Evci, Celal
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Name Variants
Evci, C.
C., Evci
E., Celal
Evci,C.
C.,Evci
E.,Celal
Celal, Evci
Evci, Celal
C., Evci
E., Celal
Evci,C.
C.,Evci
E.,Celal
Celal, Evci
Evci, Celal
Job Title
Doktor Öğretim Üyesi
Email Address
celal.evci@atilim.edu.tr
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
4
Articles
3
Citation Count
59
Supervised Theses
0
4 results
Scholarly Output Search Results
Now showing 1 - 4 of 4
Article Citation Count: 5ANALYSIS OF THE EFFECT OF PROPELLANT TEMPERATURE ON INTERIOR BALLISTICS PROBLEM(Yildiz Technical Univ, 2018) Evci, Celal; Isik, H.; Department of Mechanical EngineeringThis study investigates the effect of conditioning temperature of double base propellants on the interior ballistic parameters such as burning gas temperature, barrel wall temperature, pressure and stresses generated in the barrel. Interior ballistic problem was solved employing experimental, numerical and analytical methods with a thermo-mechanical approach. Double base propellants were conditioned at different temperatures ( 52, 35, 21, 0, -20, -35, -54 degrees C). The maximum pressure in the barrel and projectile muzzle velocity were measured for all the propellants by conducting shooting tests with a special test barrel using 7.62x51 mm NATO ammunition. Vallier-Heydenreich method was employed to determine the transient pressure distribution along the barrel. The temperature of burnt gases was calculated by using Noble-Abel equation. The heat transfer analysis was done using the commercial software ANSYS to get the transient temperature and stress distributions. Temperature distribution through the barrel wall thickness was validated using a FLIR thermal imager. Radial, circumferential and axial stresses and corresponding equivalent Von Misses stresses were determined numerically and analytically. The results of the analytical solution for stress analysis validated the finite element solution of interior ballistic problem. Increasing the initial temperature of the propellant resulted in higher temperature and pressure inside the barrel which in turn increased the stresses in the barrel.Article Citation Count: 46Functionally graded hollow cylinder under pressure and thermal loading: Effect of material parameters on stress and temperature distributions(Pergamon-elsevier Science Ltd, 2018) Evci, Celal; Gulgec, Mufit; Department of Mechanical EngineeringThis study presents an analytical solution of stresses and displacements in a long functionally graded (FGM) hollow cylinder subjected to uniform heat generation and internal pressure. Thermo-elastic material properties of FGM cylinder continuously vary in radial direction along the thickness with a power function. The temperature distribution is assumed to vary as a function of the radial coordinate and in steady state. Stress formulation approach is employed using the Airy stress function to derive the analytical solution. In the failure analysis of FGM cylinder, Coulomb-Mohr theory is applied for the ceramic phase whereas Tresca yield criterion is used for the metal phase. The stress analysis reveals that stresses in FGM cylinder decrease considerably, compared to the homogenous one, for a particular interval of material parameters. Radial displacement analysis in FGM cylinder supports the results obtained from stress analysis. (C) 2017 Elsevier Ltd. All rights reserved.Conference Object Citation Count: 4The Effect of the Impactor Diameter and Temperature on Low Velocity Impact Behavior of CFRP Laminates(Amer inst Physics, 2017) Evci, Celal; Uyandiran, I.; Department of Mechanical EngineeringImpact damage is one of the major concerns that should be taken into account with the new aircraft and spacecraft structures which employ ever-growing use of composite materials. Considering the thermal loads encountered at different altitudes, both low and high temperatures can affect the properties and impact behavior of composite materials. This study aims to investigate the effect of temperature and impactor diameter on the impact behavior and damage development in balanced and symmetrical CERT' laminates which were manufactured by employing vacuum bagging process with autoclave cure. Instrumented drop-weight impact testing system is used to perform the low velocity impact tests in a range of temperatures ranged from 60 down to -50 degrees C. Impact tests for each temperature level were conducted using three different hemispherical impactor diameters varying from 10 to 20 mm Energy profile method is employed to determine the impact threshold energies for damage evolution. The level of impact damage is determined from the dent depth on the impacted face and delamination damage detected using ultrasonic C-Scan technique. Test results reveal that the threshold of penetration energy, main failure force and delamination area increase with impactor diameter at all temperature levels. No clear influence of temperature on the critical force thresholds could be derived. However, penetration threshold energy decreased as the temperature was lowered. Drop in the penetration threshold was more obvious with quite low temperatures. Delamination damage area increased while the temperature decreased from +60 degrees C to-50 degrees C.Article Citation Count: 4Effect of welding wire and groove angle on mechanical properties of high strength steel welded joints(Wiley-v C H verlag Gmbh, 2017) Evci, Celal; Isik, H.; Macar, M.; Department of Mechanical EngineeringMechanical properties of high strength steel welded joints strictly depend on the welding process, the filler material composition and the welding geometry. This study investigates the effects of using cored and solid welding wires and implementing various groove angles on the mechanical performance of weld joints which were fabricated employing the gas metal arc welding process. It was found that weld joints of low alloy, high strength steels using low alloy steel cored welding wires exhibited higher tensile strength than that of low alloy steel solid wire and chromium-nickel steel bare welding wire when the method of gas metal arc welding is employed. The effect of groove angle on the strength and toughness of V-groove and double V-groove butt-joints was investigated. V-groove joints, with higher tensile strength than double V-groove joints in the whole range of groove angles, were superior in toughness for small groove angles, but impact toughness values of both joints were comparable for large angles. The effect of heat input and cooling rate on the weld microstructure and weld strength was also investigated by performing thermal analysis employing the commercial software ANSYS. It was concluded that cooling rate and solidification growth rate determined the microstructure of the weld zone which had great consequences in regard to mechanical properties.
