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- 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 - Yüksek Lisans TeziAçık Erişim2023İzotrop yarım düzleme oturan ortotrop tabakanın sürekli temas problemi
Mine Gül Oktay
Temas mekaniği, güvenli ve enerji tasarruflu tasarımların inşası için vazgeçilmez olan mühendislik bilimlerinin temel disiplinlerindendir ve geniş teorik, sayısal ve deneysel araştırma alanını kapsamaktadır. Bu özelliğiyle mekaniğin önemli bir dalıdır ve halen de bu önemini sürdürmektedir. Temas mekaniği özellikle konvansiyonel olarak dökme malzemelerden imal edilen tribolojik ve yük aktarma düzeneklerinde öne çıkmaktadır. Mekanikte temas problemlerinin incelenmesini, varyasyonel eşitsizliklerin formülasyonu ve çözümü ile ilişkilendirmek mümkündür. Temas mekaniği konusu, son yıllarda mekanik ve uygulamalı matematik bilimlerinde yeni ve ilginç alanların gelişmesine önemli derecede katkı sağlamıştır. Debriyajlar, frenler, yol kaplamaları, lastikler, bilyalı rulmanlar, fren diskleri, menteşeler, demiryolu balastları, temeller gibi sayısız uygulama temas problemlerinin ilgi alanına girmektedir. Bu çalışmada izotrop yarım düzlem üzerine oturan ortotrop tabakanın sürekli temasına ilişkin problem incelenmiştir. Çözümde sadece ortotrop tabakanın kütle kuvveti hesaba katılmıştır. Ortotrop tabaka rijit bir panç vasıtasıyla yüklenmiştir. Tüm yüzeylerin sürtünmesiz olduğu varsayılmıştır. Çalışma sonucunda çeşitli boyutsuz parametrelere ve ortotrop malzeme türlerine bağlı olarak temas uzunluğu, temas gerilmesi, kritik ayrılma uzaklığı ve kritik ayrılma yükü 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 - 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