Öner, Erdal; Al-Qado, Ahmed Wasfi Hasan

Contact mechanics is a complex and advanced field of engineering, with continuous research dedicated to modeling and examining contact problems in multilayered and multibody systems. Given that fatigue and fracture failures often result from contact loads, precise determination of subsurface stresses is crucial for the design of mechanical components. This study provides an exact analytical solution for the frictionless indentation of a functionally graded (FG) orthotropic layer by a rigid cylindrical punch. The FG orthotropic layer, which rests on a rigid, non-adhesive substrate, is treated as a nonhomogeneous medium with an orthotropic stress–strain relationship. Part of its top surface experiences normal tractions, while the rest remains traction-free. The analysis also incorporates the gravitational force affecting the FG orthotropic layer. Five distinct real orthotropic materials are used, each with individually graded stiffness constants in their principal directions, to define the FG orthotropic behavior of the material. The governing equations are formulated using the singular integral equation method and transformed into algebraic systems via the Gauss–Chebyshev integration technique. A comprehensive parametric study examines how variations in dimensionless punch radius, compressive force, inhomogeneity parameters, and body force influence contact widths, contact pressures, normal and shear stresses, critical load factor, and the initial point of interface separation.

AtıfScopus9·WoS9

İncele

Ahmed Wasfı Hasan Al-qado

Bu çalışmada, sürtünme etkileri ihmal edilerek, rijit temele oturan fonksiyonel derecelendirilmiş (FD) ortotrop bir tabakanın sürekli temas problemi incelenmiştir. FD ortotrop tabakaya, üst yüzeyinden rijit bir panç aracılığıyla iletilen tekil bir yük uygulanmıştır. Çözümlerde, FD ortotrop tabakanın ağırlık etkileri de hesaba katılmıştır. Ortotropik malzeme parametrelerinin ve yoğunluğun tabaka yüksekliği doğrultusunda üstel olarak değiştiği varsayılmıştır. Problemin çözümünde, gerilme ve yer değiştirme ifadeleri elastisite teorisi ve integral dönüşüm tekniklerinden faydalanılarak türetilmiştir. Problemin sınır şartları kullanılarak bir singüler integral denklem elde edilmiştir. Gauss-Chebyshev integrasyon yöntemi yardımıyla, silindirik ve düz panç profilleri için integral denklem nümerik olarak çözülmüştür. Çalışma sonucunda panç altındaki temas gerilmeleri, temas uzunlukları, FD ortotrop tabaka ve rijit temel arasında ilk ayrılmayı meydana getiren kritik ayrılma yükü ve ilk ayrılmanın meydana geleceği kritik ayrılma noktası, FD ortotrop tabakada simetri ekseni boyunca oluşan normal gerilmeler ve simetri ekseni yakınında seçilen bir kesit boyunca oluşan kayma gerilmeleri, FD ortotrop tabakanın alt yüzeyinde x ekseni boyunca oluşan normal gerilmeler çeşitli parametrelere ve farklı ortotrop malzeme türlerine bağlı olarak boyutsuz şekilde elde edilmiştir.

Öner, Erdal; Al-Qado, Ahmed Wasfi Hasan

Contact problems involving deformable bodies are widespread in both industrial and everyday situations. They have a crucial impact on structural and mechanical systems, which has led to significant efforts in modeling and numerical simulations. These efforts aim to improve understanding and optimization in various engineering applications. This study examines the contact problem involving a functionally graded (FG) orthotropic layer resting on a rigid foundation, without considering frictional influences. A point load is applied to the layer through a rigid punch on its top surface. Additionally, the gravitational effects of the FG orthotropic layer are considered in the analyses. Material parameters and density of the FG orthotropic layer are presumed to exhibit exponential variations along the vertical axis. The resolution of the problem involves deriving stress and displacement expressions through the application of elasticity theory and integral transformation techniques. By imposing the pertinent boundary conditions onto these expressions, a singular integral equation is formulated, wherein the contact stress under the punch remains unknown. Employing the Gauss–Chebyshev integration method, this integral equation is subsequently numerically solved, particularly for a flat punch profile. The outcomes of this investigation encompass the determination of contact stresses under the punch, the critical separation load, and the critical separation point—marking the initial separation between the FG orthotropic layer and the rigid foundation. Additionally, the analysis yields dimensionless representations of normal stresses along the symmetry axis within the FG orthotropic layer, as well as shear stresses along a designated section proximate to the symmetry axis. Furthermore, it provides insights into the normal stresses along the x axis at the bottom surface of the FG orthotropic layer, contingent upon various parameters and distinct orthotropic material compositions.

AtıfScopus12·WoS12·OpenAlex12

İncele