Andrzej Świercz, Ph.D., Eng.

Department of Intelligent Technologies (ZTI)
Division of Safety Engineering (PIB)
position: main specialist
telephone: (+48) 22 826 12 81 ext.: 103
room: 431
e-mail: aswiercz

Doctoral thesis
2008-06-05Identyfikacja defektów w konstrukcjach prętowych na podstawie metody dystorsji wirtualnych w domenie częstości 
supervisor -- Prof. Jan Holnicki-Szulc, Ph.D., Dr. Habil., Eng., IPPT PAN
615
 
Recent publications
1.Błachowski B., Świercz A., Ostrowski M., Tauzowski P., Olaszek P., Jankowski Ł., Convex relaxation for efficient sensor layout optimization in large‐scale structures subjected to moving loads, Computer-Aided Civil and Infrastructure Engineering, ISSN: 1093-9687, DOI: 10.1111/mice.12553, pp.1-16, 2020
Abstract:

This paper proposes a computationally effective framework for load‐dependent optimal sensor placement in large‐scale civil engineering structures subjected to moving loads. Two common problems are addressed: selection of modes to be monitored and computational effectiveness. Typical sensor placement methods assume that the set of modes to be monitored is known. In practice, determination of such modes of interest is not straightforward. A practical approach is proposed that facilitates the selection of modes in a quasi‐automatic way based on the structural response at the candidate sensor locations to typical operational loads. The criterion used to assess sensor placement is based on Kammer's Effective Independence (EFI). However, in contrast to typical implementations of EFI, which treat the problem as a computationally demanding discrete problem and use greedy optimization, an approach based on convex relaxation is proposed. A notion of sensor density is applied, which converts the original combinatorial problem into a computationally tractable continuous optimization problem. The proposed framework is tested in application to a real tied‐arch railway bridge located in central Poland.

Keywords:

optimal sensor placement, effective independence method, Fisher information matrix

Affiliations:
Błachowski B.-IPPT PAN
Świercz A.-IPPT PAN
Ostrowski M.-IPPT PAN
Tauzowski P.-IPPT PAN
Olaszek P.-Instytut Badawczy Dróg i Mostów (PL)
Jankowski Ł.-IPPT PAN
2.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
3.Błachowski B., Ostrowski M., Tauzowski P., Świercz A., Jankowski Ł., Sensor placement for structural damage identification by means of topology optimization, AIP Conference Proceedings, ISSN: 0094-243X, DOI: 10.1063/5.0007817, Vol.2239, No.1, pp.020002-1-11, 2020
Abstract:

The success of virtually all structural health monitoring (SHM) methods depends on the information content of the measurements, and thus on the placement of the available sensors. This paper presents an efficient method for finding optimal sensor distribution over structural system with many degrees of freedom (DOFs). The objective function is based on the classical Fisher information matrix. Originally, this yields a computationally hard discrete optimization problem. However, the proposed numerical solution method is based on a concept taken from structural topology optimization, where a discrete optimization problem is replaced with a continuous one. Two numerical examples demonstrate the effectiveness of the proposed methodology. These are a 5-bay truss with 24 DOFs and a two-story frame structure whose finite element model has been condensed to 14 DOFs.

Keywords:

optimal sensor placement, structural damage identification, topology optimization

Affiliations:
Błachowski B.-IPPT PAN
Ostrowski M.-IPPT PAN
Tauzowski P.-IPPT PAN
Świercz A.-IPPT PAN
Jankowski Ł.-IPPT PAN
4.Olaszek P., Świercz A., Wyczałek I., Kołakowski P., Szadkowski K., Moduł pomiaru i oceny odpowiedzi eksploatowanych kolejowych konstrukcji mostowych, Mosty, ISSN: 1896-7663, Vol.3-4, pp.22-26, 2017
5.Pnevmatikos N.G., Błachowski B., Hatzigeorgiou G.D., Świercz A., Wavelet analysis based damage localization in steel frames with bolted connections, SMART STRUCTURES AND SYSTEMS, ISSN: 1738-1584, DOI: 10.12989/sss.2016.18.6.1189, Vol.18, No.6, pp.1189-1202, 2016
Abstract:

This paper describes an application of wavelet analysis for damage detection of a steel frame structure with bolted connections. The wavelet coefficients of the acceleration response for the healthy and loosened connection structure were calculated at each measurement point. The difference of the wavelet coefficients of the response of the healthy and loosened connection structure is selected as an indicator of the damage. At each node of structure the norm of the difference of the wavelet coefficients matrix is then calculated. The point for which the norm has the higher value is a candidate for location of the damage. The above procedure was experimentally verified on a laboratory-scale 2-meter-long steel frame. The structure consists of 11 steel beams forming a four-bay frame, which is subjected to impact loads using a modal hammer. The accelerations are measured at 20 different locations on the frame, including joints and beam elements. Two states of the structure are considered: healthy and damaged one. The damage is introduced by means of loosening two out of three bolts at one of the frame connections. Calculating the norm of the difference of the wavelet coefficients matrix at each node the higher value was found to be at the same location where the bolts were loosened. The presented experiment showed the effectiveness of the wavelet approach to damage detection of frame structures assembled using bolted connections.

Keywords:

complex bolted lap connection, frame structure, wavelet analysis, damage detection

Affiliations:
Pnevmatikos N.G.-Technological Educational Institute Athens (GR)
Błachowski B.-IPPT PAN
Hatzigeorgiou G.D.-Hellenic Open University (GR)
Świercz A.-IPPT PAN
6.Błachowski B., Świercz A., Gutkiewicz P., Szelążek J., Gutkowski W., Structural damage detectability using modal and ultrasonic approaches, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2016.02.033, Vol.85, pp.210-221, 2016
Abstract:

An experimental and analytical study of the relation between local defect, in a steel structure, and its higher frequencies and higher modes is discussed. The structure is a plane steel frame, assembled of beams, joined together with bolted connections. Removing some bolts from a given connection simulates the damage. In the experiment, an impulse force induced structural vibrations. Effects of vibrations were shown by data from gages, measuring accelerations with a high accuracy. From the data, it could be observed, that mode shapes, for the healthy and damaged structures didn’t show any differences for low frequencies. Only modes around thirteen showed significant gap between picks of Frequency Response Functions, for healthy and damaged frame. Moreover, looking at mode shapes, it could be observed that structural configuration may have some influence on defects to be observable. This aspect is discussed in a separate section. The experiment performed on the whole structure allows finding the place where the defect is localized. However, it can’t give detailed information on the defect itself, here defect of a bolt. For finding it, an ultrasonic measurement of pre-tensioning forces in bolts was applied. It allowed not only to determine stresses in the bolt, but also to verify, if in the process of assembling the structure was not pre-stressed.

Keywords:

Detectable damages, Bolted connections, Experimental modal analysis, Ultrasonic measurements, Steel frames, Analytical dynamics

Affiliations:
Błachowski B.-IPPT PAN
Świercz A.-IPPT PAN
Gutkiewicz P.-IPPT PAN
Szelążek J.-IPPT PAN
Gutkowski W.-other affiliation
7.Kołakowski P., Mróz A., Sala D., Pawłowski P., Sekuła K., Świercz A., Investigation of dynamic response of a railway bridge equipped with a tailored SHM system, KEY ENGINEERING MATERIALS, ISSN: 1662-9795, DOI: 10.4028/www.scientific.net/KEM.569-570.1068, Vol.569-570, pp.1068-1075, 2013
Abstract:

A railway bridge has been the object of investigation in the context of structural health monitoring (SHM). The current work is focused on utilization of experimental data for refining a numerical model of the structure as well as on tests of dynamic excitations using a controlled hydraulic shaker and passing trains. The numerical model has been matched to experimental measurements using experimental modal analysis - classical and operational. The tailored SHM system for monitoring of the bridge consists of 15 piezoelectric strain sensors taking advantage of wireless communication for data transfer. Experimental responses of the bridge collected by the SHM system are confronted with the ones produced by the FE numerical model of the bridge. The long-term objective of the investigation is to elaborate a method for assessment of structural condition and prediction of remaining lifetime of the bridge.

Keywords:

Bridge Monitoring, Experimental Measurements, Modal Analysis, Wireless SHM

Affiliations:
Kołakowski P.-other affiliation
Mróz A.-other affiliation
Sala D.-other affiliation
Pawłowski P.-IPPT PAN
Sekuła K.-other affiliation
Świercz A.-IPPT PAN
8.Sala D., Pawłowski P., Kołakowski P., Świercz A., Sekuła K., Monimost – Integrated SHM system for railway truss bridges, KEY ENGINEERING MATERIALS, ISSN: 1662-9795, Vol.518, pp.211-216, 2012
Abstract:

A railway bridge has been the object of investigation since mid 2007 as a response to increasing interest in structural health monitoring (SHM) from Polish Railways. It is a typical 40 m long, steel truss structure spanning a channel in Nieporet near Warsaw. There is over 1500 similar bridges in the railway network in Poland. The integrated system consists of two components – weigh in motion (WIM) part for identification of train load and SHM part for assessing the state of the bridge. Two aspects of wireless transmission are considered – short range (in the vicinity of the bridge, 2.4GHz) and far range (from the bridge to the data analysis center, GSM). The system is designed to be energetically self-sufficient, batteries are recharged by solar panels. Both the subsystems use piezoelectric strain sensors. Numerical model of the bridge corresponds well to the experimental data and provides a good starting point for considering different scenarios of simulated damage in the structure.

Keywords:

SHM, Piezo sensors, Wireless transmission, Bridge dynamics, Railway infrastructure

Affiliations:
Sala D.-IPPT PAN
Pawłowski P.-IPPT PAN
Kołakowski P.-other affiliation
Świercz A.-IPPT PAN
Sekuła K.-other affiliation
9.Sekuła K., Świercz A., Weigh-in-Motion System Testing, KEY ENGINEERING MATERIALS, ISSN: 1662-9795, Vol.518, pp.428-436, 2012
Abstract:

The paper presents some results of research on the Weight-in-motion (WIM) system. The device is used for identification of loads on the road surface generated by traveling vehicles. The proposed approach utilizes the piezoelectric measurement techniques to monitor strain development in a deformable body and eventually these measurements are used for tire- pavement load identification. An advantage of the proposed concept is that no additional limitation for a vehicle velocity and direction is required in order to make the measurement feasible. The device allow to identify many parameters which can be stored for statistical and planning purposes. When an overload or an exceed in speed limit is detected the data can be sent for penalization purposes. The research includes a computer simulation of the bending plate detector using the Finite Element Method (FEM). Its objective is to validate the concept as well as to test some factors which are important with respect to the proposed load identification methodology. An experimental research involved field tests on the WIM system using a bending plate detector and inductive loops to detect a vehicle.

Keywords:

Weigh-in-Motion, Load identification, Piezoelectric sensors, Sensitivity analysis

Affiliations:
Sekuła K.-IPPT PAN
Świercz A.-IPPT PAN
10.Kołakowski P., Szelążek J., Sekuła K., Świercz A., Mizerski K., Gutkiewicz P., Structural health monitoring of a railway truss bridge using vibration-based and ultrasonic methods, SMART MATERIALS AND STRUCTURES, ISSN: 0964-1726, Vol.20, No.3, pp.1-17, 2011
Abstract:

This paper presents results of in situ investigation of a railway truss bridge in the context of structural health monitoring (SHM). Three experimental methods are examined. Dynamic responses of the bridge recorded by strain gauges are confronted with alternative ways of acquisition using piezoelectric patch sensors and ultrasonic probeheads. All types of sensors produce similar output. Also the corresponding responses of the numerical model of the bridge match experimental data.

Affiliations:
Kołakowski P.-IPPT PAN
Szelążek J.-IPPT PAN
Sekuła K.-IPPT PAN
Świercz A.-IPPT PAN
Mizerski K.-IPPT PAN
Gutkiewicz P.-IPPT PAN
11.Świercz A., Kołakowski P., Holnicki-Szulc J., Damage identification in skeletal structures using the virtual distortion method in frequency domain, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2008.03.009, Vol.22, No.8, pp.1826-1839, 2008
Abstract:

The paper is a continuation of research on the application of a structural reanalysis method—the virtual distortion method—to structural health monitoring. The first approach, formulated previously in the time domain, suffered from a considerable numerical cost. In order to reduce it, this paper presents an alternative approach, formulated in the frequency domain thanks to the assumption of using harmonic excitation (quasi-static problem). The hardware devices supposed to collect structural responses are piezoelectric patch sensors. The software tool for damage identification solves a nonlinear least squares optimization problem by employing analytically derived sensitivities. Strains are the analyzed quantities, contributing to the objective function. Considerations are restricted to skeletal structures and a simplified dynamic problem with no damping. Effectiveness of the frequency-domain identification is demonstrated in numerical examples. Experimental verification is envisaged.

Keywords:

Damage identification, Inverse problem, Frequency domain, Skeletal structures, Reanalysis methods

Affiliations:
Świercz A.-IPPT PAN
Kołakowski P.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
12.Świercz A., Kołakowski P., Holnicki-Szulc J., Structural damage identification using low frequency non-resonance harmonic excitation, KEY ENGINEERING MATERIALS, ISSN: 1662-9795, DOI: 10.4028/www.scientific.net/KEM.347.427, Vol.347, pp.427-432, 2007
Keywords:

Frequency-Based Analysis, Inverse Problem, Piezo Devices, Structural Damage Identification

Affiliations:
Świercz A.-IPPT PAN
Kołakowski P.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN

List of chapters in recent monographs
1.
349
Jankowski Ł., Holnicki-Szulc J., Świercz A., Mróz M., Kołakowski P., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: Numeryczne metody identyfikacji parametrów konstrukcji, IPPT Reports on Fundamental Technological Research, pp.109-159, 2014
2.
361
Kołakowski P., Pawłowski P., Sala D., Sekuła K., Świercz A., Wiącek D., Wójcicki P., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: Dynamiczna waga kolejowa, IPPT Reports on Fundamental Technological Research, pp.55-84, 2014
3.
360
Sekuła K., Pawłowski P., Sala D., Kołakowski P., Świercz A., Wiącek D., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: Dynamiczna waga drogowa, IPPT Reports on Fundamental Technological Research, pp.21-54, 2014
4.
362
Kołakowski P., Mróz A., Orłowska A., Pawłowski P., Sala D., Sekuła K., Świercz A., Wiącek D., Wójcicki P., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: System monitorowania stalowego mostu kolejowego, IPPT Reports on Fundamental Technological Research, pp.85-108, 2014
5.
364
Graczykowski C., Knor G., Kołakowski P., Mikułowski G., Orłowska A., Pawłowski P., Skłodowski M., Świercz A., Wiszowaty R., Zieliński T.G., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: Wybrane zagadnienia monitorowania, IPPT Reports on Fundamental Technological Research, pp.189-236, 2014
6.
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.Błachowski B., Tauzowski P., Świercz A., Jankowski Ł., Topology optimization approach for dense sensor network distribution over large bridge structures, SMART 2019, 9th ECCOMAS Thematic Conference on Smart Structures and Materials, 2019-07-08/07-11, Paris (FR), pp.284-290, 2019
Abstract:

Recent progress in sensing technology and measurement techniques allows a growing number of critical infrastructures to be equipped with Structural Health Monitoring (SHM) systems. Sensors in such SHM systems should be placed in a proper way to facilitate extracting valuable information from the structure under investigation. In the case of relatively simple spatial truss structures, sensors can be located with the aid of classical methods such as Effective Independence (EI) method proposed by Kammer. However, in the case of large structures, which are intended to be equipped with hundreds if not thousands of sensors, other sensor placement methods may be needed.
The goal of this study is to extend a topology optimization based approach for sensor placement (proposed originally by Mariani and co-workers) to the case of real bridge structures represented by finite element models with a few thousand degrees of freedom. Structural topology optimization aims to find the optimum material distribution in order to minimize the mass of the structure while maintaining mechanical properties (load capacity, displacements, etc.). A similar concept can be used to determine the optimal placement of sensors in a structure to identify its dynamic characteristics. The sensor positions are determined in such a way that estimation error of modal coordinates is minimized. The effectiveness of the proposed methodology is demonstrated on an example of a detailed FE model of a tied-arch bridge.

Keywords:

Optimal sensor placement, Structural parameter identification, Topology optimization

Affiliations:
Błachowski B.-IPPT PAN
Tauzowski P.-IPPT PAN
Świercz A.-IPPT PAN
Jankowski Ł.-IPPT PAN
2.Świercz A., Holnicki-Szulc J., Ultra-light, self-deployable, rod-cable structures, SMART 2019, 9th ECCOMAS Thematic Conference on Smart Structures and Materials, 2019-07-08/07-11, Paris (FR), pp.537-542, 2019
Abstract:

This article is devoted to space truss-like structures commonly used for solar panel installations or telecommunication antennas. Such structures have obvious advantage of beneficial ratio of their stiffness to mass. One of challenges in satellite engineering is focused on special design of ultra-light structures, compacted during transportation to the orbit, able to deploy into large cantilever with e.g. photovoltaic panels (being on the orbit). This approach allows for better withstands the launch loads in compact configuration. The proposed smart topology (SMARTOP) of the structure enables for easy, zero-energetic transformation from the compact, two-dimensional form into the final, tree-dimensional configuration, making use of stored pre-stress energy, released with use of specially controlled clutches. Main innovations are in specially design topology and so-called smart clutches performing controlled release of stored strain energy in a proper timing. Numerical simulations of the SMARTOP structure functionalities are presented.

Keywords:

self-deployable structures, prestressed truss-like structures, rod-cable structures, joint connections, vibration reduction

Affiliations:
Świercz A.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
3.Błachowski B., Świercz A., Jankowski Ł., Virtual Distortion Method based optimal sensor placement for damage identification, ISMA 2018 / USD 2018, International Conference on Noise and Vibration Engineering / International Conference on Uncertainty in Structural Dynamics, 2018-09-17/09-19, Leuven (BE), pp.3815-3824, 2018
Abstract:

The paper presents a novel method for sensor placement optimized towards effective identification of structural damages. The derivation of the method is based on the concept of virtual distortions together with information provided by a set of strain gauges. Then, a gradient oriented optimization is applied to identify sensor locations, which are the most sensitive to potential damage scenarios. Steepest descent method is utilized to determine the optimal values of the objective function. Additionally, dependence of the method on the applied excitation signal is discussed. Finally, effectiveness of the proposed methodology is demonstrated on an example of optimal search for sensor placement on a 6-bay planar truss structure.

Keywords:

optimal sensor placement, virtual distortion method, damage identification

Affiliations:
Błachowski B.-IPPT PAN
Świercz A.-IPPT PAN
Jankowski Ł.-IPPT PAN
4.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
5.Błachowski B., Świercz A., Pnevmatikos N., Experimental verification of damage location techniques for frame structures assembled using bolted connections, COMPDYN 2015, 5th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, 2015-05-25/05-27, Crete Island (GR), pp.C1511-1-12, 2015
Abstract:

This work is focused on experimental verification of existing techniques for localization of a loosened bolted connection. To this end, a laboratory-scale 2-meter-long steel frame is used. The structure consists of 11 steel beams forming a four-bay frame, which is subjected to impact loads using a modal hammer. The accelerations are measured at 20 different locations on the frame, including joints and beam elements. Two states of the structure are considered: a healthy and a damaged one. The damage is introduced by means of loosening two out of three bolts at one of the frame connections. Experimental modal analysis reveals that the loosened bolts in the connection cause a shift only in some of the frame’s natural frequencies, while the others remain insensitive to the damage.

Keywords:

bolted lap connection, frame structure, experimental modal analysis, damage location

Affiliations:
Błachowski B.-IPPT PAN
Świercz A.-IPPT PAN
Pnevmatikos N.-Technological Educational Institute Athens (GR)
6.Świercz A., Holnicki-Szulc J., Kołakowski P., Impact loads for structural damage identification, 7th European Workshop on Structural Health Monitoring, 2014-07-08/07-11, Nantes (FR), pp.2115-2122, 2014
Abstract:

In this paper we numerically study simple two dimensional frame structure loaded by impulse-like excitations. Various configurations of time duration of a single impact load and location of this excitation are investigated. The aim of this research is to indicate the best possible load case for identification of a specific damage. Two kinds of structural modifications are considered. The first group concerns the element stiffness changes (axial and bending) which can be simulated by alternating the Young‘s modulus. The second group covers the modifications of stiffness nodal connections. In a numerical model, these kinds of defects can be implemented using rotational spring with different characteristics. Obtained selected responses for the original and modified structure are numerically generated.

Keywords:

structural modification, semi-rigid joint, virtual distortion method, gradient-based optimization

Affiliations:
Świercz A.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
Kołakowski P.-IPPT PAN
7.Świercz A., Kołakowski P., Holnicki-Szulc J., Olkowicz D., Identification of semi-rigid joints in frame structures, SMART2013, 6th ECCOMAS Thematic Conference on Smart Structures and Materials, 2013-09-03/09-06, Turyn (IT), pp.1-12, 2013
Abstract:

This study presents the numerical analysis and experimental tests of a planar frame structure with semi-rigid joints. Based on structural responses the identification of nodal parameters is performed.

Keywords:

Frame structures, Semi-rigid joints, Inverse problem, SHM

Affiliations:
Świercz A.-IPPT PAN
Kołakowski P.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
Olkowicz D.-IPPT PAN
8.Świercz A., Kołakowski P., Holnicki-Szulc J., Impact-Load-Based Damage Identification in Joints of Skeletal Structures, EWSHM 2012, 6th European workshop on Structural Health Monitoring, 2012-07-03/07-06, Dresden (GE), Vol.1, pp.841-848, 2012
Abstract:

The nodal connections in the standard analysis of frame structures are idealized assuming either pinned or fully rigid joints. State of such structural connections is highly important for safe operation of skeletal structures. In this work, the authors propose modeling, detection and identification of semi-rigid joints, i.e. nodal connections covering the range between pinned and fully rigid joints. The presented approach is based on the Virtual Distortion Method (VDM) and dedicated to statically or dynamically loaded two-dimensional frame structures.

Affiliations:
Świercz A.-IPPT PAN
Kołakowski P.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
9.Kołakowski P., Sekuła K., Pawłowski P., Sala D., Świercz A., Monitoring of Railway Traffic as a Part of Integrated SHM System, EWSHM 2012, 6th European workshop on Structural Health Monitoring, 2012-07-03/07-06, Dresden (GE), Vol.2, pp.1395-1400, 2012
Abstract:

In the last years one can observe an increasing interest in structural health monitoring (SHM) from Polish Railways. There are several hundreds of steel truss bridges of various spans and similar topologies in Polish railway infrastructure. One of them, located over a canal in Nieporęt near Warsaw with span of 40m became an object of investigation and implementation of an integrated SHM system. The system consists of two components – weigh in motion (WIM) part for identification of train load and SHM part for assessing the bridge state. The WIM module supplies load data required for SHM inverse analyses, however it can operate as an independent system for monitoring of railway traffic providing information about axle loads and rolling stock identification. Many in-situ installations of SHM systems suffer from a troublesome and time- consuming way of data acquisition via standard cables. In order to facilitate data collection related with this way of acquisition, an alternative solution of wireless transmission of the measured data from the field to analysis centre is proposed. Two aspects of wireless transmission are considered – short range (in the vicinity of the bridge) and far range (from the bridge to the centre of analysis). This paper takes up the practical issue of design and implementation of the integrated SHM system for truss steel railway bridge with a special insight into the monitoring of railway traffic.

Keywords:

Structural Health Monitoring, monitoring of steel railway bridges

Affiliations:
Kołakowski P.-IPPT PAN
Sekuła K.-other affiliation
Pawłowski P.-IPPT PAN
Sala D.-IPPT PAN
Świercz A.-IPPT PAN
10.Świercz A., Kołakowski P., Holnicki-Szulc J., Monitoring of progressive collapse of skeletal structures, DAMAS, 9th International Conference on Damage Assessment of Structures, 2011-07-11/07-13, Oxford (GB), DOI: 10.1088/1742-6596/305/1/012133, Vol.305, No.1, pp.012133-1-8, 2011
Abstract:

The authors propose an idea of monitoring the state of skeletal structures of high importance (e.g. roof structures over large area buildings) with the aim of identification of slowly-developing plastic zones. This is formulated as an inverse problem within the framework of the Virtual Distortion Method, which was used previously to identify stiffness/mass modifications in similar manner. Permanent plastic strains developed in a truss element can be modeled by an initial strain (virtual distortion) introduced to the structure. The formation of subsequent plastic zones in the structure is assumed to be slow. Consequently, the design variable (plastic strain) is time-independent, which makes the inverse analysis efficient. This article presents problem formulation and numerical algorithm for identification of the plastic strains in truss structures. The identification relies on gradient-based optimization. A numerical example is included to demonstrate the efficiency of the algorithm.

Affiliations:
Świercz A.-IPPT PAN
Kołakowski P.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
11.Kołakowski P., Sala D., Pawłowski P., Świercz A., Sekuła K., Implementation of SHM system for a railway truss bridge, EURODYN 2011, 8th International Conference on Structural Dynamics, 2011-07-04/07-06, Leuven (BE), pp.1-5, 2011
Abstract:

In the last years one can observe an increasing interest in structural health monitoring (SHM) from Polish Railways. There are several hundreds of steel truss bridges of various spans and similar topologies in Polish railway infrastructure. One of them, located over a canal in Nieporęt near Warsaw with span of 40m became an object of investigation and implementation of an integrated SHM system.
The system consists of two components – weigh in motion (WIM) part for identification of train load and SHM part for assessing the bridge state. The WIM module supplies load data required for SHM inverse analyses, however it can operate as an independent system for monitoring of railway traffic providing information about axle loads and rolling stock identification.
Many in-situ installations of SHM systems suffer from a troublesome and time-consuming way of data acquisition via standard cables. In order to facilitate data collection related with this way of acquisition, an alternative solution of wireless transmission of the measured data from the field to analysis centre is proposed. Two aspects of wireless transmission are considered – short range (in the vicinity of the bridge) and far range (from the bridge to the centre of analysis).
This paper takes up the practical issue of design and implementation of the integrated SHM system for truss steel railway bridge with a special insight into the monitoring of railway traffic.

Keywords:

SHM systems, monitoring of railway bridges

Affiliations:
Kołakowski P.-IPPT PAN
Sala D.-IPPT PAN
Pawłowski P.-IPPT PAN
Świercz A.-IPPT PAN
Sekuła K.-IPPT PAN
12.Świercz A., Kołakowski P., Holnicki-Szulc J., Damage identification in structural joints using the Virtual Distortion Method, SMART2011, 5th ECCOMAS Thematic Conference on Smart Structures and Materials, 2011-07-06/07-08, Saarbrücken (DE), pp.1-6, 2011
13.Kołakowski P., Szelążek J., Sekuła K., Świercz A., Structural health monitoring of a railway truss bridge using low- and high-frequency methods, 11th Workshop on Smart Diagnostics of Structures, 2010-10-18/10-20, Kraków (PL), pp.1-8, 2010
Abstract:

The paper presents results of in-situ investigation of a railway truss bridge in the context of SHM. Three experimental methods are examined. Dynamic responses of the bridge recorded by strain gauges are confronted with alternative ways of acquisition using piezoelectric sensors and ultrasonic probeheads. Numerical model corresponds to experimental data.

Affiliations:
Kołakowski P.-IPPT PAN
Szelążek J.-IPPT PAN
Sekuła K.-IPPT PAN
Świercz A.-IPPT PAN
14.Świercz A., Kołakowski P., Holnicki-Szulc J., Sensitivity-based Structural Health Monitoring of Skeletal Structures, 11th Workshop on Smart Diagnostics of Structures, 2010-10-18/10-20, Kraków (PL), pp.1-8, 2010
15.Świercz A., Kołakowski P., Holnicki-Szulc J., Monitorowanie postępującego rozwoju stref plastycznych w konstrukcjach szkieletowych, 56 Konferencja Naukowa KILiW PAN i KN PZITB, 2010-09-19/09-24, Kielce-Krynica (PL), pp.1-11, 2010
16.Malesa M., Szczepanek D., Kujawińska M., Świercz A., Kołakowski P., Monitoring of civil engineering structures using Digital Image Correlation technique, ICEM 14, 14th International Conference on Experimental Mechanics, 2010-07-04/07-09, Poitiers (FR), pp.1-8, 2010
17.Sekuła K., Kołakowski P., Świercz A., System monitorowania obciążeń oraz stanu technicznego kratownicowych mostów w kolejnictwie, Seminarium Monitorowanie Stanu Technicznego Konstrukcji i Ocena Jej Żywotności, 2010-11-19/11-19, Warszawa (PL), pp.1-4, 2010
18.Kołakowski P., Jankowski Ł., Świercz A., Wikło M., Time-domain identification of damage in skeletal structures using strain measurements and gradient-based optimization, ISMA 2008, International Conference on Noise and Vibration Engineering, 2008-09-15/09-17, Louvain (BE), pp.3257-3266, 2008
Abstract:

This paper presents an improved numerical tool for identification of damage in skeletal structures. The problem of identification has been formulated in the time domain within the framework of the Virtual Distortion Method (VDM). VDM generally belongs to fast structural reanalysis methods and can be applied to Structural Health Monitoring problems, among others. The major computational asset of VDM is the influence matrix, containing all the local-global inter-relations for a structure due to given perturbations e.g. initial strain or external force. A non-linear least squares problem with strains, entering the objective function, is the subject of consideration. Strains are used in order to have relatively smooth variations (compared to accelerations) of the analyzed signal in time. The change of stiffness is the design variable. Analytical gradients are implemented in the optimization code based on the Levenberg-Marquardt algorithm with some penalty function terms. The efficiency of the software tool is demonstrated for a numerical example of a 2D truss structure. A breakthrough in terms of computational time reduction has been observed compared to the previously used steepest-descent optimization. The presented software assumes the feasibility of reliable measurements of strains in time for real skeletal structures (e.g. truss bridges). Future research will include experimental verification of the idea with piezoelectric sensors acting as tensometers.

Affiliations:
Kołakowski P.-IPPT PAN
Jankowski Ł.-IPPT PAN
Świercz A.-IPPT PAN
Wikło M.-IPPT PAN

Conference abstracts
1.Błachowski B., Tauzowski P., Świercz A., Jankowski Ł., Sensor placement for structural damage identification by means of topology optimization, PCM-CMM, 4th Polish Congress of Mechanics, 23rd International Conference on Computer Methods in Mechanics, 2019-09-08/09-12, Kraków (PL), pp.1, 2019
Abstract:

Damage identification attracted a lot of attention during the last three decades. The reason for that is the fact that large number of existing civil infrastructures reached their service life and growing number of structures is equipped with Structural Health Monitoring (SHM) systems. A successful structural damage identification is determined by three inseparably coupled factors: sensor placement, damage location and its extend, and finally location and time-frequency characteristics of the applied excitation. The purpose of this study is to address the first of the mentioned aspects, namely optimal sensor placement. A vast literature has been devoted to optimal sensor placement methods among which Effective Independence (EI) method proposed by Kammer and Tinker is one of the most successfully applied in practice. However, EI method is dedicated rather to test-analysis correlation and therefore more specific methods for damage identification are still needed. Additionally, in the case of large civil structures, which are intended to be equipped with large amount of sensors of different type, other sensor placement methods can be more efficient. Recently, a promising idea of utilizing a topology optimization approach for the purpose of sensor placement has been proposed by Bruggi and Mariani. The goal of this study is to extend their method, which has been verified on a plate structure, to the case of a FE model of a real arch bridge structure consisting a few thousands degrees of freedom. The main purpose of this work is to find the optimal arrangement of sensors on the structure to detect defects most accurately. The objective function for the problem formulated in this way is the total, weighted difference between the deformation of a damaged and undamaged state. This problem is very similar to the topological optimization, where we search for the optimal material distribution minimizing the mass of the structure while meeting the conditions related to some mechanical properties such as the maximum displacement of the structure, stress intensity or load capacity. This similarity led us to apply topological optimization to the problem of optimal placement of damage sensors. Several numerical examples prove the applicability of topological optimization for optimal sensor placement problem.

Keywords:

Sensor Placement, Damage Identification, Topology Optimization

Affiliations:
Błachowski B.-IPPT PAN
Tauzowski P.-IPPT PAN
Świercz A.-IPPT PAN
Jankowski Ł.-IPPT PAN
2.Ostrowski M., Świercz A., Błachowski B., Tauzowski P., Jankowski Ł., Optimization of Sensor Placement Using Continuous Approaches, WEO2019, Workshop on Engineering Optimization 2019, 2019-11-04/11-04, Warszawa (PL), pp.22-23, 2019
Abstract:

The present study provides a comprehensive framework for sensor layout optimization aiming at accurate estimation of the modal coordinates coming from the structural response. The proposed procedure consists of two steps briefly described below. The first step is a selection of vibrational modes taking part in the motion of structures during their normal operation – in this case subjected to traveling load. Among these structures there are various types of bridges especially railway bridges. In the case of present study structural responses are obtained from rigorous finite element (FE) model of the bridge. The FE model is calibrated with measured response of real bridge located in Huta Zawadzka. The calibration process is based on the displacement signals of the bridge under the traveling load. In the second step modes of interest are selected and a set of candidate sensor locations is proposed. It is a subset of all degrees of freedom (DOFs) of the FE model from which several locations are chosen as best possible locations for the displacement sensors. The above sensor placement problem is a combinatorial task. Many methods for solving such problems have been developed previously, but in the case of large scale structures they require tremendous computational effort. To reduce this effort the so-called convex relaxation is incorporated into optimization process. The technique consists in reformulation of combinatorial problem into continuous convex one. Then, the convex relaxation is achieved by introducing the so-called sensor density function, which assigns a certain metric for individual candidate sensor location. Next, the value of this function is optimized in such a way that it maximize determinant of the Fisher Information Matrix. It has been shown that above algorithm is very effective and is distributing a number of sensors in several iterations only. Finally, it is worth noting that presented method can be used to distribute sensors for structural health monitoring. Moreover, it can be also applied in modal control strategies in vibration suppression.

Affiliations:
Ostrowski M.-IPPT PAN
Świercz A.-IPPT PAN
Błachowski B.-IPPT PAN
Tauzowski P.-IPPT PAN
Jankowski Ł.-IPPT PAN

Patents
Filing No./Date
Filing Publication
Autor(s)
Title
Protection Area, Applicant Name
Patent Number
Date of Grant
pdf
430705
2019-07-24
-
-
Holnicki-Szulc J., Świercz A., Kostro S.
Koncepcja struktury SDT (Self-Deployable Tensegrity) wspomagającej szybkie i precyzyjne wynoszenie aerostatów helowych, w szczególności do stratosfery
PL, Instytut Podstawowych Problemów Techniki PAN, Adaptronica Sp. z o.o.
-
-
-
429902
2019-05-10
-
-
Holnicki-Szulc J., Świercz A., Knap L.
Samo-rozkładalna, cięgnowo-prętowa struktura wsporcza
PL, Instytut Podstawowych Problemów Techniki PAN, Adaptronica Sp. z o.o.
-
-
-
397310
2011-12-09
BUP 12/13
2013-06-10
Świercz A., Holnicki-Szulc J., Kołakowski P.
Sposób wyznaczania obciążeń w górotworze
PL, Instytut Podstawowych Problemów Techniki PAN, Adaptronica Sp. z o.o.
222132
WUP 07/16
2016-07-29



397312
2011-12-09
BUP 12/13
2013-06-10
Świercz A., Mikułowski G., Wiszowaty R., Holnicki-Szulc J., Kołakowski P., Graczykowski C.
Sposób generowania wstępnie zaprojektowanego udarowego obciażania konstrukcji oraz urzadzenie do generowania wstępnie zaprojektowanego obciążania konstrukcji
PL, Instytut Podstawowych Problemów Techniki PAN, Adaptronica Sp. z o.o.
221709
WUP 05/16
2016-05-31



387115
2009-01-24
BUP 16/10
2009-01-24
Kołakowski P., Sala D., Sekuła K., Świercz A.
Sposób monitorowania konstrukcji kratownicowej mostu i układ do monitorowania konstrukcji kratownicowej mostu
PL, Adaptronica Sp. z o.o.
218294
WUP 11/14
2014-11-28