Yazarlar
Yayınlar
- 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.
AtıfScopus85WoS84OpenAlex48
İncele - 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 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 - MakaleYalnız künye2018THE GENERAL SOLUTION OF A LAYERED MEDIUM RESTING ON A RIGID FOUNDATION
Adiyaman, Gokhan; Öner, Erdal; Birinci, Ahmet
In this study, the general solution of a receding contact problem of layered medium resting on rigid foundation is considered. The layered medium consists of N homogeneous layer with varying material properties and heights. The contact surfaces can be receding or attached. The problem may include M receding contact surfaces. The layered medium is loaded with n concentrated loads transmitted by circular stamps and r distributed loads. The problem is reduced to integral equation system using elasticity theory and Fourier integral transform. The numerical solution of the system is done by using Matlab. A program is written to solve the problem given by the user with any geometry and loading. The program is tested with two studies from the literature and it was shown that the results are compatible.
AtıfWoS3İncele - MakaleAçık Erişim2014Scopus SJRQ1Comparison between Analytical and ANSYS Calculations for a Receding Contact Problem
Yaylaci, Murat; Öner, Erdal; Birinci, Ahmet
This paper considers a receding contact problem for two elastic layers (with different elastic constants and heights) supported by two elastic quarter planes. The lower layer is supported by two elastic quarter planes, and the upper elastic layer is subjected to a symmetrical distributed load whose length is 2a on its top surface. It is assumed that contact between all surfaces is frictionless, and the effect of gravity force is neglected. First, the problem is formulated and solved using the theory of elasticity and integral transform technique. Using the integral transform technique and boundary conditions of the problem, the problem is reduced to a system of singular integral equations in which contact pressures and contact areas are unknown. The system of singular integral equations is solved numerically by using the Gauss-Jacobi integration formulation. Second, the receding contact problem has been developed based on the FEM ANSYS software. Two-dimensional analysis of the problem is carried out. The ANSYS and analytical results for the contact pressures, contact areas, and normal stresses (sigma(x) and sigma(y)) along the axis of symmetry are given for various dimensionless quantities. The ANSYS results are verified by comparison with analytical results. (C) 2014 American Society of Civil Engineers.
AtıfWoS50OpenAlex35İncele - MakaleAçık Erişim2014Scopus SJRQ2Solution of a receding contact problem using an analytical method and a finite element method
Öner, Erdal; Yaylaci, Murat; Birinci, Ahmet
In this study, a receding contact problem for two elastic layers supported by a Winkler foundation is handled using two different methods such as an analytical method and a finite element method. Firstly, the problem is solved analytically using linear elasticity theory. Then, in order to solve the same problem in a different way, a finite element model of the problem is created by ANSYS software, and finite element analysis of the problem is performed. The contact stresses and the contact areas at the interfaces between punch-Layer 2 and Layer 1-Layer 2 are obtained for both solutions, and it is shown that the finite element method indicates a good agreement with the analytical method.
AtıfScopus36WoS37OpenAlex25İncele