Jerzy Wiciak

Bio: Jerzy Wiciak is an academic researcher from AGH University of Science and Technology. The author has contributed to research in topics: Vibration & Sound pressure. The author has an hindex of 7, co-authored 52 publications receiving 168 citations.

Active and passive structural acoustic control of the smart beam

Abstract: Structural noise and vibrations control can be achieved using two strategies: active - with feed-forward controller, a sensor and an actuator [1-3] or passive, by piezoelectric shunt damping [4-8], when a piezoelectric transducer will act as a sensor and an actuator. Potential applications of these structures are investigated. Two numerical (FEM) models based on the active and passive damping strategies are compared. The numerical solutions were confirmed experimentally.

Active Vibration Control of Rectangular Plate with Distributed Piezoelements Excited Acoustically and Mechanically

Abstract: The paper presents simulations and research results of testing of the aluminium plate with active vibration control. The aim of this paper is to analyze and compare two ways of excitation of the test plate, various influence on its vibrations and active damping control. Vibration control of the smart structure is realized through four piezoceramic PZT actuators and one PZT sensor bonded to the plate. Simulations and numerical computations of the structure are performed in ANSYS environment. Measurements are executed on specialized sound insulation suite for small elements in reverberation chamber. At the beginning white noise sound source is used in purpose to measure basic vibration modes. After numerical computations and measurements three particular frequencies has been chosen and for them active damping is applied. There are two ways of exciting the test plate; first method is sound wave, second is mechanical vibrations via one of piezoceramics. The test results indicate that PZTs can decrease vibrations by approximately 15 dB for a pure sound input with acoustic excitation method, for mechanical excitation method 18 dB for a sinus vibration signal is achieved.

Modelling of vibration and noise control of a submerged circular plate

Abstract: This paper presents a numerical approach for modelling of a thin circular plate clamped on the edges in a rectangular enclosure and containing distributed piezoelectric actuators under dynamic mechanical and electrical loadings. The plate is also loaded on one side by heavy fluid (water) and on the other side contacts with air. The finite element method analysis was performed, supported by the ANSYS computer package. The numerical solutions were confirmed experimentally. The obtained results demonstrate a significant reduction of the vibration level and sound pressure level with the use of piezoceramic actuators.

Sound radiation by set of L-jointed plates with four pairs of piezoelectric elements

Abstract: In the paper the possibilities of reducing the amplitude of structural vibrations and radiated noise in the way of use of piezoelectric actuators are discussed. The tests were done for the L-jointed aluminium plates. On one of its surfaces there were mounted four piezoelectric actuators and on the opposite one there were placed four piezoelectric sensors. The one of the four actuators was used as vibrations generator, while the remaining ones were used for vibration control. The influence of activation and mode shape form on the structure's response were investigated. The finite element method [15] analysis was performed, with the application of ANSYS computer package [1]. The numerical solutions were confirmed experimentally.

Reduction of structural noise inside crane cage by piezoelectric actuators -FEM simulation

Abstract: In the paper the finite element simulations of the reduction of the noise inside the crane cage by piezoelectric actuators glued to chosen external walls is discussed. The whole cage structure and internal acoustic medium is modelled and piezoelectric elements are dispersed. The first two lower natural frequencies are considered. The completely different results of reduction are obtained for the analysed modes. The aim of the analysis is to show the possibility of application of piezoelectric elements to active noise and vibration cancellation for the realistic machine structure as crane cage.

Active control of vibration, 1st edition

Abstract: This book is a companion text to Active Control of Sound by P.A. Nelson and S.J. Elliott, also published by Academic Press. It summarizes the principles underlying active vibration control and its practical applications by combining material from vibrations, mechanics, signal processing, acoustics, and control theory. The emphasis of the book is on the active control of waves in structures, the active isolation of vibrations, the use of distributed strain actuators and sensors, and the active control of structurally radiated sound. The feedforward control of deterministic disturbances, the active control of structural waves and the active isolation of vibrations are covered in detail, as well as the more conventional work on modal feedback. The principles of the transducers used as actuateors and sensors for such control strategies are also given an in-depth description. The reader will find particularly interesting the two chapters on the active control of sound radiation from structures: active structural acoustic control. The reason for controlling high frequency vibration is often to prevent sound radiation, and the principles and practical application of such techniques are presented here for both plates and cylinders. The volume is written in textbook style and is aimed at students, practicing engineers, and researchers.

Energy-Based Sound Source Localization with Low Power Consumption in Wireless Sensor Networks

Abstract: In this study, we show that the energy-based method of sound source localization can be successfully exploited for sound source localization under low power consumption conditions. Sound source localization is widely applied in battlefield environments where low power consumption is especially crucial and necessary for extending the lifespan of sensor nodes. We propose several variables that may (possibly) affect the path loss exponent. We provide data that shows that energy-based methods of sound source localization can accurately determine the appropriate path loss exponent and can improve localization accuracy. The results of our study also demonstrate that energy-based methods of sound source localization can significantly reduce localization errors by adjusting sensors’ weight coefficients when ambient (background) noise exists. Our test results indicate that our method of source localization using low power consumption is consistently accurate and is able to determine sound source localization multiple times over an extended period.

Controllability-oriented placement of actuators for active noise-vibration control of rectangular plates using a memetic algorithm

Abstract: For successful active control with a vibrating plate it is essential to appropriately place actuators. One of the most important criteria is to make the system controllable, so any control objectives can be achieved. In this paper the controllability-oriented placement of actuators is undertaken. First, a theoretical model of a fully clamped rectangular plate is obtained. Optimization criterion based on maximization of controllability of the system is developed. The memetic algorithm is used to find the optimal solution. Obtained results are compared with those obtained by the evolutionary algorithm. The configuration is also validated experimentally.

Piezoelectric self sensing actuators for high voltage excitation

Abstract: Self sensing techniques allow the use of a piezoelectric transducer simultaneously as an actuator and as a sensor. Such techniques are based on knowledge of the transducer behaviour and on measurements of electrical quantities, in particular voltage and charge. Past research work has mainly considered the linear behaviour of piezoelectric transducers, consequently restricting the operating driving voltages to low values. In this work a new self sensing technique is proposed which is able to perform self sensing reconstruction both at low and at high driving voltages. This technique, in fact, makes use of a hysteretic model to describe the nonlinear piezoelectric capacitance necessary for self sensing reconstruction. The capacitance can be measured and identified at the antiresonances of a vibrating structure with a good approximation. After providing a mathematical background to deal with the main aspects of self sensing, this technique is compared theoretically and experimentally to a typical linear one by using an aluminum plate with one bonded self sensing transducer and a positive position feedback (PPF) controller to verify the performance in self sensing based vibration control.