International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Condition monitoring of production equipment is an important task in any industrial production. This article describes the features of laser alignment of worm gearboxes and its effect on the temperature and vibration level of rolling bearings. The necessity of periodic temperature and vibration signal measurements and analysis of bearing’s condition for timely forecasting of equipment condition and planning of repairs, is also justified

The paper focuses on the security of fiber optic infrastructures. The main purpose of the paper is present the vibration detection system for unauthorized access to the fiber optic infrastructure detection. For this purpose, measurement of vibrations using the interferometric method and the measurement based on state of polarization changes evaluation is presented. For the measurement own designed systems were used. Both systems are theoretically described and the principles of use are explained. The measurement was performed at an experimental workplace in a laboratory at the university Based on evaluation measurement both systems are compared in term of sensitivity.

The materials of the article consider the influence of external mechanical loads of static and dynamic action (pressure force, mechanical impulse, vibration) on the change of electrophysical characteristics (electrical conductivity, specific capacitance) of film sensor elements. It is shown that an increase in the mechanical load on such an element with a simultaneous decrease in the interact ion time with a constant contact area leads to an exponential increase in the power and sensitivity of the reaction pulse, provided that such mechanical load does not exceed the mechanical strength of the sensor element. At the same time, the increase in the mechanical load on the sensor element at constant time and contact area, almost does not change the sensitivity of the reaction pulse (the maximum increase in sensitivity does not exceed 1.8%). In this case, vibrational oscillations in the frequency range 30… 85 Hz at mechanical forces of the order of 20 … 150 mN create response pulses of the order of 12… 45 mV/μs, which are perceived as “false positives” of the sensor elements. A further increase in frequency and mechanical effort leads to the destruction of the base of the sensor element and the detachment of the sensor f ilm from the base. Reducing the frequency and mechanical forces create reaction pulses up to 12 mV/μs, which does not exceed the allowable values of “white noise” (about 25… 35% of the minimum value of the reaction pulse).

Main directions and trends of mechanism and machine mechanics developing in Belarus are considered. Results of investigations fulfilled in the Joint Institute of Mechanical Engineering and V.A. Bely Metal Polymer Research Institute of NASB, Belarusian National Technical and Belarusian-Russian Universities, as well as in Belarusian State Transport University and other Belarusian research centers are presented. Generally, these investigations are forwarded for modernization of drives of various machines and mechanisms, including mobile machines, instrument mechanisms and estimation of their operation characteristics in the frame of “Industry 4.0” conception. The paper is divided into two parts. The first part focuses on gears and powertrains. Parts of the paper contain sources of information and main publications of Belarusian scientists. Thus, the paper as a whole bears informational and bibliographic character

Тhe article deals with probabilistic and statistical models of vibration processes. The covariance moment is considered. A dimensionless normalized covariance is introduced. To evaluate these theoretical characteristics, we used a statistical set of observational data. Observations that are cleared of measurement errors are combined into a sample of a specific volume. Random processes in vibration analysis are considered in detail. The characteristics of random processes are given: attenuation with a random beginning, a linear process with a random slope, and a harmonic process with a random amplitude. A statistical model of a linear system based on observations of input and output vibration processes is considered in detail.

This paper describes the results of numerical simulations of a vehicle engine with dual mass flywheel coupled with dynamometer. The differential equations of the model are given. The mass moments of inertia and the torsional stiffness are taking into account. Numerical simulations are carried out. Natural frequencies of the system are determinate. Bode diagrams of the system are shown and analysed. Recommendations to reduce vibration by using an additional flexible coupling are given.

The subject of the paper, titled ‘Multistage Gear Project Of The Electrical Car SGR2016 for the Silesian Greenpower organization’, is an analysis of a chain vibrations in drive gear of SGR 2016 bolide. The exact moment of gear switch presents the greatest threat of a stability loss. Tests have been conducted in 2 stages. The first stage was the determining of derailleur setting. The adjusted component was a mechanism responsible for increasing the drag movement of derailleur cage. Adjustment of this element caused change in vibration characteristics in different system parts. That element was adjusted so oscillations were minimized. The second stage of studies was pinpointing the correct rotational speed, at which gears should be changed, using previously defined derailleur adjustment. Speed, at which the gear switch takes place, was chosen so the vibrations are lowest possible. Oscillation amplitude was recorded using high speed camera, and the data was analyzed using a dedicated High Speed AVI software. Speed measurement had been done using magnetic field sensor. All studies have been conducted on inertial system, simulating real life race conditions. Comparing all results, optimal driving parameters in terms of drive gear work stability, have been defined.

This paper describes the results of numerical simulations of a vehicle drivetrain model with dual mass flywheel. The differential equations of the model are given. The vehicle inertia, the tire torsional stiffness and the transmission gear ratios are taking into account. Numerical simulations with given mass, elastic and damping parameters are carried out. Natural frequencies of the system are determinate. Vibrational characteristics of the system are shown and analysed.

Predictive maintenance of machines, also known as Condition Based Maintenance, is based on monitoring operating parameters, and comparison with corresponding values of parameters obtained for the new equipment.

All machines with moving parts give rise to sound and vibration and each machine has a specific vibration signature related to the construction and the state of the machine. If the state of the machine changes the vibration signature will also change and a change in the vibration signature can be used to detect incipient defects before they become critical. The condition monitoring technique is based on detecting the presence of a fault, diagnosing the root cause of the fault, assessing its level of severity and making arrangements for its correction. A broad of condition monitoring and fault diagnosis techniques has been carried out for improving the accuracy and ability of condition monitoring and prognosis systems for bearing and gear components.

This paper introduces the method for diagnostic of the rear drive axle for the passenger cars without its demounting. The objective method of diagnosing the rear drive axle is done by vibrometer. Application of diagnostic method greatly would be contributed in quickly localization of the rear drive axle fault where diagnostic process of the servicer will done faster.

The paper addresses the issue of identifying a technical state of rotating parts with the use of vibrodiagnostics. This method has been developing rapidly for recent years and is assumed to be used for predicting failure occurrence. In this paper we focus on monitoring a technical state of a medium truck bearing box where we simulate different field conditions and their dependence on the RMS – root mean square. A measuring device DEWE 50/8 including the DEWEsoft software product of the Dewetron company have been used for the actual measurement. The aim of the work is to calculate the values of root mean square acceleration up to the moment a failure occurs. In the next step we will put the values into a graph and try to determine a gRMS limiting value. In the future this enables us to change the bearing before a failure occurs otherwise it would increase the related cost.

The subject of research in this paper is a conveyor drive unit from a conveyor coal transport system that is used by SM "Brod – Gneotino" to SM "Suvodol" (Power plant REK Bitola-Macedonia) because of its existing signs of increased vibrations. Vibration measurements of the drive transporter T5 was obtained to determine the vibration state of the drive unit. Each driveline (electric motor – hydro clutch – gear reducer) has ten measuring points – probes to monitor temperature and ten measuring points – probes for monitoring the vibration of the electric motor bearings and bearings of the gear reducer.

Through proper FFT analysis of the vibration signal that has been obtained by the probes we will determine further conclusions and recommendations regarding the state of the elements of the system and their dynamic stability.

The paper presents concepts related to analysis of mechanical vibrations of a squirrel-cage induction motor. It describes an experimental approach using piezoelectric accelerometer and analog/digital data acquisition tools. The influence of powering the motor with an inverter on vibration harmonic content is presented and different PWM switching frequencies are compared to regular line supply.