Browsing by Author "Akis, T"

Now showing 1 - 4 of 4

Citation - WoS: 15
Citation - Scopus: 17
Experimental and Analytical Investigation of the Mechanics of Crawl Stroke Swimming
(Pergamon-elsevier Science Ltd, 2004) Akis, T; Orcan, Y; Civil Engineering
A three dimensional analytical model for crawl stroke swimming is developed in which the swimmer is modeled as a body and two arms connected to the body at the shoulder joints. Each arm is assumed to consist of three segments. The numerical results obtained from the model are compared with the results of two sets of experiments performed. In the first series of experiments, the tether forces developed in crawl stroke swimming are measured and a linear correlation between the tether force and the stroke rate is obtained. In the second series of experiments, untethered crawl stroke swimming for different arm position angles is recorded. The results are presented in graphical forms and the effect of stroke rate on swimming velocity is discussed. (C) 2003 Elsevier Ltd. All rights reserved.
Citation - WoS: 23
Citation - Scopus: 29
On the Elastic-Plastic Deformation of a Rotating Disk Subjected To a Radial Temperature Gradient
(Marcel dekker inc, 2003) Eraslan, AN; Akis, T; Civil Engineering
Elastic-plastic stress distribution in a nonisothermal rotating annular disk is analyzed by the use of Tresca and von Mises criteria. An energy equation that accounts for the convective heat transfer with a variable heat transfer coefficient is modeled. For a given angular velocity, the steady temperature distribution in the disk is obtained by the analytical solution of the energy equation. Tresca yield criterion and its associated flow rule are used to obtain the analytical stress distributions for a linearly hardening material. A computational model is developed to analyze elastic-plastic deformations of the disk using von Mises yield criterion and its flow rule. This model incorporates Swift's hardening law to simulate linear as well as nonlinear hardening material behavior. It is shown that the stress distribution in the disk is affected significantly by the presence of the temperature gradient.
Citation - WoS: 92
Citation - Scopus: 99
On the Plane Strain and Plane Stress Solutions of Functionally Graded Rotating Solid Shaft and Solid Disk Problems
(Springer Wien, 2006) Eraslan, AN; Akış, Tolga; Akis, T; Akış, Tolga; Civil Engineering; Civil Engineering
Closed form solutions to functionally graded rotating solid shaft and rotating solid disk problems are obtained under generalized plane strain and plane stress assumptions, respectively. The nonhomogeneity in the material arises from the fact that the modulus of elasticity of the material varies radially according to two different continuously nonlinear forms: exponential and parabolic. Both forms contain two material parameters and lead to finite values of the modulus of elasticity at the center. Analytical expressions for the stresses at the center are determined. These limiting expressions indicate that at the center of shaft/disk: (i) the stresses are finite, (ii) the radial and the circumferential stress components are equal, and (iii) the values of the stresses are independent of the variation of the modulus of elasticity. It is also shown mathematically that the nonhomogeneous solutions presented here reduce to those of homogeneous ones by an appropriate choice of the material parameters describing the variation of the modulus of elasticity.
Citation - WoS: 14
Citation - Scopus: 15
Yielding of Two-Layer Shrink-Fitted Composite Tubes Subject To Radial Pressure
(Springer Heidelberg, 2005) Eraslan, AN; Akis, T; Civil Engineering
Yielding of two-layer shrink-fitted composite tubes with axially constrained ends subject to either internal or external pressure is investigated in detail. In the framework of small deformations, a state of plane strain and von Mises yield criterion, analytical expressions are obtained for critical values of the pressure leading to plastic flow. It is shown that, depending on material properties and tube dimensions, different modes of plastic deformation may occur. Yielding may commence at the inner tube or at the outer tube or simultaneously in both tubes. The conditions for different nature of plastic flow are determined. Using analytical expressions obtained for critical values of the parameters and properties of real engineering materials, various numerical examples are handled and the variation of elastic limit pressure with interference and interface radius is explained.