loads and distances, normal stresses, stresses across depth and contact stresses are investigated. As a result, in this study, it can be said that the magnitude of the stresses occurring in the FG layer is less than the homogeneous layer, therefore the life of FG materials will be longer than the homogeneous layer. When the distance between the punches is 2.25, the initial separation distance is 6.98, and when the distance between the punches is 4, the initial separation distance decreases to 6.10. In addition, when the load increased in the second punch, the initial separation load decreased from 55 to 18. The obtained results are presented in the form of graphs and tables.
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İncele - MakaleYalnız künye2024Scopus SJRQ2Effect of repair patch nature on J-integral reduction in notched plates
Houari, Amin; Kouider, Madani; Polat, Alper; Amroune, Salah; Mohamad, Barhm Abdullah; Chellil, Ahmed; Campilho, Raul
Purpose: The purpose of this research is to evaluate the effectiveness of different repair patch materials in reducing the stresses at the crack tip of a 2024-T3 aluminum plate. This involves a numerical analysis using the finite element method (FEM) to estimate the reduction in the J-integral value, with the goal of identifying how various parameters related to the patch materials, adhesive properties and loading conditions influence the structural integrity of the repaired plate. Design/methodology/approach: The methodology of this research involves conducting a numerical analysis using the FEM to estimate the reduction in the J-integral value at the crack tip of a 2024-T3 aluminum plate. Three types of patches – metal, composite and functionally graded material (FGM) – were examined under tensile loading conditions, and Adekit-A140 adhesive was used to bond these repair patches to the aluminum plate. Findings: The analysis considered various parameters, including crack length, the nature of fibers in the composite material, the gradation exponent for FGM patches and the nature of the face in contact with the adhesive for the FGM patch. Additionally, stress analysis was conducted, examining the J-integral values for the plate, shear stress in the adhesive layer and peel stress in the composite patch. The findings highlight that modifying the nature of the repair patch used can significantly enhance the structural integrity of the repaired plate. Originality/value: The study analyzed J-integral values, shear stress in the adhesive and peel stress in the composite patch. Various parameters, including crack length, fiber type, gradation exponent and adhesive contact face nature, were considered. Results demonstrate that the J-integral value can be significantly reduced by altering the repair patch type, highlighting the effectiveness of customized patch materials in enhancing structural integrity.
AtıfScopus4OpenAlex6İncele - MakaleYalnız künye2023Scopus SJRQ2Anti-tank impact absorption with a reinforced concrete plate design
Polat, Berivan Yilmazer; Savaş, Sedat; Polat, Alper
Anti-tank weapons are among the infantry weapons used by the armies of many countries. Anti-tank rockets and explosives such as TNT, generally used for armour piercing, are also frequently used in terrorist attacks. These attacks damage the protection facilities built from reinforced concrete. Rockets or similar explosives’ rapid speed and burst temperatures pierce reinforced concrete during strikes, resulting in casualties and damage to crucial strategic structures. This study aimed to devise an economic and applicable reinforced concrete plate that could absorb the impact of anti-tank rockets and Trinitrotoluene (TNT) type explosives. Therefore, 5 different samples, produced from C50 reinforced concrete and 150×150 cm in size, were formed by combining plates of different numbers and thicknesses. Also, a sample, which was a single thick plate, was prepared. In destructive testing, Rocket Propelled Grenade (RPG-7) was used as the anti-tank rocket launcher. As a result of this study, the impact damage was reduced with hollow concrete plate geometries, and recommendations were developed for complete prevention.
AtıfScopus2WoS3İncele - MakaleYayıncıda açık erişim2023Estimation of Contact Lengths Using Deep Neural Network; [Derin Öğrenme Yöntemi ile Temas Uzunlukları Tahmini]
Polat, Alper
One of the most common problems in engineering is contact problems. In recent years, researchers have turned to alternative methods that can offer effective solutions in a shorter time, instead of solutions containing complex and long mathematical expressions. This study focuses on the estimation of the contact lengths in a homogeneous elastic layer suppressed by two elastic punches with two solution methods. Firstly, a new model was designed for estimation using Deep Learning Neural Network (DNN), one of the deep learning structures. Estimation of contact lengths was provided with the output of the DNN model, which was fed with the homogeneous elastic layer, the ratio of shear modules of the punches and the input parameters of punch radii. The finite element method was used as the second solution method. The problem was modelled in the ANSYS programme, and the solution was made with the same parameters used in DNN modelled. The results obtained from both solutions were compared with the solutions obtained by the theory of elasticity and classical NN in the literature. It had been seen that the results obtained with DNN and ANSYS were compatible with the results obtained with analytical and classical NN and the margin of error was smaller.
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İncele - MakaleAçık Erişim2023Scopus SJRQ2Stress analysis of the contact problem in a functionally graded layer loaded with a distributed load and two rigid circular punches resting on an elastic two quarter planes
Kaya, Fatih; Polat, Alper
In this study, the solution of the contact problem in a functionally graded (FG) layer resting on elastic two quarter planes was done using the finite element method (FEM). The contact problem consists of two rigid circular punches loaded FG and two elastic quarter planes. P and Q loads are transmitted to the FG layer by two rigid circular punches. All surfaces in the problem were considered as frictionless and the weight effect is also taken into account. The two-dimensional model of the contact problem was created with the ANSYS package program based on FEM and the stress analyzes were performed. All operations of quarter planes and circular punches are done with standard ANSYS menus. However, defining the material properties of the FG layer and dividing into meshes in finite elements cannot be done with standard menus. For this reason, a special macro was added to the program in order to define the material properties of the FG layer and to perform the mesh division, and the necessary parameters were applied to the layer by this macro. In the study, the effects of external load, stiffness parameter (βh), density parameter (γh) and contact stresses of distributed load change, normal stresses, and stresses along the depth were investigated.
AtıfScopus6WoS6OpenAlex5İncele - MakaleYalnız künye2022Scopus SJRQ1Analysis of discontinuous contact problem in two functionally graded layers resting on a rigid plane by using finite element method
Polat, Alper; Kaya, Yusuf
In this study, the problem of discontinuous contact in two functionally graded (FG) layers resting on a rigid plane and loaded by two rigid blocks is solved by the finite element method (FEM). Separate analyzes are made for the cases where the top surfaces of the problem layers are metal, the bottom surfaces are ceramic and the top surfaces are ceramic and the bottom surfaces are metal. For the problem, it is accepted that all surfaces are frictionless. A two-dimensional FEM analysis of the problem is made by using a special macro added to the ANSYS package program The solution of this study, which has no analytical solution in the literature, is given with FEM. Analyzes are made by loading different Q and P loads on the blocks. The normal stress (sigma y) distributions at the interfaces of FG layers and between the substrate and the rigid plane interface are obtained. In addition, the starting and ending points of the separations between these surfaces are determined. The normal stresses (sigma x, sigma y) and shear stresses (tau xy) at the point of separation are obtained along the depth. The results obtained are shown in graphics and tables. With this method, effective results are obtained in a very short time. In addition, analytically complex and long problems can be solved with this method.
AtıfWoS23İncele - MakaleYalnız künye2021Scopus SJRQ2Examination of contact problem between functionally graded punch and functionally graded layer resting on elastic plane
Polat, Alper
In this study, continuous contact problem in the functionally graded (FG) layer loaded with a FG flat punch resting on the elastic semi-infinite plane was analyzed by the finite element method (FEM). It was assumed that the shear modulus and density of the layer and punch varied according to exponentially throughout their depth. FG layer's weight was included to the problem and additionally all surfaces were considered as frictionless. Analysis of FG materials was performed with a special macro which was added to the ANSYS program. Firstly, the shear modulus of the punch was considered to be very rigid and the results of initial separation load (λcr) and distance (xcr) were compared with the analytical solution. Afterwards, results obtained from the contact analysis made according to the inhomogeneity parameters (β, γ) between FG punch-FG layer which had been unprecedented in the literature were discussed. As a result, FG punch's stress values at the punch edges where stress accumulations occurred were found to be smaller than the rigid punch. The security of the structure, longer life of the material and ease of production are directly related to the reduction of the stress values. The results obtained in this study are important in this respect. Also this work is the first study that investigates the effect of FG punch on the FG layer.
AtıfScopus8WoS10OpenAlex2İncele - MakaleAçık Erişim2020Köprü Yapısından Piezoelektrik Tabanlı Enerji Hasadının Sayısal Modellemesi
Polat, Alper; Kouider, Bendine
Köprüler, dengesizlik ve titreşimlere neden olabilecek çeşitli harici yüklere maruz kalabilirler. İyi tarafından bakıldığında, bu tür titreşimler sınırsız bir enerji kaynağı olabilir ve köprüleri izlemek için kullanılan cihazlara güç sağlayabilirler. Mekanik titreşimler, genellikle piezoelektrik tabanlı enerji hasadı olarak bilinen bir işlem olan doğrudan piezoelektrik etkisinden yararlanılarak elektrik enerjisine dönüştürülür. Bu çalışmada bir köprüdeki piezoelektrik enerji kazanımı incelendi. Piezoelektrik enerji toplayıcıları yerleştirilen köprünün bir modeli ANSYS APDL kullanılarak oluşturuldu. Zaman ve frekans bölgelerinde farklı hareketli yüklere sahip çeşitli senaryolar incelendi. Ayrıca, toplayıcıların pozisyonlarının etkisi de araştırıldı. Elde edilen sonuçlar, köprü sistemlerinden titreşim enerjisinin toplanmasının umut verici bir enerji kaynağı olduğunu gösterdi. Ayrıca toplayıcıların maksimum mod şekil genliğine yakın yerleştirilmesi ve hareketli yüklerin doğal frekanslarının toplayıcıların doğal frekansına uyacak şekilde tasarlanması durumunda daha faydalı olabileceğini gösterdi.
AtıfOpenAlex7TR Dizin1İncele - MakaleYalnız künye2020Scopus SJRQ2Analytical and finite element solutions of continuous contact problem in functionally graded layer
Kaya, Yusuf; Polat, Alper; Özşahin, Talat Şükrü
In this study, we solve the continuous contact problem of two layers with different material properties, loaded with two rigid flat blocks and resting on a rigid plane, by analytical and finite element methods. All surfaces are assumed to be frictionless. The upper layer is the functionally graded layer (FG), the height h1, the underlying layer is homogeneous, and the height is h2. It is assumed that the FG layer is isotropic and that the shear modulus and density change exponentially. The FG layer is loaded by means of two rigid flat blocks whose external loads are Q and P (per unit thickness in z direction). In the analytical solution of the problem, stress and displacement expressions are substituted in the boundary conditions and the problem is demoted to singular integral equations where the contact stresses are the unknown functions. These singular integral equations are solved numerically using the Gauss–Chebyshev integration formulas. Two-dimensional finite element analysis of the problem is performed using the ANSYS package program. The analyses are performed for different shear modulus ratios (μ2/μ-h1), distances between the blocks ((c − b)/h1) and inhomogeneity parameters (βh1). The contact stresses under the blocks, the normal stresses (σy) between interfaces of the FG layer and the homogeneous layer and between the homogeneous layer and rigid plane are also measured. In addition, the initial separation load and the initial separation distances (χcr, λcr) of the FG layer and homogeneous layer are determined. The results are presented comparatively as graphs and tables.
AtıfScopus18WoS19OpenAlex14İncele - MakaleYayıncıda açık erişim2020Optimal position of piezoelectric actuators for active vibration reduction of beams
Kouider, Bendine; Polat, Alper
This paper investigates the optimal placement of piezoelectric actuators for the active vibration attenuation of beams. The governing equation of the beam is achieved by coupled first order shear deformation theory with two node element. The velocity feedback controller is designed and used to calculate the feedback gain and then apply to the beam. In order to search for the optimal placement of the piezoelectric actuators, a new optimization criterion is considered based on the use of genetic algorithm to reduce the displacement output of the beam. The proposed optimization technique has been tested for two boundary conditions configurations; clamped -free and clamped-clamped beam. Numerical examples have been provided to analyze the effectiveness of the proposed technic.
AtıfScopus22WoS19OpenAlex21İncele - MakaleAçık Erişim2019Investigation of the Frictionless Contact Problem in A Rigidly Supported Homogeneous Layer by Using FEM
Polat, Alper
In this study, the continuous contact problem of a homogeneous layer of constant thickness perfectly bonded to a rigidsupport on its bottom surface and loaded a rigid stamp is investigated using the finite element method (FEM). It isassumed that the all contact surfaces are frictionless. The homogenous layer is loaded by rigid circular stamp withexternal load P. Two-dimensional finite element analysis of the problem is performed using ANSYS software. Also,normal stresses and shear stresses are investigated along the depth of the layer for different shear modulus ratios.Besides, contact length and contact stress between rigid block and homogenous layer are determined. The obtainedresults are compared to analytical solution and they are shown in graphs and tables.
- MakaleYalnız künye2018Analysis of Frictionless Contact Problem for A Weighted Layer on An Elastic Half Plane Using FEM
Polat, Alper; Kaya, Yusuf; Özşahin, Talat Şükrü
In this study, a comparative analysis of the continuous contact problem of a homogeneous layer loaded by two rigid flat blocks and resting on elastic half plane is investigated using the finite element method (FEM). The results obtained from the elasticity solution are compared with FEM solutions. Also in this problem, it is assumed that the all surfaces are frictionless. Two dimensional finite element analysis of the problem is carried out using ANSYS Mechanical APDL. The analyzes are performed for different loading conditions of Q and P loads. Initial separation load and initial separation points (xcr, λcr) and normal stresses (σy) between the homogenous layer and the elastic half plane are determined. The obtained results are shown in graphs and tables.
AtıfTR Dizin3İncele - MakaleYalnız künye2018COMPARISON OF FEM SOLUTION WITH ANALYTICAL SOLUTION OF CONTINUOUS AND DISCONTINUOUS CONTACT PROBLEM
Kaya, Yusuf; Polat, Alper; Özsahin, Talat Sukru
The continuous and discontinuous contact problem of a homogeneous layer loaded with three rigid flat blocks and resting on the elastic semi-infinite plane was investigated in this study by using the finite element method (FEM). All surfaces are assumed to be frictionless. The homogenous layer was loaded by means of three rigid flat blocks whose external loads are Q and P (per unit thickness in z direction). Two dimensional finite element analysis of the problem was performed using ANSYS package program. Analyzes were performed for loading conditions which are Q=P, Q=2P, Q=4P, Q=8P and Q=10P, and different values of block widths, distances between blocks and shear modulus. The initial separation loads and initial separation distances (lambda(cr), chi(cr)) between the homogeneous layer and the elastic semi-infinite plane were determined for continuous contact condition. The length of the separation zone was obtained for discontinuous contact condition. In addition to these, normal stress distributions between the layer and the semi-infinite plane were determined for continuous and discontinuous contact conditions. As a result of the study, the analytical results, and the results of the finite element method were shown by comparing as graphs and tables.
AtıfWoS5İncele - MakaleYalnız künye2018Scopus SJRQ1Analytical solution to continuous contact problem for a functionally graded layer loaded through two dissimilar rigid punches
Polat, Alper; Kaya, Yusuf; Özşahin, Talat Şükrü
A continuous contact problem of functionally graded layer resting on an elastic semi-infinite plane, which is loaded with through two different blocks is addressed in this study. The elasticity theory and integral transformation techniques are used in solution of the problem. The problem is reduced to a system of singular integral equations, and solved numerically by the aid of appropriate Gauss–Chebyshev integration formula. It is assumed that the elastic semi-infinite homogeneous plane is isotropic and all surfaces are frictionless and continuous. The shear modulus and the mass density of the FG layer vary exponentially along the thickness direction.
AtıfScopus19WoS18OpenAlex15İncele