Browsing by Author "Anil O."

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    Nonlinear finite element analysis of impact behavior of concrete beam
    (Association for Scientific Research, 2011) Kantar E.; Erdem R.T.; Anil O.
    The least well known loading type is the impact loading that are affecting on to RC structures. Several impact tests have been used to demonstrate the relative brittleness and impact resistance of concrete and similar construction materials. However, none of these tests has been declared to be a Standard test, at least in part due to the lack of statistical data on the variation of the results. In this study; total ten beam specimens at which five of them are manufactured from normal concrete compression strength without reinforcement are manufactured. Remaining five had high concrete compression strength. These specimens are tested under the impacts loading that are applied by dropping constant weight hammer from five different heights. The acceleration arises from the impact loading is measured against time. The change of velocity, displacement and energy is calculated for all specimens. The failure modes of the specimens with normal and high concrete compression strength are observed under the loading of constant weight impact hammer that are dropped from different heights. A finite element model that is made by using ABAQUS software is used for the simulation of experiments and model gave compatible results with experiments. © Association for Scientific Research.
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    Low velocity impact behavior of concrete beam strengthened with CFRP strip
    (Techno Press, 2012) Kantar E.; Anil O.
    Nowadays CFRP (Carbon Fiber Reinforced Polymer) became widely used materials for the strengthening and retrofitting of structures. Many experimental and analytical studies are encountered at literature about strengthening beams by using this kind of materials against static loads and cyclic loads such as earthquake or wind loading for investigating their behavior. But authors did not found any study about strengthening of RC beams by using CFRP against low velocity impact and investigating their behavior. For these reasons an experimental study is conducted on totally ten strengthened RC beams. Impact loading is applied on to specimens by using an impact loading system that is designed by authors. Investigated parameters were concrete compression strength and drop height. Two different sets of specimens with different concrete compression strength tested under the impact loading that are applied by dropping constant weight hammer from five different heights. The acceleration arises from the impact loading is measured against time. The change of velocity, displacement and energy are calculated for all specimens. The failure modes of the specimens with normal and high concrete compression strength are observed under the loading of constant weight impact hammer that are dropped from different heights. Impact behaviors of beams are positively affected from the strengthening with CFRP. Measured accelerations, the number of drops up to failure and dissipated energy are increased. Finite element analysis that are made by using ABAQUS software is used for the simulation of experiments, and model gave compatible results with experiments.
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    Estimation of compression strength of polypropylene fibre reinforced concrete using artificial neural networks
    (2013) Eredm R.T.; Kantar E.; Gücüyen E.; Anil O.
    In this study, Artificial Neural Networks (ANN) analysis is used to predict the compression strength of polypropylene fibre mixed concrete. Polypropylene fibre admixture increases the compression strength of concrete to a certain extent according to mix proportion. This proportion and homogenous distribution are important parameters on compression strength. Determination of compression strength of fibre mixed concrete is significant due to the veridicality of capacity calculations. Plenty of experiments shall be completed to state the compression strength of concrete which have different fibre admixture. In each case, it is known that performing the laboratory experiments is costly and time-consuming. Therefore, ANN analysis is used to predict the 7 and 28 days of compression strength values. For this purpose, 156 test specimens are produced that have 26 different types of fibre admixture. While the results of 120 specimens are used for training process, 36 of them are separated for test process in ANN analysis to determine the validity of experimental results. Finally, it is seen that ANN analysis predicts the compression strength of concrete successfully.
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    Vibration measurement and vulnerability analysis of a power plant cooling system
    (Techno-Press, 2013) Anil O.; Akbaş S.O.; Kantar E.; Cem Gel A.
    During the service life of a structure, design complications and unexpected events may induce unforeseen vibrations. These vibrations can be generated by malfunctioning machinery or machines that are modified or placed without considering the original structural design because of a change in the intended use of the structure. Significant vibrations occurred at a natural gas plant cooling structure during its operation due to cavitation effect within the hydraulic system. This study presents findings obtained from the in-situ vibration measurements and following finite-element analyses of the cooling structure. Comments are made on the updated performance level and damage state of the structure using the results of these measurements and corresponding numerical analyses. An attempt was also made to assess the applicability of traditional displacement-based vulnerability estimation methods in the health monitoring of structures under vibrations with a character different from those due to seismic excitations.
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    Improving the impact behavior of pipes using geofoam layer for protection
    (Elsevier Ltd, 2015) Anil O.; Erdem R.T.; Kantar E.
    In scope of this study performances of protective layers, proposed to protect the pipes from sudden impact loads such as rock falls, are aimed to be compared. In this study, performance, strength and energy absorption capability of geofoam structures against impact forces are investigated by using drop weight impact testing apparatus. Pipes that are manufactured from steel and composite materials are tested with only 130 mm thick sand protecting layer without any geofoam structure, and with two different geofoam with different thicknesses. Results are presented in a comparative form and the effect of geofoam on the impact behavior of sand layer is investigated. Impact load and accelerations on the pipes are measured with respect to time during experiments. Absorbed energy by the pipes are calculated and compared with each other for determining performance of the different protective structures. From the study, it was observed that the sand and geofoam layers used as protective layers were generally successful by reducing the detrimental effects of impact loads in terms of dissipating impact effects on the pipes and the measured acceleration and displacement levels. The best result is obtained from the 50mm thick geofoam with sand layer. Finite elements analyses are performed by using ABAQUS software and both test and analysis results are compared to obtain a model that can give an idea to designers. © 2015 Elsevier Ltd.
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    Investigation of damaged formwork timber beam retrofitting with anchoraged CFRP strip under different loading
    (Techno-Press, 2024) Turer A.; Anil O.; Cevik A.; Tugrul Erdem R.
    Construction of high-rise structures, formwork systems that can be installed quickly, resistant to external loads, can be used more than once, have become a necessity. Timber and composite timber materials are preferred in the formation of such formwork systems due to their durability, ease of assembly, light weight and easy to use more than one time. Formwork beams are the most commonly used structural component in the formation of such formwork systems, and these beams can be damaged for different reasons during their lifetime. In this study, H20 top P type timber formwork beams with 1800 and 2450 mm length which is among the products of DOKA(c) company is damaged under the effect of static loading up to a high load level of 85% of the maximum ultimate capacity and after being retrofitted using anchored CFRP strips, performance and behavior of the beams under the influence of various loading types such as static, fatigue and impact are investigated experimentally. Two different lengths of retrofitted timber formwork beams were tested by applying monotonic static, fatigue and impact loading and comments were made about the effects of the retrofit method on performance under different loading types. © 2024 Techno-Press. All rights reserved.