Mehmet Ali GÜLER, Tunç APATAY, Müfit GÜLGEÇ, Serkan DAĞ

Fonksiyonel derecelendirilmiş kaplamalarda sürtünmeli rijit zımba etkisiyle oluşan yüzeyaltı temas gerilmeleri

Bu çalışmada, fonksiyonel derecelendirilmiş malzeme (FDM)’den yapılan bir kaplamada yüzey altında, temasyüzeyindeki düzgün profilli sürtünmeli rijit zımba etkisiyle oluşan, gerilme dağılımlarını hesaplamak için tekilintegral denklemlerine dayalı bir yöntem geliştirilmiştir. Düzlem elastisite durumu ele alınmış ve Poissonoranının, homojen gövde ve FDM kaplama için aynı olduğu kabul edilmiştir. Problem, bir tekil integraldenklemine indirgenmiş ve bu denklem bir açılım – sıralama tekniği kullanılarak sayısal olarak çözülmüştür.Tekil integral denkleminin çözümünde kullanılan seriler Jacobi polinomları kullanılarak ifade edilmiştir. Zımbagenişliği, zımba konumu, sürtünme katsayısı ve malzeme parametrelerinin, kaplama derinliği boyunca oluşangerilme dağılımlarına etkileri incelenmiştir.

Subsurface contact stresses in functionally graded coatings loaded by a frictional flat stamp

In this study, a method has been developed in order to calculate the subsurface contact stresses in a functionallygraded coating loaded by a frictional flat stamp on the contact surface. Plane elasticity is considered; Poisson’sratio is taken to be constant for the FGM coating and the substrate is taken to be homogeneous. The problem isreduced to a singular integral equation which is solved numerically by means of an expansion collocationtechnique. The series expansions utilized in the solution of the singular integral equation are expressed in termsof Jacobi polynomials. Effects of punch length, punch location, coefficient of friction and material properties onthe subsurface stresses are investigated.

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1. Suresh, S. ve Mortensen, A., Fundamentals of Functially Graded Materials: Processing and Thermomechanical behavior of Graded Metals and Metal-ceramic Composites, IOM Communications Ltd., London, 1998.
2. Suresh, S., Olsson, M., Padture, NP. ve Jitcharoen, J., “Engineering the Resistance to Sliding-Contact Damage Through Controlled Gradients in Elastic Properties at Contact Surfaces”, Acta Materialia, 47, 3915-3926, 1999.
3. Suresh, S., “Graded Materials For Resistance to Contact Deformation and Damage”, Science, 292, 2447-2451, 2001.
4. Giannakopoulos, A. ve Suresh, S., “Indentation of Solids With Gradients in Elastic Properties: Part I. Point Force Solution”, International Journal of Solids and Structures, 34, 19, 2357-2392, 1997a.
5. Giannakopoulos, A. ve Suresh, S., “Indentation of Solids With Gradients in Elastic Properties: Part II. Axisymetric Indenters”, International Journal of Solids and Structures, 34, 19, 2393-2428, 1997b.
6. Giannakopoulos, A. ve Pallot, P., “Two Dimensional Contact Analysis of Elastic Graded Materials”, Journal of Mech. Phys. Solids, 48, 1597-1631, 2000.
7. Dağ, S. ve Erdoğan, F., “Crack and Contact Problems in Functionally Graded Materials”, Ceramic Transactions, 114, 739-746, 2000.
8. Güler, M.A. ve Erdoğan, F., “Contact Mechanics of Graded Coatings”, International Journal of Solids and Structures, 41, 3865-3889, 2004.
9. Yang, J. ve Ke, L.L. “Two Dimensional Contact Problem for a Coating Graded Layer - Substrate Structure Under a Rigid Cylindrical Punch”, International Journal of Mechanical Sciences, 50, 985-994, 2008.
10. Muskhelishvili, NI., Singular Integral Equation, Leyden: Noordhoff, 1953.