Search

Your search keyword '"Ostachowicz, W."' showing total 292 results
Start Over Author "Ostachowicz, W."
292 results on '"Ostachowicz, W."'

2. Observation of a Lamb band gap in a polymer waveguide with periodic cross-like cavities

Author

Miniaci, M., Mazzotti, M., Radzieński, M., Kherraz, N., Kudela, P., Ostachowicz, W., Morvan, B., Bosia, F., and Pugno, N. M.

Subjects
Physics - Applied Physics
Abstract

The quest for large and low frequency band gaps is one of the principal objectives pursued in a number of engineering applications, ranging from noise absorption to vibration control, to seismic wave abatement. For this purpose, a plethora of complex architectures (including multi-phase materials) and multi-physics approaches have been proposed in the past, often involving difficulties in their practical realization. To address this issue, in this work we propose an easy-to-manufacture design able to open large, low frequency complete Lamb band gaps exploiting a suitable arrangement of masses and stiffnesses produced by cavities in a monolithic material. The performance of the designed structure is evaluated by numerical simulations and confirmed by Scanning Laser Doppler Vibrometer (SLDV) measurements on an isotropic polyvinyl chloride plate in which a square ring region of cross-like cavities is fabricated. The full wave field reconstruction clearly confirms the ability of even a limited number of unit cell rows of the proposed design to efficiently attenuate Lamb waves. In addition, numerical simulations show that the structure allows to shift of the central frequency of the BG through geometrical modifications. The design may be of interest for applications in which large BGs at low frequencies are required.

Published
2017

3. How Temperature Variations Affect the Propagation Behaviour of Guided Ultrasonic Waves in Different Materials

Author

Rennoch, M., Moll, J., Koerdt, M., Herrmann, A. S., Wandowski, T., Ostachowicz, W. M., Cavas-Martínez, Francisco, Series Editor, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Haddar, Mohamed, Series Editor, Ivanov, Vitalii, Series Editor, Kwon, Young W., Series Editor, Trojanowska, Justyna, Series Editor, Gelman, Len, editor, Martin, Nadine, editor, Malcolm, Andrew A., editor, and (Edmund) Liew, Chin Kian, editor

Published
2021
Full Text
View/download PDF

25. Dynamics of multilayered composite plates with shape memory alloy wires

Author

Zak, A.J., Cartmell, M.P., and Ostachowicz, W.

Subjects
Shape-memory alloys -- Research, Mechanics -- Research, Science and technology
Abstract

In this paper certain aspects of the dynamic behavior of a multilayered, composite plate with shape memory alloys (SMA) wires have been investigated. The influence of parameters such as the orientation and location of SMA wires, the orientation and relative volume fraction of reinforcing fibers, the thickness-to-length and length-to-width ratios, and different boundary conditions, on changes in the critical load, the natural frequencies and the modes of vibrations of the plate have all been studied and discussed in the paper. The use of two different techniques, generally known in the literature as the active property tuning and active strain energy tuning methods, has also been investigated. The results presented in this paper have been obtained by the use of the finite element method and a new finite element formulated for multilayered composite plates has been applied for this purpose. [DOI: 10.1115/1.1546263]

Published
2003

28. Natural vibrations of a clamped-clamped arch with an open transverse crack

Author

Krawczuk, M. and Ostachowicz, W.

Subjects
Materials -- Fatigue, Arches -- Models, Vibration -- Models, Science and technology
Abstract

The paper presents a finite element model of the arch with a transverse, one-edge crack. A part of the cracked arch is modelled by a curved beam finite element with the crack. Parts of the arch without the crack are modelled by noncracked curved beam finite elements. The crack occurring in the arch is nonpropagating and open. It is assumed that the crack changes only the stiffness of the arch, whereas the mass is unchanged. The method of the formation of the stiffness matrix of a curved beam finite element with the crack is presented. The effects of the crack location and its length on the changes of the in-plane natural frequencies and mode shapes of the clamped-clamped arch are studied.

Published
1997

43. Numerical and experimental analysis of membrane with piezoelectric element used for synthetic jet flow control

Author

Rimašauskienė, R., Rimašauskas, M., Jūrėnas, V., Ostachowicz, W., Matejka, M., Kauno technologijos universitetas, Lietuvos mokslų akademija, and Vilniaus Gedimino technikos universitetas

Subjects
Engineering, piezoelectricity, business.industry, Modal analysis, Airflow, Mechanical engineering, piezoelectric actuator, Condensed Matter Physics, Piezoelectricity, non-contact measurements, Flow control (fluid), Anemometer, Piezoelectric motor, Synthetic jet, synthetic jets, PMUT, business
Abstract

Synthetic jet generators have been widely ana-lysed in controlling the airflow of aircrafts aiming to en-hance aircraft lifting and manoeuvrability, control stalls, and reduce the noise level. One of the best choices is to use piezoelectric actuators in the design of such kind of the devices because of its favourable properties. This article presents a numerical and experimental modal analysis of the membrane with bonded piezoelectric element Sonox P502. The aim of this investigation was to find suitable piezoelectric actuator for controlling synthetic jet flow. And in order to check the suitability and reliability of the received data about the piezoelectric membrane, experi-mental analysis of the synthetic jet generator was per-formed. The CTA (Constant Temperature Anemometers) technique is very sensitive and was used for the determina-tion of frequencies and velocity of flow.DOI: http://dx.doi.org/10.5755/j01.mech.21.1.10130

Published
2015
Full Text
View/download PDF

47. Calibration Problem of AD5933 Device for Electromechanical Impedance Measurements

Author

Wandowski, T., Paweł Malinowski, Ostachowicz, W., Jaigu, Anne, Le Cam, Vincent and Mevel, Laurent and Schoefs, Franck, Szewalski Institute of Fluid-Flow Machinery [Gdańsk] (IMP), Polska Akademia Nauk = Polish Academy of Sciences (PAN), IFFSTTAR, Inria, Université de Nantes, Le Cam, Vincent and Mevel, Laurent and Schoefs, and Franck

Subjects
Signal processing, Piezoelectric sensors, [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], Damage detection and localization, [STAT.TH] Statistics [stat]/Statistics Theory [stat.TH], [PHYS.MECA]Physics [physics]/Mechanics [physics], [STAT.TH]Statistics [stat]/Statistics Theory [stat.TH], [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], [PHYS.MECA] Physics [physics]/Mechanics [physics], [SPI.MECA] Engineering Sciences [physics]/Mechanics [physics.med-ph], [MATH.MATH-ST] Mathematics [math]/Statistics [math.ST]
Abstract

International audience; In this paper influence of incorrect calibration of AD5933 electrical impedance analyzer on errors in measurements was investigated. AD5933 is developed in the form of electronic integrated circuit by the Analog Devices. This device is very popular in the field of Structural Health Monitoring based on electromechanical impedance method. Electromechanical impedance method relies on measurements of electrical impedance of piezoelectric transducer bonded to the structure. Due to electromechanical coupling of piezoelectric transducer mechanical resonances of the structure can be seen in the electrical impedance characteristics of piezoelectric transducer. In order to properly measure electrical impedance mentioned devices must be calibrated using calibration resistor. In this research influence of wrongly selected calibration resistor value on the measurement results was interrogated. Measurements conducted with AD5933 were compared with measurements realized using professional electrical impedance analyzer HIOKI IM3570. Research was related to simple supported beam made out of aluminium alloy with piezoelectric transducer in the form of disc. Measurements were taken for referential state as well as for few states with artificial introduced damage in the form of notch.

Published
2014

48. Detecting multiple small-sized damage in beam-type structures by Teager energy of modal curvature shape

Author

Xu, W., Cao, M. S., Radzieński, M., Xia, N., Su, Z., Ostachowicz, W., Wang, S. S., Xu, W., Cao, M. S., Radzieński, M., Xia, N., Su, Z., Ostachowicz, W., and Wang, S. S.

Abstract

Detection of multiple damage using modal curvature has become a research focus of great significance in recent years. Nevertheless, a noticeable deficiency of modal curvature is its inadequacy in identifying small-sized damage, which usually results in damage signatures being obscured by the global fluctuation trend of modal curvature. To address this deficiency, this study develops a damage feature of Teager energy of modal curvature shape to identify multiple small-sized damage against the global fluctuation trend of the modal curvature. The advantage of this damage feature over the traditional modal curvature in small-sized damage characterization is first verified in analytical cases of cracked beams with various types of boundary condition, and further validated in a cracked carbon-fiber-reinforced polymer composite beam with the mode shapes acquired using a scanning laser vibrometer.

Published
2015

49. Multiple damage detection in beams in noisy conditions using complex-wavelet modal curvature by laser measurement

Author

Xu, W., Cao, M. S., Radzieński, M., Ostachowicz, W., Xu, W., Cao, M. S., Radzieński, M., and Ostachowicz, W.

Abstract

Detection of multiple damage using modal curvature in noisy environments has become a research focus of considerable challenge and great significance over the last few years. However, a noticeable deficiency of modal curvature is its susceptibility to noise, which usually results in a noisy modal curvature with obscured damage signature. To address this deficiency, this study formulates a new concept of complex-wavelet modal curvature. Complex-wavelet modal curvature features the ability to reveal and delineate damage under noisy conditions. The effectiveness of the concept is experimentally validated in a carbon-fiber-reinforced polymer composite beam with three cracks, for which mode shapes are measured by a scanning laser vibrometer. The experimental results show that the complex-wavelet modal curvature is capable of revealing slight damage by eliminating noise interference, with no need for prior knowledge of either material properties or boundary conditions of the beam under inspection.

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results