Cihan Demir

Yıldız Technical University · Department of Mechanical Engineering

The use of smart materials and passive controllers in modern technologies has stimulated the study of vibration in elastic systems with viscoelastic damping. It is also possible to create components with precise material distribution coefficients and distinct properties, such as Functionally Graded Materials. This work investigates the resonant fre...

The demand for increased reliability in automotive connector pin-end positions, which are press-fit to printed circuit boards, crucial for self-driving and driver assistance functionalities, has led to progressively tighter tolerance zones. Traditional manufacturing methods, such as cutting, bending and plastic injection, inherit limitations in ach...

Yük dağılımı, sistem elemanlarının deformasyonları nedeniyle alın genişliği boyunca temas sürekliliğinin bozulmasından etkilenir. Bu çalışmada, sistem deformasyon bileşenleri ile diş yükü dağılımı sürekliliğini göstermek için bir düz dişli çifti için birleştirilmiş bir yığın parametre modeli incelenmiştir. Yüklü bir diş teması analizi, yinelemeli i...

The frequency parameters of an Axially Functionally Graded (AFG) bar for viscoelastic and point mass boundary conditions are studied in this paper. The structures with functionally graded materials under axial loads can be modelled as AFG bars. Those may be considered as support elements with spring and dashpot in the vibration isolation. Keeping t...

This study consists of constructing and analyzing gear mathematical models of torque split systems for contact pressure distribution and dynamic transmission error at different gear positions concerning phase angles. According to the method specified in the AGMA 927 standard, load distribution is calculated by considering shaft torsion and bending...

The study aimed to evaluate the effects of fibers insertion and restorative material type on the stress distribution in endocrowns with finite element analysis. Five 3D models of first mandibular molars were created and restored as follows: (1) IN: intact tooth, (2) IPS-E: tooth restored with lithium disilicat ceramic endocrowns, (3) C-E: tooth res...

PURPOSE OF THE STUDY In this study, our aim is to examine the effect of proximal fibular osteotomy on knee and ankle kinematics with finite element analysis method. MATERIAL AND METHODS One 62-year-old, female volunteer's radiologic images were used for creating lower limb model. Osteotomized model (OM) which was created according to definition of...

It is a fact that specifying numerically the natural frequencies of a marine propeller rotating in a water environment is quite difficult due to the problem that arises from the inability to consider the effect of rotation and pressure distribution in the modal acoustic module of the software. In the present study, an alternative approach to the ex...

The harmonic response and resonance frequency behavior of the spring supported FGM beam against the lateral motion for the various values of support stiffness at the ends are analyzed by using the force transmissibility parameter with the finite-element method and Lagrange's equations. The steady-state responses to a sinusoidal varying force are de...

In most city water distribution systems, a considerable amount of water is lost because of leaks occurring in pipes. Moreover, an unobservable fluid leakage fault that may occur in a hazardous industrial system, such as nuclear power plant cooling process or chemical waste disposal, can cause both environmental and economical disasters. This situat...

Bu çalışmada, mobilya sektöründe sıklıkla kullanılan menteşe çeşitlerinden düz frenli tas menteşelerin kinematik, statik ve yorulma analizleri yapılmıştır. Bu kapsamda menteşenin katı modellenmesi paket program kullanılarak yapılmıştır. Menteşe kinetik ve kinematik analizi, çok parçalı gövde analizi programı ile yapılmıştır. Bu analizden elde edile...

Z Bu çalışmada farklı çaplara sahip farklı tiplerdeki tek helis açısına sahip ön gerilmeli monotron halatların doğal frekans analizi teorik ve deneysel olarak yapılmıştır. Teorik analizde daha önce çıkartılmış analitik formüllerden yararlanılmıştır. Bununla birlikte halat katı modeli oluşturularak sonlu elemanlar yöntemi ile doğal frekans analizi y...

This study examines the seismic behavior of the minaret of the well-known historical structure “Sultan Ahmed Mosque” under strong earthquake motion. Despite their slenderness and height, minarets are towers with well-established earthquake resistance. In general, these structures were constructed adjacent to the main structure and/or its components...

The paper deals with the seismic behavior of a masonry memorial which experienced two earthquakes in one year and suffered serious structural damage. The memorial was first built in 1992 to commemorate the soldiers died in great Gallipoli war, which was held between Ottoman Empire and Allied countries in Çanakkale peninsula a hundred years ago. In...

The paper deals with the seismic behavior and retrofitting of a historical masonry building called Treasury Building of Hagia Sophia (Skeuophylakion: a building where eucharistic elements were collected and prepared for services) which has experienced lots of earthquakes since it was constructed in 361 and suffered structural damage since then. A d...

In this study, the resonance frequency behavior of a functionally graded beam under viscoelastic boundary conditions is investigated. Nondimensional frequency parameters of the beam are analyzed using the finite element method. The system of equations of motion is derived by using Lagrange’s equations under the assumption of Euler–Bernoulli beam th...

Object: The center (axis) of rotation (COR) in the lumbar spine has been studied well. However, there is limited information on the kinetic and kinematic consequences of imposed shift in the location of the COR, although this type of shift can be seen after surgeries using motion preservation or dynamic stabilization devices. The objective of this...

Object: The goal of this study was to investigate the effect of ligament failure on the instantaneous center of rotation (ICR) in the lower lumbar spine. Methods: A 3D finite element model of the L4-5 segment was obtained and validated. Ligament failure was simulated by reducing ligaments in a stepwise manner from posterior to anterior. A pure b...

The dynamic behavior of plates with mixed boundary conditions has been the subject of intensive study for many years due to its great importance in many engineering applications. On-trend approach in dynamic response analysis is to combine mathematical model, test results and computer simulation. Classical techniques of mathematical modeling of int...

In this study, free vibration analysis of a functionally graded (FG) beam under various boundary conditions is carried out. Natural frequencies of the FG beam are analysed by using Finite Elements method. The system of equations of motion is derived by using Lagrange's equations with the assumption of Euler-Bernoulli beam theory. The material prope...

The fundamental frequencies of plate are important for engineering designs. Free vibration characteristics of isotropic rectangular plates with point, spring and viscoelastic supports have been studied by several researchers. However, the practical implementation of these boundary conditions in application is not at all trivial. In this study, the...

The vibration of orthotropic rectangular plates having viscoelastic point supports symmetrically located on its diagonals is analyzed. The plate is under the effect of a sinusoidally varying force at its center. The Lagrange equations are used in the solution process. To apply the Lagrange equations, the trial function denoting the deflection of th...

Vibration of orthotropic rectangular plates having viscoelastic point supports at the corners with symmetrically added four concentrated masses rigidly mounted on the two diagonals of the plate is analyzed. The Lagrange equations are used to examine the steady state response to a sinusoidally varying force applied at the centre of a viscoelasticall...

Vibration of orthotropic rectangular plates having viscoelastic point supports at the corners under the effect of sinusoidally varying concentrated moment is analyzed. The Lagrange equation is used to examine the free vibration characteristics and the steady state response to a sinusoidally varying concentrated moment acting at the centre of a visc...

Calculation of resonance frequencies of a six-wheeled vehicle has been propesed in this work by means of computational and experimental methods. In modelling vehicle, elastic body and rigid body techniques were used in computational methods. Therefore a three – dimensional finite element model was generated using beam elements and shell elements. T...