Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ1A comprehensive parametric study of contact behavior in functionally graded bilayer systems
Öner, Erdal; Artar, Pınar Tuğçe
An extensive body of research in contact mechanics has been conducted due to its broad relevance to numerous engineering systems of practical interest. The investigation of contact behavior in deformable bodies represents a major challenge in engineering, as it plays a crucial role in the performance of structural and mechanical systems. Due to its importance, the field has received considerable attention in the literature. The present study focuses on analyzing the contact problem of a two-layered system composed of a functionally graded orthotropic layer (FGOL) and a functionally graded isotropic layer (FGIL). The layered system is fully bonded to a rigid substrate (RS), and frictional effects are neglected. No bonding is assumed between the two layers. The system is subjected to loading through a flat-ended rigid indenter (FERI), and the body forces of both layers are incorporated into the formulation. In the solution of the contact problem, the condition of constant vertical displacement (and thus its zero derivative) under the FERI is defined as the boundary condition; it is subsequently reduced to a singular integral equation through the application of Fourier integral transform techniques. This integral equation is subsequently solved numerically by applying the Gauss–Chebyshev integration formula. A comprehensive parametric study is conducted with respect to different material configurations and various dimensionless parameters, providing detailed insight into the mechanical response of the functionally graded layered system.
- MakaleYalnız künye2026Scopus SJRQ2A Multi-perspective Exploration of Contact Behavior in Orthotropic Layer Resting on Isotropic Half-Plane
Terzi, Merve; Öner, Erdal; Uzun Yaylacı, Ecren; Oktay, Mine Gül; Yaylacı, Murat
Contact problems which concern the stress distribution resulting from the interaction between two elastic bodies have long been a focus of research. In the field of solid mechanics, they hold particular importance because loads are generally transmitted to deformable bodies through their points of contact. This study investigates the contact problem of a layered medium containing a homogeneous orthotropic layer and an isotropic half-plane using a multi-method approach. A rigid flat indenter is applied to the orthotropic layer with frictional effects neglected, while the influence of body forces in the orthotropic layer is taken into account. Key contact parameters such as the contact stress under the indenter, the initial separation load, and the point of initial separation are determined as part of the analysis. The study is structured into three main sections. In the first section, the problem is analytically examined based on classical elasticity theory. Within this framework, a singular integral equation governing the contact problem is derived and solved numerically. The second section presents a finite element analysis using ANSYS software to simulate the contact interaction and evaluate the stress distribution. In the third and final section, the problem is addressed through artificial neural network (ANN) techniques, offering a data-driven perspective. Ultimately, the results obtained from the analytical, numerical (FEM), and ANN-based methods are compared, showing excellent agreement across all approaches.
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İncele - MakaleYalnız künye2026Scopus SJRQ2Seismic performance of prestressed girder bridges considering soil-pile-structure interaction and isolation systems
Öner, Erdal; Aydoğan, Ayşe N.; Yurdakul, Muhammet; Ergün, Mustafa; Artar, Musa
This article presents a comprehensive numerical study to determine the seismic performance of the Kirazlıyalı Çenesuyu Bridge, currently in service in Kocaeli, Türkiye, under both seismically isolated and non-isolated conditions, considering different soil types. The study holds great importance due to Kocaeli’s status as one of Türkiye’s most developed industrial regions, its location in a high-seismic-risk area, and its complex geological structure. The Kirazlıyalı Çenesuyu Bridge is a structure consisting of simply supported prestressed girders, commonly used in highway transportation networks. Designed as a twin bridge, the structure is 134 meters in length and 20 meters in width. Currently, the bridge is not equipped with seismic isolators; instead, its superstructure rests on elastomeric bearings over abutments and piers. Within the scope of this study, the bridge was retrofitted with Single Curved Friction Pendulum (SCFP) seismic isolators. These SCFP isolators were specifically designed in accordance with the Turkey Building Earthquake Code (TBEC-2019) standards for two distinct soil classes: ZA (hard rock) and ZC (very dense sand and gravel). The soil-pile interaction was simulated using single-parameter Winkler spring models in both horizontal and vertical directions. The Finite Element Model (FEM) of the bridge was developed in SAP2000 software, and analyses were conducted on this platform. The seismic performance of the bridge was assessed through nonlinear dynamic time history analyses using real earthquake ground motion records from the Imperial Valley, Kocaeli, and Kahramanmaraş (Pazarcık) earthquakes under various scenarios. The seismic responses of the bridge were examined in terms of base shear forces, lateral displacements of the pile, shear forces at the pier, bending moments at the pier, deck accelerations, and the hysteresis curves of the isolator. The study results demonstrate significant improvements in the seismic behavior of the bridge when equipped with the seismic isolation system. Furthermore, these improvements are shown to be directly influenced by the interaction of the structure-pile-soil system, as well as the compatibility between the frequency characteristics of this system and the frequency content of the imposed earthquake. The numerical data supporting these results are presented in the relevant sections through tables and graphs.
AtıfScopus2WoS2İncele - MakaleAçık Erişim2026Scopus SJRQ2An analytical study of contact mechanics in layered orthotropic–isotropic media with functional grading
Öner, Erdal; Artar, Pınar Tuğçe
Contact mechanics has played a central role in engineering progressing from early practices in ancient civilizations to the pioneering experimental studies of early scientists and more recently to advanced computational approaches. In modern research, functionally graded materials have gained increasing attention as their continuously varying properties enable the tailoring of stress fields, improvement of resistance to thermal and mechanical loads, and enhancement of the performance and reliability of layered systems.This study addresses the continuous contact problem of a two-layered medium composed of a functionally graded orthotropic layer (FGOL) placed over a functionally graded isotropic layer (FGIL). A rigid cylindrical punch applies a static concentrated load on the FGOL, while the lower surface of the FGIL is bonded to a rigid foundation. The layers are assumed to be unbonded at their interface, and frictionless contact conditions are imposed. To capture the effect of anisotropy, actual orthotropic materials are employed in the FGOL. An exponential through-thickness variation is adopted for the FGOL stiffness coefficients and density, and for the FGIL shear modulus and density. Under plane strain conditions, the contact formulation is reduced to a singular integral equation by applying the relevant boundary conditions. The equation is solved numerically using Gauss–Chebyshev integration techniques. The results provide detailed evaluations of contact lengths, stress distributions, critical load factors, and initial separation points as functions of selected nondimensionalized parameters and different orthotropic material choices, thereby contributing to a deeper understanding of the mechanics of graded layered systems.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2025Scopus SJRQ2Semi-analytical analysis of orthotropic-isotropic contact in layered media with consideration of body forces
Öner, Erdal; Oktay, Mine Gül
Contact mechanics is a key field that involves theoretical, computational, and experimental methods essential for tribology and designing components across various industries. It plays a crucial role in solving boundary value problems in civil engineering, mechanical engineering, and medicine. This study investigates the continuous contact problem of an orthotropic layer positioned on an isotropic half-plane, utilizing a semi-analytical approach based on elasticity theory. The solution considers the body force generated within the orthotropic layer when subjected to frictionless loading by a rigid cylindrical punch. The research presents dimensionless results for key parameters, including contact length, contact stress, critical separation distance, and critical separation load, while examining the effects of different dimensionless variables and the characteristics of the orthotropic materials. The novelty of this study lies in its simultaneous analysis of isotropic and orthotropic material behavior in a contact mechanics problem, along with the incorporation of body forces—a combination that has not been previously explored for this specific geometry in the literature. The study offers a more comprehensive understanding of the contact mechanics involved by addressing the often-overlooked influence of body forces, which play a crucial role in stress distribution and material deformation, particularly in large-scale structures. This inclusion allows for more accurate predictions of material behavior in real-world engineering applications where gravitational loads are significant factors.
AtıfScopus4WoS4OpenAlex4İncele - MakaleAçık Erişim2025Scopus SJRQ2Contact mechanics of functionally graded orthotropic layer under normal traction and gravity: an analytical perspective
Öner, Erdal; Al-Qado, Ahmed Wasfi Hasan
Contact mechanics is a complex and advanced field of engineering, with continuous research dedicated to modeling and examining contact problems in multilayered and multibody systems. Given that fatigue and fracture failures often result from contact loads, precise determination of subsurface stresses is crucial for the design of mechanical components. This study provides an exact analytical solution for the frictionless indentation of a functionally graded (FG) orthotropic layer by a rigid cylindrical punch. The FG orthotropic layer, which rests on a rigid, non-adhesive substrate, is treated as a nonhomogeneous medium with an orthotropic stress–strain relationship. Part of its top surface experiences normal tractions, while the rest remains traction-free. The analysis also incorporates the gravitational force affecting the FG orthotropic layer. Five distinct real orthotropic materials are used, each with individually graded stiffness constants in their principal directions, to define the FG orthotropic behavior of the material. The governing equations are formulated using the singular integral equation method and transformed into algebraic systems via the Gauss–Chebyshev integration technique. A comprehensive parametric study examines how variations in dimensionless punch radius, compressive force, inhomogeneity parameters, and body force influence contact widths, contact pressures, normal and shear stresses, critical load factor, and the initial point of interface separation.
AtıfScopus9WoS9İncele - MakaleAçık Erişim2025Scopus SJRQ2Tri-method analysis of contact mechanics in orthotropic-isotropic materials
Öner, Erdal; Oktay, Mine Gül; Uzun Yaylacı, Ecren; Yaylacı, Murat; Mirzaloğlu, İrem
This study examines the contact mechanics of a homogeneous orthotropic layer resting on a homogeneous isotropic half-space without being bonded, subjected to loading by a rigid cylindrical punch. The effect of the orthotropic layer’s body force has been taken into account in the study. The study is conducted in three phases. In the first phase, the contact problem is analytically tackled using advanced methods such as elasticity theory, integral transform techniques, and Gauss–Chebyshev integration. The second phase utilizes finite element analysis through ANSYS software, accurately modeling the system. In the final phase, an artificial neural network is employed, allowing the system to learn and recognize intricate patterns in the data. The standout feature of this study is its thorough comparison of these three distinct methodologies, offering a comprehensive understanding of the contact mechanics between isotropic and orthotropic materials. The results reveal key insights into contact length, maximum contact stress, critical separation load, and separation distance, all as functions of critical dimensionless parameters. This study is significant in today’s advancing field of contact mechanics as it not only explores the combined impact of body forces and the interaction between orthotropic and isotropic materials but also uniquely compares the results using three distinct methods, offering comprehensive insights that address both theoretical and practical challenges.
AtıfScopus27WoS27OpenAlex22İncele - MakaleYalnız künye2024Scopus SJRQ2Analyzing of continuous and discontinuous contact problems of a functionally graded layer: theory of elasticity and finite element method
Yaylacı, Murat; Öner, Erdal; Adıyaman, Gökhan; Öztürk, Şevval; Uzun Yaylacı, Ecren; Birinci, Ahmet
Contact mechanics analysis is crucial because such problems often arise in engineering practice. When examining contact mechanics, the material property of the contacting components is a crucially significant aspect. It is more complex to solve the contact mechanics of systems that are composed of materials that do not have a homogenous structure compared to materials that have homogeneous qualities throughout. While many studies on contact problems with homogeneous materials exist, those involving non-homogeneous materials are scarce in the literature. As material technology improves fast, there will be a greater need to solve such problems. In this respect, analytical and finite element method (FEM) solutions of the continuous and discontinuous contact problems of a functionally graded (FG) layer are carried out in this article. The FG layer in the problem rests on a rigid foundation and is pressed with a rigid punch. From the solutions, the contact length, contact stress, initial separation distance, and beginning and ending points of separation were determined, and the results were compared. It has been concluded that the FEM findings are consistent with the analytical results to a satisfactory degree. This study analyzes contact problem using different approaches and accounts for the influence of body force in a contact geometry that has yet to be reported.
AtıfScopus79WoS83OpenAlex68İncele - MakaleAçık Erişim2024Scopus SJRQ1Analytical approach to contact mechanics of functionally graded orthotropic layers with gravitational considerations
Öner, Erdal; Al-Qado, Ahmed Wasfi Hasan
Contact problems involving deformable bodies are widespread in both industrial and everyday situations. They have a crucial impact on structural and mechanical systems, which has led to significant efforts in modeling and numerical simulations. These efforts aim to improve understanding and optimization in various engineering applications. This study examines the contact problem involving a functionally graded (FG) orthotropic layer resting on a rigid foundation, without considering frictional influences. A point load is applied to the layer through a rigid punch on its top surface. Additionally, the gravitational effects of the FG orthotropic layer are considered in the analyses. Material parameters and density of the FG orthotropic layer are presumed to exhibit exponential variations along the vertical axis. The resolution of the problem involves deriving stress and displacement expressions through the application of elasticity theory and integral transformation techniques. By imposing the pertinent boundary conditions onto these expressions, a singular integral equation is formulated, wherein the contact stress under the punch remains unknown. Employing the Gauss–Chebyshev integration method, this integral equation is subsequently numerically solved, particularly for a flat punch profile. The outcomes of this investigation encompass the determination of contact stresses under the punch, the critical separation load, and the critical separation point—marking the initial separation between the FG orthotropic layer and the rigid foundation. Additionally, the analysis yields dimensionless representations of normal stresses along the symmetry axis within the FG orthotropic layer, as well as shear stresses along a designated section proximate to the symmetry axis. Furthermore, it provides insights into the normal stresses along the x axis at the bottom surface of the FG orthotropic layer, contingent upon various parameters and distinct orthotropic material compositions.
AtıfScopus12WoS12OpenAlex12İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Multi-method examination of contact mechanics in orthotropic layers under gravity
Öner, Erdal; Uzun Yaylacı, Ecren; Yaylacı, Murat
Analyzing the behavior of intelligent unconventional materials under diverse contact scenarios, in comparison to conventional materials, is a critical step in the initial design of engineering systems. This paper presents the development of analytical and numerical approaches for analyzing contact mechanics in a system comprising an orthotropic layer resting on a rigid foundation. Parametric analyses include the consideration of cylindrical and flat punch profiles. Analytical formulation utilizes integral transform methods to convert planar elasticity equations into a Cauchy-type singular integral equation of the second kind. A detailed description of the solution technique for the integral equation is provided, encompassing both the analytical formulation and the required discretization for obtaining the solution. Subsequently, a finite element approach (FEA) is employed to approximate contact bodies using a collection of finite elements, while contact boundaries are approximated by utilizing a set of polygons. Alternatively, the problem is addressed using the Multilayer Perceptron approach, a form of artificial neural network frequently applied in diverse machine learning applications, including scenarios involving contact problems. Finally, the resolution to the problem is achieved by employing the multilayer perceptron (MLP) method. The study yields determinations of contact stresses under the punch, the critical separation load resulting in the detachment of the orthotropic layer from the rigid foundation, and the corresponding separation distance. This analysis considers a range of dimensionless parameters and explored the behavior of diverse orthotropic materials. Comparisons between the results of the analytical method and computations from FEA and MLP reveal the exceptional accuracy attained by all three approaches. As the pioneer study employing three distinct approaches to examine continuous contact mechanics within an orthotropic layer under the influence of gravity, this research constitutes a valuable point of reference for upcoming scholars in the field.
AtıfScopus50WoS53OpenAlex44İncele - MakaleAçık Erişim2023Ortotrop Tabaka ile İzotrop Yarım Düzlem Arasındaki Sürekli Temas Probleminin Analitik Olarak İncelenmesi
Öner, Erdal; Oktay, Mine Gül
Hesaplamalı temas mekaniği, makine ve inşaat mühendisliği gibi alanların yanı sıra tıbbi uygulamalarda da büyük önem taşımaktadır. Mekaniğin bu dalı, iki cismin etkileşimine yanıt olarak temas alanı, basınç, deformasyon ve gerilmelere sayısal çözümler arar. Temas mekaniği konusu, son yıllarda mekanik ve uygulamalı matematik bilimlerinde yeni ve ilginç alanların gelişmesine önemli derecede katkı sağlamıştır. Bu çalışmada izotrop yarım düzlem üzerine oturan ortotrop tabakanın sürekli temasına ilişkin problem analitik yöntemle incelenmiştir. Çözümde sadece ortotrop tabakanın kütle kuvveti hesaba katılmıştır. Ortotrop tabaka rijit düz profile sahip bir panç vasıtasıyla yüklenmiştir. Tüm yüzeylerin sürtünmesiz olduğu varsayılmıştır. Ortotrop tabaka ve izotrop yarım düzlem için yer değiştirme ve gerilme ifadelerinin elde edilmesinde elastisite teorisi ve integral dönüşüm tekniklerinden yararlanılmıştır. Çalışma sonucunda çeşitli boyutsuz parametrelere ve ortotrop malzeme türlerine bağlı olarak panç altındaki temas gerilmesi, ortotrop tabaka ile izotrop yarım düzlem arasında ilk ayrılmaya neden olan kritik ayrılma yükü ve kritik ayrılma uzaklığı boyutsuz olarak elde edilmiştir.
- MakaleAçık Erişim2023Scopus SJRQ3A STUDY ON THE CONTACT PROBLEM OF A LAYER CONSISTING OF FUNCTIONALLY GRADED MATERIAL (FGM) IN THE PRESENCE OF BODY FORCE
Adiyaman, Gökhan; Öner, Erdal; Yaylaci, Murat; Birinci, Ahmet
One of the most important components of the early design process for layered systems is gaining a knowledge of the behavior of materials under varied contact situations. Functionally graded materials (FGMs) have grown in popularity in layered systems as a result of their numerous benefits, such as permitting the reduction of local stress concentrations and thermal stresses often experienced in traditional composites. This paper suggests an analytical approach to solving the continuous and discontinuous contact problems of a functionally graded (FG) layer subjected to a distributed load. Elasticity theory and integral transform methods provide the basis of the aforementioned analytical approach. The FG layer rests on a half-plane that is homogeneous, and there is no adhesion or bonding at the contact surface. For this problem, we assume an exponentially varying shear modulus and mass density in the FG layer. In the solution, the body force of the FG layer is considered. The problem is solved analytically by applying boundary conditions for both continuous and discontinuous contact cases. The presented results show the effects of load factor, amplitude of distributed load, inhomogeneity parameters, and interface material property mismatch on contact stress distributions, initial separation load (critical load), initial separation distance, starting and end point of separation, and separation interval.
AtıfScopus39WoS40OpenAlex30İncele - MakaleAçık Erişim2022Scopus SJRQ2On the plane receding contact between two functionally graded layers using computational, finite element and artificial neural network methods
Öner, Erdal; Şengül Şabano, Bahar; Uzun Yaylacı, Ecren; Adıyaman, Gökhan; Yaylacı, Murat; Birinci, Ahmet
The frictionless double receding contact problem for two functionally graded (FG) layers pressed by a uniformly distributed load is addressed in this paper. The gradation in the layers is assumed to follow an exponential variation through the height with constant Poisson's ratios. The lower layer rests on a homogeneous half-plane (HP). There is no adhesion between the FG layers or between the lower layer and the HP. The body forces of the FG layers and HP are ignored. First, the governing equations are reduced to a system of two singular integral equations with contact pressures and contact lengths as unknowns using Fourier transform techniques and boundary conditions. The integral equations are solved numerically using the Gauss-Chebyshev integration formula. Then, a parametric finite element analysis is performed using the augmented contact method. Finally, the problem was extended based on the multilayer perceptron (MLP), an artificial neural network used for different problem parameters. The effects of stiffness parameters, the normalized load length, the ratio of shear moduli, the ratio of FG layer heights to the normalized contact lengths, and normalized maximum contact pressures are explored. The results of finite element analysis and the MLP approach are used to validate the normalized maximum contact pressures and contact lengths obtained from an analytical method based on elasticity theory, and finally, good agreement between these three methods results is obtained. The obtained results could help in designing multibody indentation systems with FGMs.
AtıfScopus85WoS84OpenAlex48İncele - MakaleYalnız künye2022Scopus SJRQ2Application of artificial neural networks in the analysis of the continuous contact problem
Yaylacı, Ecren Uzun; Öner, Erdal; Yaylacı, Murat; Özdemir, Mehmet Emin; Abushattal, Ahmad; Birinci, Ahmet
This paper investigates the artificial neural network (ANN) to predict the dimensionless parameters for contact pressures and contact lengths under the rigid punch, the initial separation loads, and the initial separation distances of a contact problem. The problem consisted of two elastic infinitely layers (EL) loaded by means of a rigid cylindrical punch and resting on a half-infinite plane (HP). Firstly, the problem was formulated and solved theoretically using the Theory of Elasticity (ET). Secondly, the contact problem was extended based on the ANN. External load, the radius of punch, layer heights, and material properties were created by giving examples of different values used at the training and test stages of ANN. Finally, the accuracy of the trained neural networks for the case was tested using 134 new data, generated via ET solutions to determine the best network model. ANN results were compared with ET results, and well agreements were achieved.
AtıfScopus62WoS60OpenAlex13İncele - MakaleAçık Erişim2021Computational contact mechanics for a medium consisting of\rfunctionally graded material coating and orthotropic substrate
Öner, Erdal
This paper presents a semi-analytical method to investigate the frictionless contact mechanics between a\rfunctionally graded material (FGM) coating and an orthotropic substrate when the system is indented by a\rrigid flat punch. From the bottom, the orthotropic substrate is completely bonded to the rigid foundation. The\rbody force of the orthotropic substrate is ignored in the solution, while the body force of the FGM coating is\rconsidered. An exponential function is used to define the smooth variation of the shear modulus and density\rof the FGM coating, and the variation of Poisson’s ratio is assumed to be negligible. The partial differential\requation system for the FGM coating and the orthotropic substrate is solved analytically through Fourier\rtransformations. After applying boundary and interface continuity conditions to the mixed boundary value\rproblem, the contact problem is reduced to a singular integral equation. The Gauss–Chebyshev integration\rmethod is then used to convert the singular integral equation into a system of linear equations, which are\rsolved using an appropriate iterative algorithm to calculate the contact stress under the rigid flat punch. The\rparametric analyses presented here demonstrate the effects of normalized punch length, material\rinhomogeneity, dimensionless press force, and orthotropic material type on contact stresses at interfaces,\rcritical load factor, and initial separation distance between FGM coating and orthotropic substrate. The\rdeveloped solution procedures are verified through the comparisons made to the results available in the\rliterature. The solution methodology and numerical results presented in this paper can provide some useful\rguidelines for improving the design of multibody indentation systems using FGMs and anisotropic materials.
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İncele - MakaleAçık Erişim2021Scopus SJRQ1Investigation of time-history response of a historical masonry minaret under seismic loads
Yurdakul, Muhammet; Yılmaz, Fatih; Artar, Musa; Can, Ömer; Öner, Erdal; Daloğlu, Ayşe T.
This study presents an investigation of the seismic performance of a historical masonry minaret which was built in the 12th century in Bayburt. The minaret was built as masonry with regional stones and handmade bricks. The most important feature of the minaret is its longitudinally conical geometry. An experimental investigation was made to obtain the mechanical properties of the regional stone used in the historical minaret. A three-dimensional Finite Element Model of the historical minaret was created in SAP2000. Three earthquake ground motions such as Erzincan, Kocaeli-Duzce, and Van-Ercis were used to investigate the seismic performance of the historical minaret. The results show that Erzincan, Kocaeli-Duzce and Van-Ercis earthquakes may cause some damages in the same zone of the minaret body since the tensile stresses occurred due to the earthquakes exceed the limit tensile stress of the masonry brick. The use of the data obtained from the experimental investigation of the Bayburt yellow stone in the analysis is important for the reliability of the results.
AtıfScopus44WoS43OpenAlex44İncele - MakaleYalnız künye2021Scopus SJRQ3Two-dimensional frictionless contact analysis of an orthotropic layer under gravity
Öner, Erdal
An analytical method for solving the two-dimensional frictionless continuous contact problem of an orthotropic layer pressed by a rigid stamp is presented in this paper. The orthotropic layer lies on a rigid foundation, and plane-strain orthotropy prevails in the layer, which is not bonded to the rigid foundation. An external load was applied to the orthotropic layer through a rigid stamp. The profiles of flat and cylindrical stamps as stamp shapes were handled separately. The orthotropic layer was assumed to be subjected to uniform vertical body forces owing to the effect of gravity. For values of the resultant compressive force P acting on the stamp vertically that were lesser than a critical value, the continuous contact along the orthotropic layer–rigid foundation interface was maintained. By assuming plane-strain conditions, the governing equations corresponding to the mentioned contact problem were extracted separately in the presence and absence of the body force of the orthotropic layer using the theory of elasticity and the Fourier integral transformation technique. Subsequently, the mixed boundary value problem was reduced to a singular integral equation, and the numerical solution of this singular integral equation was obtained by applying the Gauss–Chebyshev integration formulas. Numerical results reveal the effect of the orthotropic material parameters, stamp length (in the case of a flat stamp), stamp radius (in the case of a cylindrical stamp), applied load on the contact stress distributions, contact length, initial separation load and initial separation distance. The results of this study may provide insights for engineers in fields closely related to contact mechanics.
AtıfScopus29WoS29OpenAlex26İncele - MakaleYalnız künye2021Scopus SJRQ1Frictionless contact mechanics of an orthotropic coating/isotropic substrate system
Öner, Erdal
This study has been performed to investigate the receding contact problem of a homogeneous orthotropic coating that is not bonded to a homogeneous isotropic substrate without any interfacial defects. The isotropic substrate is supported on a Winkler foundation. The problem is solved assuming that the contact between the rigid punch and orthotropic coating, and that between the orthotropic coating and isotropic substrate, are frictionless. Additionally, the effect of the body forces is neglected, and only compressive normal tractions can be transmitted through the interfaces. The contact analysis of the orthotropic coating, which is subjected to a contact load using a rigid cylindrical punch, is performed under plane strain conditions. The governing equations are analytically found using the theory of elasticity and Fourier integral transformation techniques. Subsequently, the governing equations are reduced to a system of two singular equations, wherein the unknowns are the contact stresses and contact widths. To numerically solve the resulting singular integral equations, Gauss-Chebyshev integration formulas are employed. It is analyzed the influence of the following parameters on the contact stresses and contact widths: orthotropic-material properties, punch radius, load ratio, Winkler foundation stiffness.
AtıfScopus26WoS26OpenAlex10İncele - MakaleYalnız künye2021Scopus SJRQ1Investigation of continuous and discontinuous contact cases in the contact mechanics of graded materials using analytical method and FEM
Yaylacı, Murat; Adıyaman, Gökhan; Öner, Erdal; Birinci, Ahmet
The aim of this paper was to examine the continuous and discontinuous contact problems between the functionally graded (FG) layer pressed with a uniformly distributed load and homogeneous half plane using an analytical method and FEM. The FG layer is made of non-homogeneous material with an isotropic stress–strain law with exponentially varying properties. It is assumed that the contact at the FG layer-half plane interface is frictionless, and only the normal tractions can be transmitted along the contacted regions. The body force of the FG layer is considered in the study. The FG layer was positioned on the homogeneous half plane without any bonds. Thus, if the external load was smaller than a certain critical value, the contact between the FG layer and half plane would be continuous. However, when the external load exceeded the critical value, there was a separation between the FG layer and half plane on the finite region, as discontinuous contact. Therefore, there have been some steps taken in this study. Firstly, an analytical solution for continuous and discontinuous contact cases of the problem has been realized using the theory of elasticity and Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using ANSYS package program based on FEM. Numerical results for initial separation distance and contact stress distributions between the FG layer and homogeneous half plane for continuous contact case; the start and end points of separation and contact stress distributions between the FG layer and homogeneous half plane for discontinuous contact case were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio and load factor for both methods. The results obtained using FEM were compared with the results found using analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.
AtıfScopus78WoS78OpenAlex21İncele - MakaleYalnız künye2021Scopus SJRQ1Assessment of different solution methods for receding contact problems in functionally graded layered mediums
Yaylacı, Murat; Eyüboğlu, Ayşegül; Adıyaman, Gökhan; Yaylacı, Ecren Uzun; Öner, Erdal; Birinci, Ahmet
This paper presents a comparative study of different methods, such as the analytical method, finite element method (FEM), and multilayer perceptron (MLP) for analyzing a frictionless receding contact problem. The problem consists of two layers resting on a Winkler foundation. The top layer is functionally graded (FG) along the depth and pressed using a rigid cylindrical stamp, whereas the bottom layer is homogeneous. We assumed that the contact between the two layers, and that between the FG layer and the rigid cylindrical stamp are frictionless; additionally, compressive normal tractions can be transmitted through the interface. First, the problem was solved analytically using the theory of elasticity and integral transform techniques. Second, the finite element solution of the problem was obtained using ANSYS software. Finally, the problem was extended based on the MLP, which an artificial neural network used for different problem parameters. The results of this study showed that the variations in the contact lengths at the interface between the rigid cylindrical stamp and the FG layer, those between the homogeneous layer and the FG layer, and the maximum contact pressures at these interfaces depended on various dimensionless quantities such as the stamp radius, stiffness parameter, shear modulus ratio, and elastic spring constant ratio. We observed that the results obtained with the three different methods, namely the analytical method, FEM, and MLP, are extremely compatible with each other, thus proving the accuracy of these results.
AtıfScopus87WoS86OpenAlex40İncele