Selçuk-Teknik Dergisi (E-Journal - Selçuk Üniversiti)
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MESNET FARKLILIKLARININ BAZALT ELYAF TAKVİYELİ KOMPOZİT BORULARIN DÜŞÜK HIZLI DARBE DAVRANIŞLARINA ETKİSİNİN İNCELENMESİ
Get PDFMESNET FARKLILIKLARININ BAZALT ELYAF TAKVİYELİ KOMPOZİT BORULARIN DÜŞÜK HIZLI DARBE DAVRANIŞLARINA ETKİSİNİN İNCELENMESİÖzetGerçekleştirilen bu çalışmada, ±55o filaman sarım BTP/Epoksi kompozit borulara iç çapı ölçülerinde dolu çelik mil yerleştirilerek, borunun içinden mesnetleme yapılmıştır. Mesnetle yapılmayan içi boş BTP/Epoksi kompozitler ile birlikte çelik mil ile mesnetlenmiş BTP/Epoksi kompozit boruların 20J ve 25J enerji seviyelerinde düşük hızlı darbe testleri gerçekleştirilmiştir. Gerçekleştirilen testler neticesinde, içi dolu çelik ile mesnetlenmiş BTP/Epoksi ve içi boş BTP/Epoksi kompozit boruların maksimum darbe kuvvetleri, deplasman değişimleri ve absorbe edilen enerji miktarları belirlenmiştir. Mesnetin ±55o filaman sarım BTP/Epoksi kompozitlerin düşük hızlı darbe davranışlarına etkisi tespit edilmiştir. Mesnetleme ile maksimum kuvvet değerinin arttığı, deplasman miktarının da düştüğü belirlenmiştir.Anahtar Kelimeler: Bazalt elyaf, Filaman sarım kompozit, Düşük hızlı darbe davranışlarıINVESTIGATION OF THE EFFECT OF SUPPORT DIFFERENCES ON LOW VELOCITY IMPACT BEHAVIORS OF BFR/EPOXY COMPOSITE TUBESAbstractIn this study, ±55o filament wound BFR / Epoxy composite tubes have been supported by a steel shaft with placing inside the composite tube according to internal diameters. Low velocity impact tests were performed at 20J and 25J energy levels for BFR / Epoxy composite tubes supported by the steel shaft and unsupported. As a result of the tests, maximum impact forces, displacement changes and absorbed energy amounts of BFR / Epoxy composite tubes supported by the steel shaft and unsupported were determined. The effects of a steel shaft support of ± 55o filament wound BFR/Epoxy composites on low velocity impact behavior were investigated. It was determined that the maximum force value increased and the amount of displacement decreased by the steel shaft support.Keywords: Basalt fiber, filament wound composite, low velocity impact behaviors
SWITCHED H2 STATE-FEEDBACK CONTROL FOR POLYTOPIC SYSTEMS BASED ON DWELL TIME
No full textThis paper introduces a H2 sub-optimal approach to design state feedback controllers for switched system with parameter uncertainty. Minimum dwell time stability analysis techniques are revisited and combined with the H2-optimal control to obtain a robust state feedback controller for switched systems. Two kinds of Lyapunov functions have been used to find a switched controller, the time varying and constant controller gains have been given for the switched system. The proposed approaches have been illustrated by means of examples
DYNAMIC ANALYSIS OF STRUCTURES WHICH ARE INSPIRED BY LATTICES OF METALS
Get PDFDesign of structures that are inspired by the Nature is gaining attention in the latest year and many studies on the lattices of the materials are being conducted. And for designing, beams and truss structures are widely used elements. Thus, when designing new structures, getting inspired by those lattices and making use of those beams and trusses might prove to be advantageous. Maintaining the estimated lifetime of the structures is also an essential factor. So, it is essential to determine the characteristics of the structures such as the deflection, stresses and more. When determining those structures, finite element analysis can be used effectively. In this study, the lattice inspired models were constructed. Inverted L-frames, inverted U-frames and 3D frames were designed by using those models. Then to analyze those structures, finite elements method was used. The frames were subjected to four different input forces which were generated by using their total weight multiplied by 10, 20, 50, 100 coefficients. The results demonstrated that these designed structures can be used in many areas such as aviation, space, construction. Also, those structures can be used as the core part of the sandwich composites
COMPARATIVE STUDY BETWEEN SENSORLESS VECTOR CONTROL AND NONLINEAR CONTROL FOR PMSM BASED ON EXTENDED KALMAN FILTER (EKF)
Get PDFAbstractThis paper presents the performance of sensorless nonlinear control compared with vector control of permanent magnets synchronous machine using Extended Kalman Filter (EKF) is used for estimating the speed. The robustness of the control is tested for the parameter variation and for the machine operating at low speed. The simulation results show the robustness of the filter and the overall drive system.Keywords: permanent magnets synchronous machine, vector control, input/output control, estimation, EKF
IMPLEMENTATION OF VIRTUAL REALITY ENHANCED CONTINUOUS PERFORMANCE TEST DESIGNED FOR ATTENTION DEFICIT HYPERACTIVITY DISORDER DIAGNOSIS
Get PDFThe purpose of the study is to implement a virtual reality (VR) enhanced continuous performance test (CPT) specifically designed as an aid to attention deficit hyperactivity disorder (ADHD) diagnosis with the newest enabling technologies. To realize such an objective, firstly, the VR technology enabled ADHD diagnosis methodologies are investigated and required metrics are analyzed. Then, a new model is constructed in order to measure the required metrics and an assessment methodology is adopted to evaluate such metrics to cooperate with the created VR application. As the contribution, a new measurement model and procedure are presented and the effectiveness of the system is going to be examined in future studies
UTILIZATION OF CHROME ORE CONCENTRATION PLANT TAILINGS AS FINE AGGREGATE IN READY-MIXED CONCRETE
Get PDFLarge amount of the chrome ore concentration plant tailings was discarded during chrome ore mining process. The accumulation of the tailings takes large areas of land for the storage and causes environmental and safety problems. When the annual consumption of the ready mixed concrete per person (approximately 1.5 m3/person) in Turkey is considered, employment of the tailings in the ready-mixed concrete may be a solution for the recovery of the tailings. In addition, using chrome tailings as a substitution for sand to produce ready-mixed concrete is a possible way to solve the resource problem of sand deficiency. The aim of this study is to investigate the utilization of the tailings taken from a chrome ore concentration plant in Eskisehir, Turkey as fine aggregate in ready-mixed concrete production. For this purpose, the tailings were partially replaced with the fine aggregate by the weight at 0, 10, 20 and 30% proportions by weight in the ready-mixed concrete mixtures. Standard curing is applied until the time of test to the 15x15x15 cm cube specimens taken from the mixtures. The unit weight, compressive strength and ultrasonic pulse velocity values of the cubic specimens were investigated in this study. Performed tests showed that replacing sand to chrome ore tailings has a potential for further investigations.
PAMUKKALE ÜNİVERSİTESİ ÖĞRETİM ELEMANLARININ ÜNİVERSİTE-SANAYİ İŞBİRLİĞİ ÇALIŞMALARINA BAKIŞLARI ÜZERİNE BİR ALAN ARAŞTIRMASI
No full textÜlkemizde son yıllarda üniversite sayısında yaşanan artışla beraber, üniversitelerde yapılan araştırma ve gerçekleştirilen proje sayısında da artış olduğu görülmektedir. Yapılan çalışmalar sonucunda elde edilen “bilgilerin” ülke sanayisinde ürüne dönüştürülememesi yapılan yatırımların rasyonel bir şekilde değerlendirilememesine neden olmaktadır. Bu açığı kapatacak olan üniversite-sanayi işbirliği (ÜSİ) çalışmalarının etkin bir şekilde gerçekleştirilmesi gerekmektedir. Son yıllarda daha fazla konuşulmaya ve uygulanmaya başlanan ÜSİ faaliyetleri inovasyon ve Ar-Ge çalışmalarında ülke ekonomisine fayda sağlayacak sonuçlar ortaya koyabilmektedir. Bu çalışmada üniversite-sanayi işbirliği çalışmalarının taraflarından birisini oluşturan üniversitelerdeki öğretim elemanlarının, ÜSİ’ye bakışları, ÜSİ yaptıkları alanlar, ÜSİ yapma amaçları belirlenmeye çalışılmaktadır. Ayrıca araştırmaya katılan fakülteler arasında kıyaslamaya gidilerek, fakülteler bazında öğretim elemanlarının değerlendirmeleri incelenmektedir. Araştırma Pamukkale Üniversitesi öğretim elemanları üzerinde yapılmıştır
ESTIMATION OF UNBALANCE COST DUE TO DEMAND PREDICTION ERRORS USING ARTIFICIAL NEURAL NETWORK
Get PDFEstimation of energy demand is used as an important tool for decision makers determining company strategies and policies. Apart from this, the fact that the actual consumption differs from the forecast is harmful for the economy of the company and even for the economy of the big scale. In this study, it is aimed to estimate the imbalance aberration caused by demand forecast deviation with Artificial Neural Networks and to evaluate its results
DESIGN OF FLOATING POINT PI CURRENT CONTROLLER FOR SPEED CONTROL OF IPMSM USING FPGA
Get PDFThe PI Controller can be considered as the essential part for efficient Speed Control of the Interior Permanent Magnet Synchronous Motor. In digital control, two platforms exist to implement this controller, namely DSP and FPGA. The FPGA is more preferred than the DSP due to the concurrent facility. To obtain the full facilities of the digital control and for high accuracy speed control of motors, floating point PI Controller should be used instead of the fixed point. The problem of the FPGA is that it is programmed using VHDL or Verilog which deals only with fixed-point representation. This paper shows a full design of floating-point PI Controller using Altera DE2i-150 platform and Altera Megafunctions. The results are proven using two simulation platforms ModelSim-Altera Starter Edition 15.0 and Matlab Simulink
EFFECTS ON THE SURFACE QUALITY IN THE MACHINING PROCESSES OF THE TOOL VIBRATIONS
Get PDFThe problem of surface quality and cutting stability in the machining processes is very important and is strictly connected with the final quality of the product. Therefore, this paper describes a new theoretical model for the dynamic cutting forces of orthogonal cutting in turning. A specific advantage for the presented model is the convenience for vibration prediction. The presented dynamic force model is used to predict variable cutting forces with dynamic cutting between cutting tool and workpiece. This model is considered two degree of freedom complex dynamic model of turning with orthogonal cutting system. The complex dynamic system consists of dynamic cutting system force model which is based on the shear angle (φ) oscillations and the penetration forces which are caused by the tool flank contact with the wavy surface