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• MakaleAçık Erişim2026Scopus SJRQ1/r/bayburt/11551
  A 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.

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• MakaleYalnız künye2026Scopus SJRQ2/r/bayburt/11480
  A 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.

  AtıfScopus15·WoS10·OpenAlex16

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• MakaleYalnız künye2026Scopus SJRQ2/r/bayburt/11269
  Seismic 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.

  AtıfScopus2·WoS2

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• MakaleAçık Erişim2026Scopus SJRQ2/r/bayburt/11253
  An 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.

  AtıfScopus1·WoS1·OpenAlex1

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• MakaleYalnız künye2025Scopus SJRQ2/r/bayburt/11498
  Semi-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.

  AtıfScopus4·WoS4·OpenAlex4

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11442
  Contact 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.

  AtıfScopus9·WoS9

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11383
  Tri-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.

  AtıfScopus27·WoS27·OpenAlex22

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• MakaleYalnız künye2024Scopus SJRQ2/r/bayburt/13143
  Analyzing 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.

  AtıfScopus79·WoS83·OpenAlex68

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• MakaleAçık Erişim2024Scopus SJRQ1/r/bayburt/12949
  Analytical 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.

  AtıfScopus12·WoS12·OpenAlex12

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• MakaleYayıncıda açık erişim2024Scopus SJRQ1/r/bayburt/11845
  Multi-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.

  AtıfScopus50·WoS53·OpenAlex44

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