Cavitation noise is comprised of burst waveforms resulting from the collapse of cavitating bubbles. Any burst is the mixture of impulses from individual bubbles collapsing in close proximity. A single bubble collapse contributes either to the duration or to the amplitude or to both in the actual mixed burst. Generally, as the severity of cavitation rises, both the amplitude and the duration of impulses in the bursts increase. In any practical system, the vibroacoustic signal of cavitation is blurred by unwanted noise. As the vibroacoustic burst of cavitation is time-frequency concentrated,...
The work states the progressive method and a laser intelligent analyzer of emergencies control of the technological equipment and processing materials. A laser analyzer of the acoustooptical interactions the optical and electrical on based. The multiparametrical spectrums’ analyse of the dynamical signals from the technological equipment allows to register of the current changes condition of the cutting tool and process in whole. This series of the optoelectronical analyzers with the CNC-machine tools are coordinated and its carries out automatic control of the breakage, the cutting tool...
A method and the test and measuring system for fault detection (FD) in electronic analog circuits, based on the modified oscillation-test approach, are presented. For FD purpose the circuit under test (CUT) is forced to oscillation, which parameters are monitored. Existing faults cause deviations of measured parameters, or result in the loss of oscillation. The novelty of presented approach are technique of converting higher-order circuits to oscillators by feedback structure assignment and the solution of test and measuring system with the automatic digital amplitude control. Microprocessor...
The aim of this paper is to present possibility of application of some symptom models for prediction of machine condition. The models were obtained from energy processor (EP) which can describe general energy flaw and processing in machines.
Cutting ceramic tools are used especially at high cutting speeds in the machining process. The highly brittle type of structure and the tendency for cleavage (crack formation) are the infavorable properties of these materials, which keep their hardness at high temperatures. The hard metals are produced by sintering of the carbides such as whisker WC, TiC and TaC with the presence of Co as a binder. The high wearing resistance and high thermal strength characteristics of these materials are due to their high hardness values and due to the use of Co respectively. The main purpose of studies...
The best results of electrical motor’s diagnoses are obtained using the methods based on spectral analysis of vibration signals or on analysis of supplying currents (in the case of electrical driving systems). The most numerous group of driving system breakdowns is connected with the damages of roll bearings. In this case very effective diagnosing can be obtained using envelope signal processing (ESP) technique. The research stand elaborated in the Faculty of Electrical and Control Engineering (TUG) enables to make research with ESP diagnostic method used for rolling elements bearings as...
A new method of the state of pipe inner cavity testing is described. It is based on the exciting of Lamb waves in the wall and analysis of the amplitude - frequency characteristic or transient response.
The paper presents a computerised multichannel system for monitoring of spinning processes in textile industry. The system operates ‘on-line’, directly on the rotor spinning machine without interrupting its work. Continuous measurements of three important spinning process parameters are taken, i.e., coefficient of mass variation of sliver, coefficient of mass variation of yarn, and yarn tension. Measurement data is stored in the computer so making further ‘off-line’ analysis and conversion possible. The modelled feed stream of fibres is used to generate the Multifrequency Binary Signal (MBS)...
The paper presents the method of fault location of the piecewise linear type analog circuits based on the verification approach and the component connection model. For verification of the fault hypothesis the residual square sum criterion is applied. In the first part of the paper the diagnostic equations describing the model and the algorithm of the method are presented. Theoretical considerations have been illustrated on the example of single and double fault diagnosis of the three-stage transistor amplifier.
A calibration procedure using an air-jet as the artificial AE source was applied to single-point tool wear monitoring. The calibration procedure involves setting up an air-jet at a fixed stand-off distance from the top rake of the tool tip, applying in sequence a set of increasing pressures and measuring the corresponding AE. The root-mean-square value of the AE (AErms) obtained is linearly proportional to the pressure applied. This paper presents the results of machining tests and air-jet pressure test, both of which confirm that the tool system is linear with respect to AE propagation....