The contact problem of the functionally graded layer resting on rigid foundation pressed via rigid punch

Murat Yaylacı,Merve Abanoz,Ecren Uzun Yaylacı,Hasan Ölmez,Dursun Murat Sekban,Ahmet Birinci 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.5

The solution of contact problems is extremely important as we encounter many situations involving such problems in our daily lives. One of the most important parameters effective in solving contact problems is the materials of the parts in contact. While it is relatively easy to solve the contact mechanics of the systems created with traditional materials with a homogeneous microstructure and mechanical distribution, it may be more difficult to solve the contact problem of new generation materials that do not show a homogeneous distribution. As a result of this situation, it is seen that studies on contact problems of materials that do not exhibit such a homogeneous internal structure and mechanical properties are extremely limited in the literature. In this context, in this study, analytical and numerical analyzes of a contact problem created using functionally graded materials were carried out and the results were evaluated mutually. It has been decided that the contact areas and contact pressures acquired from numerical method are reasonably appropriate with the results obtained from the analytical method.

The receding contact problem of two elastic layers supported by two elastic quarter planes

Murat Yaylacı,Ahmet Birinci 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.2

The receding contact problem for two elastic layers whose elastic constants and heights are different supported by two elastic quarter planes is considered. The lower layer is supported by two elastic quarter planes and the upper elastic layer is subjected to symmetrical distributed load whose heights are 2a on its top surface. It is assumed that the contact between all surfaces is frictionless and the effect of gravity force is neglected. The problem is formulated and solved by using Theory of Elasticity and Integral Transform Technique. The problem is reduced to a system of singular integral equations in which contact pressures are the unknown functions by using integral transform technique and boundary conditions of the problem. Stresses and displacements are expressed depending on the contact pressures using Fourier and Mellin formula technique. The singular integral equation is solved numerically by using Gauss-Jacobi integration formulation. Numerical results are obtained for various dimensionless quantities for the contact pressures and the contact areas are presented in graphics and tables.

Numerical analysis of the receding contact problem of two bonded layers resting on an elastic half plane

Murat Yaylacı,Cemalettin Terzi,Mehmet Avcar 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.72 No.6

The present study deals with the numerical analysis of the symmetric contact problem of two bonded layers resting on an elastic half plane compressed with a rigid punch. In this context, Finite Element Method (FEM) based software called ANSYS and ABAQUS are used. It is assumed that the elastic layers have different elastic constants and heights and the external load is applied to the upper elastic layer by means of a rigid stamp. The problem is solved under the assumptions that the contact between two elastic layers, and between the rigid stamp are frictionless, the effect of gravity force is neglected. To validate the constructed model and obtained results a comparison is performed with the analytical results in literature. The numerical results for normal stresses and shear stresses are obtained for various parameters of load, material and geometry and are tabulated and illustrated.

Analyzing the contact problem of a functionally graded layer resting on an elastic half plane with theory of elasticity, finite element method and multilayer perceptron

Murat Yaylacı,Müjgen Yaylı,Ecren Uzun Yaylacı,Hasan Ölmez,Ahmet Birinci 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.78 No.5

This paper presents a comparative study of analytical method, finite element method (FEM) and Multilayer Perceptron (MLP) for analysis of a contact problem. The problem consists of a functionally graded (FG) layer resting on a half plane and pressed with distributed load from the top. Firstly, analytical solution of the problem is obtained by using theory of elasticity and integral transform techniques. The problem is reduced a system of integral equation in which the contact pressure are unknown functions. The numerical solution of the integral equation was carried out with Gauss-Jacobi integration formulation. Secondly, finite element model of the problem is constituted using ANSYS software and the two-dimensional analysis of the problem is carried out. The results show that contact areas and the contact stresses obtained from FEM provide boundary conditions of the problem as well as analytical results. Thirdly, the contact problem has been extended based on the MLP. The MLP with three-layer was used to calculate the contact distances. Material properties and loading states were created by giving examples of different values were used at the training and test stages of MLP. Program code was rewritten in C++. As a result, average deviation values such as 0.375 and 1.465 was obtained for FEM and MLP respectively. The contact areas and contact stresses obtained from FEM and MLP are very close to results obtained from analytical method. Finally, this study provides evidence that there is a good agreement between three methods and the stiffness parameters has an important effect on the contact stresses and contact areas.

Solving the contact problem of functionally graded layers resting on a HP and pressed with a uniformly distributed load by analytical and numerical methods

Murat Yaylacı,Bahar Şengül Şabano,Mehmet Emin Özdemir,Ahmet Birinci 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.82 No.3

The aim of this study is to examine the frictionless double receding contact problem for two functionally graded (FG) layers pressed with a uniformly distributed load and resting on a homogeneous half plane (HP) using analytical and numerical methods. The FG layers are made of a non-homogeneous material with an isotropic stress-strain law with exponentially varying properties. It is assumed that the contact at the FG layers and FG layer-HP interface is frictionless. The body force of the FG layers and homogeneous HP are ignored in the study. Firstly, an analytical solution for the contact problem has been realized using the theory of elasticity and the Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using the ANSYS package program based on FEM. Numerical results for contact lengths and contact pressures between FG layers and FG layer-HP were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio, and the heights of the FG layers for both methods. The results obtained using FEM were compared with the results found using the analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.

Vibration and buckling analyses of FGM beam with edge crack: Finite element and multilayer perceptron methods

Murat Yaylacı,Ecren Uzun Yaylacı,Mehmet Emin Özdemir,Şevval Öztürk,Hasan Sesli 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.4

This study represents a numerical research in vibration and buckling of functionally graded material (FGM) beam comprising edge crack by using finite element method (FEM) and multilayer perceptron (MLP). It is assumed that the material properties change only according to the exponential distributions along the beam thickness. FEM and MLP solutions of the natural frequencies and critical buckling load are obtained of the cracked FGM beam for clamped–free (C-F), hinged–hinged (H-H), and clamped–clamped (C-C) boundary conditions. Numerical results are obtained to show the effects of crack location (c/L), material properties (E2/E1), slenderness ratio (L/h) and end supports on the bending vibration and buckling properties of cracked FGM beam. The FEM analysis used in this paper was verified with the literature, and the fundamental frequency ratio ( ̅) and critical buckling load ratio ( ̅̅̅̅) results obtained were compared with FEM and MLP. The results obtained are quite compatible with each other

The investigation crack problem through numerical analysis

Murat Yaylacı 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.6

This paper presents a comparative study of finite element method (FEM) and analytical method for the plane problem of a layered composite containing an internal perpendicular crack in literature. The layered composite consists of two elastic layers having different elastic constants and heights. External load is applied to the upper elastic layer by means o a rigid punch and the lower elastic layer rests on two simple supports. Numerical simulations are realized by the world wide code ANYS software. Two dimensional analysis of the problem is carried out and the results are verified by comparison with solutions reported in literature. Main goal of the numerical simulation is to investigate the normal stress <i>σ_x</i>(0, <i>y</i>), stress intensity factors at the crack factor and the crack opening displacements

Finite element modeling of contact between an elastic layer and two elastic quarter planes

Murat Yaylacı,Mehmet Avcar 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.2

In this study, a two dimensional model of receding contact problem has been analyzed using finite element method (FEM) based software ANSYS and ABAQUS. For this aim finite element modeling of elastic layer and two homogeneous, isotropic and symmetrical elastic quarter planes pressed by means of a rigid circular punch has been presented. Mass forces and friction are neglected in the solution. Since the problem is examined for the plane state, the thickness along the z-axis direction is taken as a unit. In order to check the accuracy of the present models, the obtained results are compared with the available results of the open literature as well as the results of two software are compared using Root Mean Square Error (RMSE) and good agreements are found. Numerical analyses are performed considering different values of the external load, rigid circular radius, quarter planes span length and material properties. The contact lengths and contact stresses of these values are examined, and their results are presented. Consequently, it is concluded that the considered non-dimensional quantities have noteworthy influence on the contact lengths and contact stress distributions, additionally if FEM analysis is used correctly, it can be an efficient alternative method to the analytical solutions that need time.

mplementation of finite element and artificial neural network methods to analyze the contact problem of a functionally graded layer containing crack

Murat Yaylacı,Ecren Uzun Yaylacı,Mehmet Emin Özdemir,Sevil Ay,Şevval Öztürk 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.4

In this study, a two-dimensional model of the contact problem has been examined using the finite element method (FEM) based software ANSYS and based on the multilayer perceptron (MLP), an artificial neural network (ANN). For this purpose, a functionally graded (FG) half-infinite layer (HIL) with a crack pressed by means of two rigid blocks has been solved using FEM. Mass forces and friction are neglected in the solution. Since the problem is analyzed for the plane state, the thickness along the z-axis direction is taken as a unit. To check the accuracy of the contact problem model the results are compared with a study in the literature. In addition, ANSYS and MLP results are compared using Root Mean Square Error (RMSE) and coefficient of determination (R2), and good agreement is found. Numerical solutions are made by considering different values of external load, the width of blocks, crack depth, and material properties. The stresses on the contact surfaces between the blocks and the FG HIL are examined for these values, and the results are presented. Consequently, it is concluded that the considered non-dimensional quantities have a noteworthy influence on the contact stress distributions, and also, FEM and ANN can be efficient alternative methods to time-consuming analytical solutions if used correctly.

Examination of analytical and finite element solutions regarding contact of a functionally graded layer

Murat Yaylacı,Gökhan Adıyaman,Erdal Öner,AhmetBirinci 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.3

In this study, the continuous and discontinuous contact problems of functionally graded (FG) layer resting on a rigid foundation were considered. The top of the FG layer was loaded by a distributed load. It was assumed that the shear modulus and the density of the layer varied according to exponential functions along the depth whereas the the Poisson ratio remained constant. The problem first was solved analytically and the results were verified with the ones obtained from finite element (FE) solution. In analytical solution, the stress and displacement components for FG layer were obtained by the help of Fourier integral transform. Critical load expression and integral equation for continuous and discontinuous contact, respectively, using corresponding boundary conditions in each case. The finite element solution of the problem was carried out using ANSYS software program. In continuous contact case, initial separation distance and contact stresses along the contact surface between the FG layer and the rigid foundation were examined. Separation distances and contact stresses were obtained in case of discontinuous contact. The effect of material properties and loading were investigated using both analytical and FE solutions. It was shown that obtained results were compatible with each other.