Abdulkadir Cengiz

A Methodology for Cutting Force Prediction in Side Milling

This article describes a methodology based on force distributions for predicting cutting forces in side milling 7075-T651 aluminum. The methodology includes a practical mechanism for gathering experimental data. Milling forces on each disc are measured by experimentally dividing the cutter into discs for determining the milling coefficients. Force distributions are characterized as functions of cutting and edge forces, including cutter geometry and cutting parameter effects. In contrast to previous researches, the coefficients are determined considering relations between load and shear. Owing to its high performance, this methodology can be effectively used to improve machining accuracy in side milling.

A Novel Failure Diagnosis System Design for Automotive Timing Belts

In this study, a novel failure diagnostic system for timing belts was developed in order to prevent a catastrophic belt failure. These failures may occur before running out the nominal belt life and lead to an extensive engine damage, thereby resulting costly repairs. Timing belt failures are generally resulted from three reasons, that is, lack of a tooth, fiber separation on belt sides, and teeth splitting. Three optical sensors with laser beam whose diameter is 0.6 mm was located on suitable positions and it is used to produce error signal resulted from disturbance of laser beam flows due to failure. The error signal is processed by the processor, which is independent from the electronic control unit (ECU) to alert the driver or ECU, directly. Experimental apparatus which consists of two camshaft pulleys and an idler pulley with belt tensioner has been set up to simulate real engine conditions. Experimental results show that the optical monitoring technique is reliable to determine timing belt failure types simultaneously in the range of 500–7000 rpm engine speed and it is also easier, low cost and more applicable than other methods such as vibration monitoring.

Experimental identification of the torque losses in V-ribbed belt drives using the response surface method

A drop in the transmitted torque is one of the concerns regarding the performance of belt drives, which affects the efficiency of the power transmission. In this study, the torque loss behaviour of a V-ribbed belt drive with two equal-sized pulleys is investigated using several experimental methodologies. The individual effects of belt-drive parameters are determined with the one-factor-at-a-time test method. The relation between the parameters and the torque loss is found via response surface methodology. Afterwards, the operating conditions are optimized for the minimum torque loss. A test is conducted using the optimum parameter values. The difference between the percentage torque loss predicted by the response surface curve and the experimental result is found to be 8.5%. Furthermore, the predicted model looks reasonably accurate on the basis of the analysis of variance and the residual analysis. Using the response curve, the torque loss may be estimated for similar belt drives.

A development of electromagnetic retarder controller to stabilise vehicle speed by using PWM technique

Deceleration of heavy vehicles on long downhill runs is an important problem. Because of heavy loads, they have a huge amount of kinetic energy to be absorbed. Electromagnetic retarders are widely used on heavy vehicles owing to low operating and maintenance costs. In this study, a braking control system that can be easily applied to existing electromagnetic retarders of vehicles was designed and tested experimentally. The goal of the proposed system is deceleration of the vehicle and stabilisation of the speed at a desired value by using an electromagnetic retarder. To achieve this goal, a closed-loop pulse width modulation (PWM) braking controller was designed. For the experiments, an experimental set-up consisting of an electromagnetic retarder and an engine was built. As a result of experiments, the engine running at a constant speed was decelerated in a controlled manner with a 4% steady-state error according to setpoint values.

Torque Loss Measurements on Poly V-Ribbed Belt Drive Systems

Efficient belts can provide the same magnitude of energy savings as energy-efficient motors. Therefore, belt drives deserve greater attention, so that their losses should be minimized. The belt drive power losses are a combination of torque losses and speed losses. However, the determination of belt drive behavior in terms of power losses requires extensive experimental investigations. Therefore, in this study, belt slip and torque losses were investigated experimentally with a laboratory constructed test bench. Measurement System Analysis (MSA) was performed in order to investigate the test rig reliability. Special attention was paid for experimental test setup, testing and modeling of torque loss behavior of V-ribbed belt drive systems. Significant design parameters were investigated.Copyright

V-KAYIŞI MEKANİZMALARINDA SICAKLIK VE NEMİN KAYMAYA ETKİSİNİN DENEYSEL İNCELENMESİ

Bu calismada, sicaklik ve nem parametrelerinin V-kayis kasnak mekanizmalarinin verimine etkisitanimlanmistir. Cevre sartlari altinda, V-kayis ile kasnak arasindaki kaymanin olculmesi amaciyla bir deneyprogrami gerceklestirilmistir. Bu calismanin hedefi, tahrik parametrelerine bagli olarak V-kayis kasnakmekanizmasinin cevre kosullari ile kayma miktari arasinda bir korelasyon kurulmasina yoneliktir. Bu korelasyoncoklu lineer regresyon analizi ile gerceklestirilmistir. Calismanin sonucunda, farkli sicaklik ve nem kosullarialtinda V-kayisi ile kasnak arasindaki surtunme katsayisini, 0.97 korelasyon katsayisiyla belirleyebilen birtahmin denklemi olusturulmustur. Sicaklik ve nemdeki artisin, surtunme katsayisinin dusmesine dolayisi ilekaymanin artmasina sebep oldugu gorulmustur. Yuksek nem sartlarinda ve sicakligin 60oC ile 80oC arasindakicevre kosullarinda kayma miktari oldukca yukselmektedir.