Ph.D. Tezi Görüntüleme

Student: Pınar BORA
Supervisor: Prof. Dr. Talat Şükrü ÖZŞAHİN
Department: İnşaat Mühendisliği
Institution: Graduate School of Natural and Applied Sciences
University: Karadeniz Technical University Turkey
Title of the Thesis: THE CONTACT PROBLEM FOR TWO ELASTIC LAYERS LOADED BY MEANS OF TWO RIGID RECTANGLE BLOCKS AND RESTING ON AN ELASTIC HALF INFINITE PLANE
Level: Ph.D.
Acceptance Date: 30/6/2016
Number of Pages: 163
Registration Number: Di1147
Summary:

      In this study, the analytical solution is derived according to the theory of elasticity for the continuous and discontinuous contact problems in two homogeneous and isotropic layers with different thicknesses and elastic properties; the layers are underlain by an elastic semi-infinite plane and are loaded with two rectangular blocks. Analytical solution results are then compared with numerical solutions using ANSYS. The study consists of four chapters. Chapter I briefly reviews the historical development of contact problems and provides the general expressions for stresses and displacements of the two layers and the underlying plane using fundamental equations of elasticity and integral transform techniques. Chapter II provides the analytical solution derived for the continuous and discontinuous contact problems and provides the base for numerical computation in ANSYS. First, the continuous contact case is covered. Stress and displacement expressions are substituted into the boundary conditions, and the problem is reduced to singular integral equations, where the contact stresses are the unknown function. The solution of singular integral equations is obtained using Gauss- Chebyshev integration formulas. The load which causes the first separation and the point where the separation starts are obtained for the interfaces. Second, the discontinuous contact case is examined in two parts. First for the interface between the bottom layer and the semi-infinite plane, and then for the interface between the two layers. The same procedure as in continuous contact problem is followed for the discontinuous contact problem, except the number of singular integral equations become three with the third unknown being the slope at the separation region. By solving these three integral equations, one can easily obtain the separation between the interfaces, contact stresses under the blocks, and stress components at every point of interfaces. Then, this problem was adopted and computed in ANSYS using Finite Element Method. In Chapter III, stresses and displacements are obtained using various dimensionless quantities of block widths, distances between blocks, layer thicknesses, load rates (applied to different blocks), and material properties, and the results are documented in tables and figures. The final chapter includes the conclusions and recommendations.

      Key Words: Theory of Elasticity, Continuous Contact, Discontinuous Contact, Contact Stress, Initial Separation Load, Initial Separation Distance, Separation, İntegral Transforms Tecnique, Finit Element Method, ANSYS