Marek Kokot, Ph.D., Eng.


Doctoral thesis
2011-06-30Damage identification in electrical network for structural health monitoring 
supervisor -- Prof. Jan Holnicki-Szulc, Ph.D., Dr. Habil., Eng., IPPT PAN
642
 
Recent publications
1.Olaszek P., Wyczałek I., Sala D., Kokot M., Świercz A., Monitoring of the static and dynamic displacements of railway bridges with the use of inertial sensors, SENSORS, ISSN: 1424-8220, DOI: 10.3390/s20102767, Vol.20, No.10, pp.2767-1-24, 2020
Abstract:

In the case of the monitoring of bridges, the determination of vertical displacements is one of the most important issues. A new measuring system has been developed and implemented for assessment of railway bridges based on measurements of the structural response to passing trains. The system uses inertial sensors: Inclinometers and accelerometers that do not need any referential points. The system records signals related to the passage of a train over a monitored bridge. The signals from inclinometers before the train's entry are used to determine the static movement. Integrated signals from inclinometers and accelerometers are used to determine dynamic displacements when the train goes through the bridge. Signals from inclinometers are used to determine the so-called "quasi-static" component of the displacement and signal from the accelerometer to determine the dynamic component. Field tests have been carried out on a viaduct along a high-speed railway line. Periodic comparative measurements are carried out using a Total Station to verify static measurements and using inductive sensors to verify dynamic measurements. Tests of the system carried out so far have proven its usefulness for monitoring bridges in a high-speed railway (up to 200 km/h) with high accuracy while determining dynamic displacements.

Keywords:

bridge monitoring, dynamic and static displacements, inertial sensors, total station, indirect measurement

Affiliations:
Olaszek P.-Instytut Badawczy Dróg i Mostów (PL)
Wyczałek I.-Poznan University of Technology (PL)
Sala D.-IPPT PAN
Kokot M.-IPPT PAN
Świercz A.-IPPT PAN
2.Kokot M., Holnicki-Szulc J., Defect identification in electrical circuits via the virtual distortion method. Part 1: steady-state case, JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, ISSN: 1045-389X, DOI: 10.1177/1045389X09337169, Vol.20, No.12, pp.1465-1473, 2009
Abstract:

Virtual Distortion Method, a numerical technique originally developed and applied to various optimization problems in structural mechanics, is adapted to DC/AC circuit analysis. Electro-mechanical analogies with discrete models of plain truss structures are utilized to introduce and implement the main concepts of the method. Simulation of conductance modifications in circuit elements by the equivalent set of virtual sources is a foundation of numerically effective algorithms enabling fast re-analysis and sensitivity analysis. Inverse problem of defect identification is discussed and solution based on distortion approach is provided.

Keywords:

optimization, embedded intelligence, structural health monitoring

Affiliations:
Kokot M.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
3.Kokot M., Holnicki-Szulc J., Health monitoring of electric circuits, KEY ENGINEERING MATERIALS, ISSN: 1662-9795, DOI: 10.4028/www.scientific.net/KEM.293-294.669, Vol.293-294, pp.669-676, 2005
Abstract:

A methodology of defect identification in linear DC circuits based on so called Virtual Distortion Method (VDM) will be presented. The proposed approach takes adventage of the analogy linking mechanical models of truss structures and electric circuits. In this paper we cover the issue of modelling defects in electric circuits by compatible state of distortions, next we introduce the concept of influence matrix Dij, which describes global sensitivity of the circuit and enables fast recalculation of system response, and we formulate a gradient method of defect identification (inverse problem) based on local current and voltage measurements. In the following analysis we focus on so-called impotent states of distortions, which are the source of ambiguity of solution. We show that these difficulties can be overcome by a proper measuring strategy.

Keywords:

Defect Identification, Electric Circuits Monitoring, Inverse Problem

Affiliations:
Kokot M.-other affiliation
Holnicki-Szulc J.-IPPT PAN

List of chapters in recent monographs
1.
363
Holnicki-Szulc J., Kokot M., Kołakowski P., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: System identyfikacji spękań w konstrukcjach betonowy, IPPT Reports on Fundamental Technological Research, pp.160-188, 2014
2.
201
Kołakowski P., Świercz A., Orłowska A., Kokot M., Holnicki-Szulc J., Smart technologies for safety engineering, rozdział: VDM-Based health monitoring of engineering systems, Wiley, Holnicki-Szulc J. (Ed.), pp.37-103, 2008

Conference papers
1.Olaszek P., Świercz A., Sala D., Kokot M., System monitorowania łukowego wiaduktu kolejowego na linii wysokiej prędkości, WDM'17, WROCŁAWSKIE DNI MOSTOWE - Mosty. Przemiany w projektowaniu i technologiach budowy, 2017-11-28/11-29, Wrocław (PL), pp.481-488, 2017
Abstract:

The article presents the railway bridge structures monitoring system, which takes advantage of the dynamic response measurement and evaluation method. The monitoring system is focused on steel structures with the spans exceeding 30 m. The elaboration of the method which uses inclinometers together with an accelerometer for indirect displacement measurement under the dynamic load is the main achievement of the project.

Keywords:

monitoring, railway bridges, inclinometer, accelerometer

Affiliations:
Olaszek P.-Instytut Badawczy Dróg i Mostów (PL)
Świercz A.-IPPT PAN
Sala D.-other affiliation
Kokot M.-other affiliation

Patents
Filing No./Date
Filing Publication
Autor(s)
Title
Protection Area, Applicant Name
Patent Number
Date of Grant
pdf
390193
2010-01-28
BUP 16/11
2011-08-01
Kokot M., Holnicki-Szulc J.
Sposób monitorowania uszkodzeń w elementach konstrukcji i czujnik uszkodzeń w elementach konstrukcji
PL, Adaptronica Sp. z o.o.
217993
WUP 09/14
2014-09-30