Isa Yesilyurt

Usak Üniversitesi · Mechanical Engineering

In machining, the tool condition has to be monitored by condition monitoring techniques to prevent damage by the use of tools and the workpiece. Cutting forces acting on the tool between zero and maximum values cause the cutting edge to crack and break. Predetection of this situation in the cutting tool is very important to prevent any negative sit...

Background Due to excessive heat generated during grinding, temperature-related failures such as burning, temper damage and re-hardening damage may occur. Grinding burn is the most common type of thermal damage, and its detection requires special attention as it shortens the service life of a machine part, affects its hardness and stress condition,...

Time-frequency methods are effective tools in identifying the frequency content of a signal and revealing its time-variant features. This paper presents the use of instantaneous features (i.e. instantaneous energy and signal phase) of acoustic emission (AE) in the detection of thermal damage to the workpiece in grinding. Both the instantaneous ener...

Time-frequency methods are effective tools in identifying the frequency content of a signal and revealing its time-variant features. This paper presents the use of instantaneous features (i.e. instantaneous energy and signal phase) of acoustic emission (AE) in the detection of thermal damage to the workpiece in grinding. Both the instantaneous ener...

This paper presents the effects of the operating conditions (i.e. cutting speed and the amount of infeed) in grinding on the occurrence of thermal damage to the workpiece. The paper commences with a brief background to the analysis methods. Firstly, the AE signals detected under different operating conditions are analysed in time and frequency doma...

Due to complex cutting edge profile of an involute cutter, calculations of chip width and consequently cutting force are quite problematical. This article presents a mechanistic approach in the prediction of cutting force components arising in the course of gear tooth cutting by an involute form cutter. To permit calculation of chip width (and so c...

This paper presents the modelling, estimation, and experimental verification of machining forces arising in the course of gear tooth cutting by an involute form milling cutter as a function of cutting depth. First of all, generation of involute gear tooth profile is carried out as the theoretical calculations of cutting force components are achieve...

This study presents the application of vibration analysis in the determination of elastic constants (i.e. Young's modulus in fiber direction, transverse Young's modulus, and shear modulus) and modal damping ratios of a unidirectional composite beam. The frequency domain approach is used for the estimation of material constants, whereas modal dampin...

Conventional methods (i.e. time, frequency and cepstrum) can routinely be used to reveal fault-indicating information in the vibration signal. In recent years, Wavelet analysis, which can lead to the clear identification of the nature of faults, are widely used to describe machine condition. Capability of this method in the detection of any abnorma...

Bending fatigue crack is a dangerous and insidious mode of failure in gears. As it produces no debris in its early stages, it gives little warning during its progression, and usually results in either immediate loss of serviceability or greatly reduced power transmitting capacity. This paper presents the applications of vibration-based techniques (...

This paper presents the energy-based method for the vibration identification of non-uniform Euler–Bernoulli beams having multiple open cracks. The method includes significant modifications for the energy-based method presented by Yang et al. [Crack identification in vibrating beams using the energy method, Journal of Sound and Vibration 244 (2) (20...

A local gear-tooth defect such as a fatigue crack, pit or chip weakens the tooth and causes transient events when that faulty tooth is in mesh. The magnitude and duration of these events depend mainly upon the severity of the defect and the contact ratio of the gear pair. If the tooth fault severity is small and the contact ratio is high, the resul...

Monitoring the condition of cutting tools in any machining operation is very important to avoid unexpected machining trouble and improve machining accuracy. This paper presents the use of vibration analysis of the cutting process in milling to indicate the presence and progression of damage incurred by an end mill. The metal cutting experiments wer...

In this study, in-plane stability analysis of non-uniform cross-sectioned thin curved beams under uniformly distributed dynamic loads is investigated by using the Finite Element Method. The first and second unstable regions are examined for dynamic stability. In-plane vibration and in-plane buckling are also studied. Two different finite element mo...

In order to discriminate small changes for early fault diagnosis of rotating machines, condition monitoring demands that the measurement of instantaneous angular speed (IAS) of the machines be as accurate as possible. This paper develops the theoretical basis and practical implementation of IAS data acquisition and IAS estimation when noise influen...

The condition of cutting tools is of particular importance for an efficient milling process in any metal cutting process to prevent additional costs and unscheduled downtime. This paper presents the use of the mean frequency of a scalogram to end mill defect detection under varying feed rates. The metal cutting experiments were performed on a mild...

Time–frequency methods, which can lead to the clear identification of the nature of faults, are widely used to describe machine condition. Capabilities of time–frequency distributions in the detection of any abnormality can further be improved when their low-order frequency moments (or time-dependent parameters), which characterise dynamic behaviou...

Time–frequency methods are effective tools for analysing diagnostics signals and have been widely used to describe machine condition. This paper introduces a time–frequency distribution, called the smoothed instantaneous power spectrum (SIPS) distribution, and demonstrates its use in the detection and location of local tooth defects in gears. The S...

Due to excessive service load, inappropriate operating conditions or simply end of life fatigue, damage can occur in gears. When a fault, either distributed or localised, is incurred by gears, the stiffness and consequently vibration characteristics of the damaged tooth will change. A possible non-destructive technique for damage detection and seve...

Combined time-frequency and time-scale methods are effective tools and widely used to describe machine condition. This paper introduces the use of Smoothed Instantaneous Power Spectrum (SIPS) distribution in the detection of a local tooth defect in gears. The SIPS distribution is derived from the Instantaneous Power Spectrum (IPS) distribution defi...