Mindaugas Jurevičius

Vibrational analysis of angle measurement comparator

The comparators of angle measurement are designed for measurement of angle gauges (limbs) and angular movements (turning) for calibration measurement errors of measuring systems. The vibration isolation issue for angle comparators is particularly relevant. Vibration analysis became essential for angle comparators operating in dynamic mode and used for precise angular measurements. In this paper, an analysis of wavelet intensity distributions of angle comparators is carried out by applying the theory of covariance functions. Data from measurements of vibrational signals at fixed points were acquired in the form of data arrays (matrices). Estimates of covariance functions between the arrays of data and the estimates of covariance functions of single arrays were calculated upon changing the quantization interval on the time scale. For signal processing, MATLAB 7 software was applied.

Vibrodiagnostics of the components of technological machines

Vibrodiagnostics of technological machine with bearings of sliding friction and of roll is done in this work. Researching technological machine is described; the main characteristics of work and photo are given. Experimental vibrodiagnostics measurements are done. Primary signals of measurement are got doing vibrodiagnostics measurements. Primary results of measurement are systematized and its analysis is done. Dependence of work characteristics between rotary systems with bearings of sliding friction and of roll is ascertained. Generalization of research results is done and conclusions are formulated.

Characteristics of Processing Water-Soluble Crystals

Method of processing water-soluble potassium dihydrogen phosphate (KDP, KH2PO4) crystal is presented in this article. Diamond wire cutting machine “RTS 440“ was used for cutting. Only one of cutting parameters – vertical feed rate of diamond wire – was varied during experiments. Other cutting parameters (speed and strain of wire, cutting method, cutting angle) were constant. Original kerosene cooling system was designed and produced. Results are presented as graphs of dependence of arithmetic average surface profile deviation Ra of KDP and cutting time on vertical feed rate. Optimal interval of feed rates was obtained.

Effect of External Excitation on Dynamic Characteristics of Vibro-Isolating Table

Performance of optical table with pneumatic vibration isolators is analyzed within 2–50 Hz frequency range. Specific vibrational excitation platform with a vibrator of the frequency range of 1–50 Hz in one of three directions were tested.The following pneumatic vibration isolator dynamic parameters were identified:transmissibility of vertical oscillation characteristics at 50 Hz frequency range;resonant frequency (vertical direction);damping efficiency at 5 Hz to 10 Hz for excitation frequencies.

Automatic Control of Loading Forces in a Tilting Pad Journal Bearing

Hydrodynamic three-tilting-pad journal bearing is analyzed. It is shown that a carrying force, stiffness of the bearing, and heat generated at journal rotation highly depend on a clearance between the journal and pads. The clearance can be controlled by measurement and control of hydrodynamic force at journal rotation. The bearing with such possibilities is described in the paper. Control of the hydrodynamic force prevents overheating of the bearing at large frequency of journal rotation, keeps necessary stiffness at small frequency of rotation, enables controlling forces loading the journal. Such a bearing is more versatile than being not controlled. Analysis and calculations are presented in the paper.

Accuracy analysis of radial velocity and distance measurement based on the Doppler effect

We present an accuracy analysis of noncontact measurement applied for the evaluation of radial velocity and distance of a moving object. The principle of velocity and distance measurement is based on the Doppler effect. Described here are the radial velocity and distance measurement principle, as well as the approach based on the Doppler effect. The accuracy of radial velocity, and distance identification of a moving object, directly depends on the stability of a laser or other radiation source. Measurement results can also be influenced by deviations of radiation source parameters and atmospheric factors. Accuracy analysis evaluation is based on probability estimation of random mistakes methodology. Evaluated are the impact of a laser or other radiation source and atmospheric parameters crosscorrelating on the accuracy of moving object radial velocity and the distance.