Marek Płaczek

Damping of Mechanical Vibrations Using Piezoelements, Including Influence of Connection Layer’s Properties on the Dynamic Characteristic

The paper presents analysis of flexural vibrating machatronic system. Considered system is compounded of a cantilever bending beam and a strip-like piezoelectric transducer. The transducer is bonded with the beam surface by means of connection layer which has homogeneous properties in whole length. External RC circuit is adjoined to the transducer’s clamps. This mechatronic system is loaded with harmoniousness variable force. Beam’s vibrations affect piezoelectric transducer through the agency of connection layer which generates electric charge and produces additional stiffness. Dynamic equations of considered mechatronic system were determined on the basis of elementary beam and transducer’s section dynamic equilibrium. Transducer’s dynamic equation was assigned using transducer’s piezoelectric properties. Dynamic flexibility of considered mechatronic system was assigned on the basis of approximate Galerkin’s method. Solution of beam’s differential motion’s equation was defined as a product of time and displacement’s eigenfunctions which satisfy defined boundary conditions. Dynamic characteristic of considered mechatronic system, including pure shear of the connection layer was assigned on the end of the beam and illustrated on the chart at the same time taking into account beam and transducer’s geometrical and material parameters.

Study of mechanical properties and computer simulation of composite materials reinforced by metal

In the article, two methods for testing of composite materials reinforced by sheet metal were presented. The first method is based on computer simulation of stresses in the investigated objects. It was carried out in the graphical programme NX. The second method consists in measuring deformations using strain gauge bridges and comparative analysis was carried out. The obtained results show that both methods were applied correctly and the error reaches a few percent.

Modelling and investigation of a piezo composite actuator application

This work presents a proposal of modelling and investigation of advanced piezo composite MFC actuator application in one–dimensional flexural vibrating systems. The presented method of analysis of the considered system is based on the discrete–continuous mathematical model and the approximate Galerkin method. Characteristic YV that describes relation between the beams deflection and applied voltage was calculated. The next step of the work was the analysis of influence of the piezoelectric macro fibre composites properties on the obtained characteristic of the system. The main aim of this work is to propose a mathematical algorithm of the process of modelling and analysis of systems under consideration that can be very useful in designing process. Obtained results can be used to optimise designed systems for example by selecting geometrical and material parameters of the systems elements including the glue layer between the transducer and mechanical subsystem.

Development of Mathematical Model of a Mechatronic System

This paper is a continuation of earlier publications of the authors related to the analysis of mechatronic systems including piezoelectric materials used as sensors or actuators for stabilization and damping of mechanical vibration. It was demonstrated that only very accurate mathematical model of the system with the piezoelectric transducers and external electric circuit attached to a mechanical system like a beam or a shaft by a glue layer allows the engineers to design the system with required dynamic parameters. Geometrical and material parameters of all the components have to be taken into account because neglecting the influence of one of them results in erroneous analysis results [1-4]. The paper presents the improved mathematical model of the considered mechatronic system. The assumption of pure shear of the connection layer is rejected during modeling and deformation of the layer is taken into consideration. The purpose of the reported enhancement of the mathematical model of the considered mechatronic system is to improve accuracy of computational results.

Computer-aided strength analysis of the modernized freight wagon

In the paper results of computer-aided strength analysis of the modernized freight wagon based on Finite Element Method are presented. CAD model of the considered freight wagon was created and its strength was analysed in agreement with norms described the way of such kind of freight wagons testing. Then, the model of the analysed freight wagon was modernized by adding composite panels covering the inner surface of the vehicle body. Strength analysis was carried out once again and obtained results were juxtaposed. This work was carried out in order to verify the influence of composite panels on the strength of the freight car body and to estimate the possibility of reducing the steel shell thickness of the box in order to reduce weight of the freight wagon.

Selection of Parameters of External Electric Circuit for Control of Dynamic Flexibility of a Mechatronic System

This paper deals with the analysis of mechatronic systems including piezoelectric materials used as sensors or actuators for stabilization and damping of mechanical vibration. This work presents the analysis of the flexural vibrating one-dimensional mechatronic system – a cantilever beam and the piezoelectric transducer bonded on the beam surface by means of a glue layer. The external RC circuit is connected to the transducer clamps. Dynamic equations of motion of the considered mechatronic system were written down using the discrete-continuous mathematical model, taking into consideration the influence of the connection layer and the external electric circuit. Dynamic flexibility of the mechatronic system was assigned on the basis of the approximate Galerkin method.

Influence of the excitation parameters of the mechanical subsystem on effectiveness of energy harvesting system

Piezoelectric transducers are used more and more often in modern technical devices. The wide range of their possible applications is a result of the possibility to use both direct and reverse piezoelectric effect. Nowadays, application of piezoelectric transducers in energy harvesting systems is getting more and more popular. It is caused by the easy way to convert energy of mechanical vibration to the electric voltage using piezoelectric transducers. This paper presents results of influence analysis of the vibrating mechanical subsystems excitation parameters on the effectiveness of the system designed for energy harvesting. The considered vibrating system is a composite plate with piezoelectric transducer bonded to its surface. Vibrations of the system are excited by means of an actuator with possibility to change the excitation amplitude and frequency. Recovering of electrical energy from mechanical vibrations is possible by using the direct piezoelectric effect - generation of the electric voltage while the transducer is mechanically deformed. In carried out test Macro Fiber Composite (MFC) piezoelectric transducers were used. It was proved that the time that is necessary for switch on the output voltage in analyzed system depends on the frequency of the excitation.

Dynamic Characteristics of a Piezoelectric Transducer with Structural Damping

Work presents a proposal of an analysis method of the piezoelectric transducer. The considered system is a longitudinally vibrating single PZT plate. The main aim of this work is to designate characteristics of the considered PZT plate. Using constitutive equations of piezoelectric materials and an equation of the plates motion a matrix of characteristics of the system was obtained. Relations between mechanical and electrical parameters (forces, displacements, electric current and voltage) that describe behaviour of the system are included in the matrix of characteristics. A dynamic flexibility relation between the plates deformation and a force applied to the system is considered. A structural damping of the plates material was being taken into consideration and its influence on the plates dynamic flexibility is analysed. This work is an introduction to a task of analysis of complex systems. In future work the developed model and proposed mathematical algorithm will be used to analyse piezoelectric stacks. Non-classical methods will be used. It is a part of research works of Gliwice research centre related with an analysis and synthesis of mechanical and mechatronic systems [4-7,9,10,16-18]. Passive and active mechanical and mechatronic systems with piezoelectric transducers were analysed [1-3]. Works were also supported by computer-aided methods [8]. Both classical and non-classical methods were being considered. The discussed subject is important due to increasing number of applications of both simple and reverse piezoelectric phenomena in various modern technical devices.

Modeling and Investigation of One-Dimensional Flexural Vibrating Mechatronic Systems with Piezoelectric Transducers

Piezoelectricity has found a lot of applications since it was discovered in 1880 by Pierre and Jacques Curie. There are many applications of the direct piezoelectric effect the production of an electric potential when stress is applied to the piezoelectric material, as well as the reverse piezoelectric effect the production of strain when an electric field is applied (Moheimani & Fleming, 2006). In this chapter analysis of mechatronic systems with both direct and reverse piezoelectric effects applications in mechatronic systems are presented. In considered systems piezoelectric transducers are used as actuators – the reverse piezoelectric effect application, or as vibration dampers with the external shunting electric circuit – the direct piezoelectric effect. In the first case piezoelectric transducers can be used as actuators glued on the surface of a mechanical subsystem in order to generate desired vibrations or also to control and damp vibrations in active damping applications (Kurnik et al., 1995; Gao & Liao, 2005). In this case electric voltage is generated by external control system and applied to the transducer. In the second case piezoelectric transducers are used as passive vibration dampers. A passive electric network is adjoined to transducer’s clamps. The possibility of dissipating mechanical energy with piezoelectric transducers shunted with passive electric circuits was experimentally investigated and described in many publications (Buchacz & Placzek, 2009a; Fein, 2008; Hagood & von Flotow, 1991; Kurnik, 2004). There are two basic applications of this idea. In the first method only a resistor is used as a shunting circuit and in the second method it is a passive electric circuit composed of a resistor and inductor. Many authors have worked to improve this idea. For example multimode piezoelectric shunt damping systems were described (Fleming et al., 2002). What is more there are many commercial applications of this idea (Yoshikawa et al., 1998).

An Endurance Test of Composite Panels

In this paper possibilities of freight wagons modernization using new composite materials was presented. This work was carried out under the project number PBS2/A6/17/2013 agreement implemented under the Applied Research Program, founded by the National Centre for Research and Development. All of this activities are done as consortium consists of the scientific entity – the Institute of Engineering Processes Automation and Integrated Manufacturing Systems of the Silesian University of Technology and DB Schenker Rail Poland SA and Germaz. The purpose of this article is analyse the work strength of the connection sheet metal and composite glass-epoxy with multi-point pressure. To estimate the strength of strain-gauge methods were used. The study was conducted on a stand equipped with 4 pneumatic actuators and the PLC. During the tests the same steal plate, then on a plate with mounted rivets and connection steal and composite panel were checked. Some aspects have already been presented in previous publications of the authors. This article is an extension of the previous publications with new knowledge. To determine the changes in the samples strain gauges was used. In the article original program written to the PLC in order to automatically generate pressure on the tested composites was presented. A composite material is a material having a heterogeneous structure composed of two or more components with different properties. structural components most commonly used are fibers such as glass fibers, carbon fibers and Kevlar. Currently, composites are widely used, among others, in construction, aviation, in transprcie, automotive and machinery manufacturing. In this paper research methods for detection of laminate panels damage were presented. Aspect of continuous monitoring of the technical state of the laminate is very important. As part of the work method of endurance test panels made of composite by strain gauge will be presented. In paper machine designed to periodically generate extortion will be also presented. At the Faculty of Mechanical Engineering Technical University of Silesia are conducted research on the analysis and synthesis of mechanical systems and mechatronics concern both theoretical considerations [10,11] how practical industrial tasks Recent works undertaken relate to research the properties of composite materials [1-4, 12-17] as components and assemblies railway wagons [5,8,11]. Some of the work is conducted in collaboration with other research centers [5-9].