Wyniki wyszukiwania - BazTech

1

Solution of the plane contact problem between a finite-thickness laterally graded solid and a rigid stamp of an arbitrary tip-profile

Arslan O.

Archives of Mechanics

|

2019

|

Vol. 71, nr 6

531--565

EN

A singular integral equation (SIE) approach and a finite element method are developed for the solution of the frictional sliding contact problem between a finite-thickness laterally graded solid and a rigid stamp of an arbitrary tip-shape considering the plane strain assumption. An exponential shear modulus variation is introduced through the lateral direction. The field variables are obtained applying the Fourier transformation techniques on the governing partial differential equations. A surface displacement gradient is then utilized to derive a SIE of the second kind. A numerical solution of the SIE is performed by using a collation method and the Gauss quadrature integration techniques for the flat, triangular and circular stamp profiles. Finite element analyses (FEA) of the same contact problems are also performed upon selection of the augmented Lagrange contact-solver in ANSYS. For the incomplete (triangular and circular) stamp problems, an iterative algorithm is developed in order to obtain practically computational solutions for any desired contact lengths. Successful convergence of the SIE results and excellent consistency between the SIE and FEA results are attained, that indicate the reliability of both methods. The change in the thickness is shown to alter the contact behavior of the laterally graded solid significantly.

2

Inclined surface cracks in a graded half-plane subjected to frictional sliding contact

Arslan O.

Journal of Theoretical and Applied Mechanics

|

2018

|

Vol. 56 nr 4

915—925

EN

Fracture parameters of an inclined surface crack in a graded half-plane subjected to sliding frictional contact are investigated in this study. The problem is modelled via the finite element method (FEM) under the plane strain assumption employing a newly developed displacement boundary condition. The shear modulus of the half-plane is graded exponentially through the thickness direction by means of the homogeneous finite element approach. The augmented Lagrange algorithm is selected as an iterative contact solver. The mixed mode stress intensity factors (SIFs) which are induced by the contact stresses are evaluated utilizing the Displacement Correlation Technique (DCT). The accuracy of the present procedure is ensured comparing the SIF results to those calculated by an analytical method for vertical surface cracks. Additional SIF curves are generated as functions of the crack inclination in order to reveal the effects of non-homogeneity, punch location, crack length and friction coefficient. The prominent conclusion of this study indicates that the crack orientation has profound effects on the behavior of SIF curves, which has not been presented in any study published so far. Hence, consideration of crack inclination is proved essential to successfully predict fracture behavior of a graded medium under frictional contact.

3

A New Tool for Evaluating and Training Of Chemical Tanker Crew: Seafarer Evaluation And Training Software: DEPEDES (SETS)

Arslan O., Gurel O., Kadioglu M.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2010

|

Vol. 4, no. 4

461--464

EN

Shipping industry is growing regularly and regulative bodies of the industry put more emphasis on safety and environmental management of ships and ship management companies. With regard to the short-age of human resource officers, which will be continued by following years according to latest surveys, ship-ping industry has hard times to employ qualified officers in their fleets. Especially for chemical tanker ships, it is needed more qualified seafarers regarding to the environmental and safety concern of public and industry. Therefore, training of seafarers has become more important then ever before. Training of seafarers in office environment before sea period is as important as training at training institutions and on-the-job training. Therefore, measuring of seafarers’ performance and planning of individual training programs for each seafarer has become more important than ever. In order to develop the quality of seafarer training and consequently maintaining safe and profitable shipping, the factors which are important for evaluating the chemical tanker crew are determined and clustered in hier-archical manner; the weighting of factors for each rank are observed by utilizing Analytic Hierarchy Process (AHP) Method; the trainings which should be given to seafarers related to scores of evaluation factors are determined then the Seafarer Evaluation and Training Software DEPEDES (SETS) is created by utilizing Visual Basic Software. In this study, the content of SETS software is evaluated with details. Consequently, the main aim of this study is to maintain safe chemical tanker shipping by utilizing SETS software.

4

Effects of fatigue on navigation officers and SWOT analyze for reducing fatigue related human errors on board

Arslan O., Er I. D.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2007

|

Vol. 1, no. 3

345--349

EN

Maritime industry is still a human-centered industry in spite of latest technologies which has developed for reducing marine accidents. Human based errors cause marine accidents more than equipment based problems. These accidents cause catastrophic consequences about human life and marine environment. Fatigue of navigation officers plays effective role on these human-based errors and marine accidents. Fatigue can be defined as temporary loss of strength and energy resulting from hard physical or mental work. There are several factors that effect navigation officer’s fatigue. Fatigue is associated with poor quality sleep, negative environmental factors, high job demands and high stress. In this study, relationship between fatigue of navigation officers and marine accidents examined; Factors which are affecting fatigue of navigation officers determined with SWOT (strength, weaknesses, opportunities and threats) analysis method. SWOT analysis is an established method for assisting the formulation of strategy. With this analysis, efforts were made to explore the ways and means of converting the possible threats into opportunities and changing the weaknesses into strengths. Consequently strategic action plans were developed for minimizing fatigue related human errors on-board.