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Duzgun, Oguz Akin,Budak, Ahmet Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.40 No.6
This paper evaluates the effects of topographical and geotechnical irregularities on the dynamic response of the 2-D soil-structure systems under ground motion by coupling finite and infinite elements. A numerical procedure is employed, and a parametric study is carried out for single-faced slope topographies. It is concluded that topographic conditions may have important effects on the ground motion along the slope. The geotechnical properties of the soil will also have significantly amplified effects on the whole system motion, which cannot be neglected for design purposes. So, dynamic response of a soil-structure systems are primarily affected by surface shapes and geotechnical properties of the soil. Location of the structure is another parameter affecting the whole system response.
Investigation of thermo-structural behaviors of different ventilation applications on brake discs
Mesut Duzgun 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.1
One of the most common problems related to brake discs is overheating, which negatively affects braking performance especially under the continuous braking conditions of vehicles. Ventilation applications on brake discs can significantly improve the brake system performance by reducing the heating of the discs. In this study, the thermal behaviors of ventilated brake discs using three different configurations were investigated at continuous brake conditions in terms of heat generation and thermal stresses with finite element analysis. The results were compared with a solid disc. Heat generation on solid brake discs reduced to a maximum of 24% with ventilation applications. The experimental study indicated finite element temperature analysis results in the range between 1.13% and 10.87%. However,thermal stress formations were higher with ventilated brake discs in comparison to those with solid discs.
Ucar, Taner,Merter, Onur,Duzgun, Mustafa Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.6
The objective of this paper is to present an energy-based method for calculating target displacement of RC structures. The method, which uses the Newmark-Hall pseudo-velocity spectrum, is called the "Pseudo-velocity Spectrum (PSVS) Method". The method is based on the energy balance concept that uses the equality of energy demand and energy capacity of the structure. First, nonlinear static analyses are performed for five, eight and ten-story RC frame structures and pushover curves are obtained. Then the pushover curves are converted to energy capacity diagrams. Seven strong ground motions that were recorded at different soil sites in Turkey are used to obtain the pseudo-acceleration and the pseudo-velocity response spectra. Later, the response spectra are idealised with the Newmark-Hall approximation. Afterwards, energy demands for the RC structures are calculated using the idealised pseudo-velocity spectrum. The displacements, obtained from the energy capacity diagrams that fit to the energy demand values of the RC structures, are accepted as the energy-based performance point of the structures. Consequently, the target displacement values determined from the PSVS Method are checked using the displacement-based successive approach in the Turkish Seismic Design Code. The results show that the target displacements of RC frame structures obtained from the PSVS Method are very close to the values calculated by the approach given in the Turkish Seismic Design Code.
STRESS ANALYSIS OF VENTILATED BRAKE DISCS USING THE FINITE ELEMENT METHOD
Y. YILDIZ,M. DUZGUN 한국자동차공학회 2010 International journal of automotive technology Vol.11 No.1
One of the most common problems related to ventilated brake discs are crack formations, particularly under high brake loads or from the associated stresses during braking. In this study, three different ventilated brake discs, the crossdrilled disc, the cross-slotted disc, and the cross-slotted with a side groove disc, were manufactured, and their braking force performances were investigated experimentally together with a solid disc. Stress analyses were subsequently performed by the finite element method. Analyses results showed that the maximum stress generations were formed on the ventilated discs in comparison to the solid disc. However, these comparisons indicate that the application of varying force distributions along brake pads reduces the stresses on ventilated discs by 8.8% to 19.1%.
Spatial Analysis of Two-Wheeled Vehicles Traffic Crashes: Osmaniye in Turkey
Guler Yalcin,H.Sebnem Duzgun 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7
To achieve a sustainable traffic management and sustainable transportation planning in urban areas one of the tools that can be used effectively is Geographic Information Systems. In Turkey Transportation Department under Civil Engineering deals with roads and railways which are open to public such as inner city and outer city traffic arrangements with General Directorate of Security. This paper aims to analyze road traffic accident distribution according to the vehicle types involved in the accidents for urban areas in sample of Osmaniye, Turkey. While chi-square test is used for non-spatial analysis kernel density, nearest neighbor distances and Kfunction analysis are applied to determine the existence of clustering and hotspots. The network statistics are executed through SANET (Spatial Analysis on a NETwork) V4.1 that runs on ArcMap 10 and for better visualization and understanding the analysis 3D analysis are generated in ArcScene 10. It is realized that the accidents involving two-wheeled vehicles have a high percentage in all accidents. Also the possible reasons to use two-wheeled vehicles at a high rate in the city center are searched by Location Quotient Technique. The importance of this study is to use GIS as a management system for accident analysis with statistical analysis methods.
Pelvic Hydatid Disease: CT and MRI Findings Causing Sciatica
Hatice Tuba Sanal,Murat Kocaoglu,Nail Bulakbasi,Duzgun Yildirim 대한영상의학회 2007 Korean Journal of Radiology Vol.8 No.6
Pelvic masses, especially hydatid disease, rarely present with sciatica (1, 2). We present the computed tomography (CT) and the magnetic resonance imaging (MRI) findings of a 49-year-old female patient with presacral hydatid disease, who was evaluated for her sciatica. We also want to emphasize the importance of assessing the pelvis of patients with symptoms and clinical findings that are inconsistent and that cannot be satisfactorily explained by the spinal imaging findings.
Determination of earthquake safety of RC frame structures using an energy-based approach
Onur Merter,Taner Ucar,Mustafa Duzgun 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.19 No.6
An energy-based approach for determining earthquake safety of reinforced concrete frame structures is presented. The developed approach is based on comparison of plastic energy capacities of the structures with plastic energy demands obtained for selected earthquake records. Plastic energy capacities of the selected reinforced concrete frames are determined graphically by analyzing plastic hinge regions with the developed equations. Seven earthquake records are chosen to perform the nonlinear time history analyses. Earthquake plastic energy demands are determined from nonlinear time history analyses and hysteretic behavior of earthquakes is converted to monotonic behavior by using nonlinear moment-rotation relations of plastic hinges and plastic axial deformations in columns. Earthquake safety of selected reinforced concrete frames is assessed by using plastic energy capacity graphs and earthquake plastic energy demands. The plastic energy dissipation capacities of the frame structures are examined whether these capacities can withstand the plastic energy demands for selected earthquakes or not. The displacements correspond to the mean plastic energy demands are obtained quite close to the displacements determined by using the procedures given in different seismic design codes.