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.

AtıfScopus39·WoS40·OpenAlex30

İncele

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.

AtıfScopus29·WoS29·OpenAlex26

İncele

Öner, Erdal; Birinci, Ahmet

The continuous contact problem for two elastic layers resting on an elastic half-infinite plane and loaded by means of a rigid stamp is presented. The elastic layers have different heights and elastic constants. An external load is applied to the upper elastic layer by means of a rigid stamp. The problem is solved under the assumptions that all surfaces are frictionless, body forces of elastic layers are taken into account, and only compressive normal tractions can be transmitted through the interfaces. General expressions of stresses and displacements are obtained by using the fundamental equations of the theory of elasticity and the integral transform technique. Substituting the stress and the displacement expressions into the boundary conditions, the problem is reduced to a singular integral equation, in which the function of contact stresses under the rigid stamp is unknown. The integral equation is solved numerically by making use of the appropriate Gauss-Chebyshev integration formula for circular and rectangular stamp profiles. The contact stresses under the rigid stamp, contact areas, initial separation loads, and initial separation distances between the two elastic layers and the lower-layer elastic half-infinite plane are obtained numerically for various dimensionless quantities and shown in graphics and tables.

AtıfScopus24·WoS25·OpenAlex26

İncele

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.

AtıfScopus36·WoS37·OpenAlex25

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