Investigation of magneto-rheological fluid parameters using cantilever -type piezoactuator

There has been a growing interest in the on-line detection of viscosity of magnetorheological fluids since it is a critical parameter that is sensitive to material property changes caused by chemical reactions, sedimentation process and magnetic field. Online monitoring of viscosity and density offers a powerful means for controlling the quality of magneto-rheological fluids and processes involving fluid environment

Research of ultrasonic assisted turning tool

In turning process surface quality can be improved by using an ultrasonic assisted tool. Therewith surface roughness of work piece is better in comparison to traditional turning. Moreover, application of ultrasonic turning results in lower rate of wear of cutting tool insert. In the present study custom-made cutting tool was used, while the vibrations were generated by piezoelectric transducer. A numerical model was developed for thorough analysis of ultrasonically assisted turning tool. Performed simulations revealed the type of vibrations that are the most influential for improvement of the turning process. This information is valuable for selection of optimal parameters for achieving the best effec

Development of laser beam light intensity control system

The paper proposes a novel laser beam light intensity control system, which functionality is based on piezoelectric actuators and special membrane that is comprised from two gratings. Geometrical adjustment between adjacent pores in both plates results in zero light intensity through the membrane when no control signal is activated. Displacement of one of the control membrane plates with micro pores generates effects which are exploited for laser beam flow power control

Investigation of motion control of piezoelectric unimorph for laser shutter systems

This paper presents the design and testing of a resonance frequency-tunable piezoelectric unimorph chopper and shutter that employ a magnetic force technique and magnetorheological fluid (MRF). This technique enabled to increase the frequency of the resonance up to 110% of the untuned resonant frequency. A piezoelectric unimorph cantilever with a natural frequency of 126 Hz is used as the laser beam chopper or shutter, which is successfully tuned in a frequency range of 126 - 270 Hz thereby enabling continuous control of the laser beam over the entire frequency range tested. A theoretical model based on variable magnetic field strength and MRF damping is presented. The magnetic force and MRF applied for damping of transient vibrations of the piezoelectric unimorph shutter have been experimentally determine

Development and investigation of novel design piezo-actuated laser beam shutting system

In this paper authors investigate the developed laser beam shutting system of a new design. The scheme of considered laser beam shutter and working principle are explained. Numerical analysis and experiments were performed for the laser beam shutting system. A finite element (FE) model of thin plate was constructed for numerical analysis. The model was solved by means of COMSOL nonlinear buckling analysis of the thin plate and using solid stress-strain application mode. Comparative analysis of theoretical and experimental research results of the developed laser beam shutting system was performe

Experimental study of coupled dynamic and electric characteristics of piezoelectric energy harvester under variable resistive load

The paper presents experimental study of dynamic and electric characteristics of cantilever-type bimorph piezoelectric energy harvester at the presence of varying resistive loads spanning from short circuit to open circuit conditions. Frequency response measurements of tip displacement and voltage output were performed in a setup with a differential laser Doppler vibrometer. Reported results include resonant frequency, tip displacement, quality factor as well as generated voltage, current and power. It is demonstrated that the magnitude of connected electrical load significantly influences power generated by the harvester as well as other characteristics. The trends in experimentally obtained data are analyzed and reasons behind them are discussed. Conducted experimental study allowed to characterize coupled mechanical and electrical performance of the standard piezoelectric energy harvester with well-defined geometric and material properties under variable electrical loading conditions. Measurement data will be used for verification and updating of the developed finite element model

Application of laser methods for identification of authenticity of documents fabricated from thermoplastic composite material

Processes of globalization and integration are pervasive all over the world, and rapid innovation of advanced transportation systems resulted in enormous increase in number of persons travelling cross-border. Normally, persons crossing the border are checked at the first control line. Therefore, application of innovative methods that allow identification of partial alterations in a document or a fully counterfeit document, for initial checking of documents remains a relevant issue. The holographic interferometry represents one of the non-destructive control methods applicable for document check that enables assessment of defects in the entire area of a document being checked. This paper presents validation of the real-time method of holographic interferometry used for document check as well as parameters of a holographic setup, description of document investigation and analysis of the obtained finding

Passive optimal tool structures for vibration cutting

Higher surface quality of the machined workpiece is obtained when the cutting tool is excited at high-frequency vibrations that are superimposed on its continuous movement. Traditionally excitation of high-frequency vibrations at the tool cutting edge needs special equipment, which poses challenges for implementation of such vibrational cutting tool in industrial environment. More effective could be the passive way with respect to structural changes of the tool. The main idea is based on the intensification of higher vibration modes of a cutting tool as a flexible structure. Higher modes are characterized by higher frequencies and lower vibration amplitudes, which induces vibrational cutting effect that results in a better quality of the machined surface. Furthermore, intensification of a higher mode increases the magnitude of internal energy dissipation inside tool material and thereby makes the tool a more effective damper, which positively influences the amplitudes of workpiece or machine tool itself, providing the possibility to reduce chatter

Investigation of Oil - Water Ultrasound Emulsifier

Diesel fuel and water emulsifier designed for diesel fuel contaminated with water mixing to improve fuel combustion properties, it could also be used as mixing device for water and diesel fuel mixture. Examined literature describing the oil and water mixture emulsifiers. Analyzed the experiments related to diesel fuel and water emulsion combustion and distribution of its water volume. It has been developed and described principle emulsifier scheme. Calculated and modeled piezoelectric ultrasonic vibration actuator, which causes cavitations in mixing chamber. Ultrasonic vibration actuator is designed for the cavitation emulsion processing. Comparing experimental data with calculations obtained less than 10% deviation from the theoretical resonance frequency values. Performed experimental testing of ultrasonic vibration actuator to determine its resonance values. It also performed test of the distribution of water drops in diesel fuel using a microscope. Diesel fuel combustion effluents is one of the major problems stopping air pollution, especially in more populated areas

Control of piezoelectric scanner dynamics using magnetorheological fluid

The developed one-dimensional laser beam scanner, driven by a piezoelectric disctype unimorph actuator is presented in this paper. The dynamics of a piezoelectric actuator is analyzed. A magnetorheological fluid (MRF) damper is used to eliminate transient vibrations of the scanner eigen frequencies induced by the stepped driving voltage. Experimental results demonstrate the effectiveness of the MRF damper in residual-vibration reduction in the laser beam scanner