Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk

Pracownicy

mgr inż. Mariusz Ostrowski

Zakład Technologii Inteligentnych (ZTI)
Pracownia Inżynierii Bezpieczeństwa (PIB)
stanowisko: specjalista
doktorant
telefon: (+48) 22 826 12 81 wewn.: 103
pokój: 431
e-mail:
ORCID: 0000-0003-2388-5203

Ostatnie publikacje
1.  Ostrowski M., Błachowski B., Mikułowski G., Jankowski Ł., Influence of Noise in Computer-Vision-Based Measurements on Parameter Identification in Structural Dynamics, SENSORS, ISSN: 1424-8220, DOI: 10.3390/s23010291, Vol.23, No.1, pp.1-27, 2023

Streszczenie:
Nowadays, consumer electronics offer computer-vision-based (CV) measurements of dynamic displacements with some trade-offs between sampling frequency, resolution and low cost of the device. This study considers a consumer-grade smartphone camera based on complementary metal-oxide semiconductor (CMOS) technology and investigates the influence of its hardware limitations on the estimation of dynamic displacements, modal parameters and stiffness parameters of bolted connections in a laboratory structure. An algorithm that maximizes the zero-normalized cross-correlation function is employed to extract the dynamic displacements. The modal parameters are identified with the stochastic subspace identification method. The stiffness parameters are identified using a model-updating technique based on modal sensitivities. The results are compared with the corresponding data obtained with accelerometers and a laser distance sensor. The CV measurement allows lower-order vibration modes to be identified with a systematic (bias) error that is nearly proportional to the vibration frequency: from 2% for the first mode (9.4 Hz) to 10% for the third mode (71.4 Hz). However, the measurement errors introduced by the smartphone camera have a significantly lower influence on the values of the identified stiffness parameters than the numbers of modes and parameters taken into account. This is due to the bias–variance trade-off. The results show that consumer-grade electronics can be used as a low-cost and easy-to-use measurement tool if lower-order modes are required.

Słowa kluczowe:
computer vision,smartphone camera,system identification,model updating,uncertain bolted connections

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Mikułowski G. - IPPT PAN
Jankowski Ł. - IPPT PAN
100p.
2.  Ostrowski M., Jedlińska A., Popławski B., Błachowski B., Mikułowski G., Pisarski D., Jankowski , Sliding Mode Control for Semi-Active Damping of Vibrations Using On/Off Viscous Structural Nodes, Buildings, ISSN: 2075-5309, DOI: 10.3390/buildings13020348, Vol.13, No.2, pp.1-16, 2023

Streszczenie:
Structural vibrations have adverse effects and can lead to catastrophic failures. Among various methods for mitigation of vibrations, the semi-active control approaches have the advantage of not requiring a large external power supply. In this paper, we propose and test a sliding mode control method for the semi-active mitigation of vibrations in frame structures. The control forces are generated in a purely dissipative manner by means of on/off type actuators that take the form of controllable structural nodes. These nodes are essentially lockable hinges, modeled as viscous dampers, which are capable of the on/off control of the transmission of bending moments between the adjacent beams. The control aim is formulated in terms of the displacement of a selected degree of freedom. A numerically effective model of such a node is developed, and the proposed control method is verified in a numerical experiment of a four-story shear structure subjected to repeated random seismic excitations. In terms of the root-mean-square displacement, the control reduced the response by 48.4-78.4% on average, depending on the number and placement of the applied actuators. The peak mean amplitude at the first mode of natural vibrations was reduced by as much as 70.6-96.5%. Such efficiency levels confirm that the proposed control method can effectively mitigate vibrations in frame structures.

Słowa kluczowe:
semi-active control,sliding mode control,structural control,controllable nodes,on/off nodes,damping of vibrations

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Jedlińska A. - IPPT PAN
Popławski B. - IPPT PAN
Błachowski B. - IPPT PAN
Mikułowski G. - IPPT PAN
Pisarski D. - IPPT PAN
Jankowski  - IPPT PAN
70p.
3.  Ostrowski M., Błachowski B., Wójcik B., Żarski M., Tauzowski P., Jankowski , A framework for computer vision-based health monitoring of a truss structure subjected to unknown excitations, Earthquake Engineering and Engineering Vibration, ISSN: 1993-503X, DOI: 10.1007/s11803-023-2154-3, pp.1-17, 2023

Streszczenie:
Computer vision (CV) methods for measurement of structural vibration are less expensive, and their application is more straightforward than methods based on sensors that measure physical quantities at particular points of a structure. However, CV methods produce significantly more measurement errors. Thus, computer vision-based structural health monitoring (CVSHM) requires appropriate methods of damage assessment that are robust with respect to highly contaminated measurement data. In this paper a complete CVSHM framework is proposed, and three damage assessment methods are tested. The first is the augmented inverse estimate (AIE), proposed by Peng et al. in 2021. This method is designed to work with highly contaminated measurement data, but it fails with a large noise provided by CV measurement. The second method, as proposed in this paper, is based on the AIE, but it introduces a weighting matrix that enhances the conditioning of the problem. The third method, also proposed in this paper, introduces additional constraints in the optimization process; these constraints ensure that the stiff ness of structural elements can only decrease. Both proposed methods perform better than the original AIE. The latter of the two proposed methods gives the best results, and it is robust with respect to the selected coefficients, as required by the algorithm.

Słowa kluczowe:
computer vision,structural health monitoring,physics-based graphical models,augmented inverse estimate,model updating,non-negative least square method

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Wójcik B. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Żarski M. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Tauzowski P. - IPPT PAN
Jankowski  - IPPT PAN
70p.
4.  Żarski M., Wójcik B., Miszczak J.A., Błachowski B., Ostrowski M., Computer Vision based inspection on post-earthquake with UAV synthetic dataset, IEEE Access, ISSN: 2169-3536, DOI: 10.1109/ACCESS.2022.3212918, pp.1-11, 2022

Streszczenie:
The area affected by the earthquake is vast and often difficult to entirely cover, and the earthquake itself is a sudden event that causes multiple defects simultaneously, that cannot be effectively traced using traditional, manual methods. This article presents an innovative approach to the problem of detecting damage after sudden events by using interconnected set of deep machine learning models organized in a single pipeline and allowing for easy modification and swapping models seamlessly. Models in the pipeline were trained with a synthetic dataset and were adapted to be further evaluated and used with unmanned aerial vehicles (UAVs) in real-world conditions. Thanks to the methods presented in the article, it is possible to obtain high accuracy in detecting buildings defects, segmenting constructions into their components and estimating their technical condition on the basis of a single drone flight.

Słowa kluczowe:
Seismic measurements, Safety, Training data, Earthquakes, Computer vision, Machine learning, Autonomous aerial vehicles, Drones, Synthetic data

Afiliacje autorów:
Żarski M. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Wójcik B. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Miszczak J.A. - inna afiliacja
Błachowski B. - IPPT PAN
Ostrowski M. - IPPT PAN
100p.
5.  Garus S., Błachowski B., Sochacki W., Jaskot A., Kwiatoń P., Ostrowski M., Šofer M., Kapitaniak T., Mechanical vibrations: recent trends and engineering applications, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2022.140351, Vol.70, No.1, pp.1-12, 2022

Streszczenie:
Although the study of oscillatory motion has a long history, going back four centuries, it is still an active subject of scientific research. In this review paper prospective research directions in the field of mechanical vibrations were pointed out. Four groups of important issues in which advanced research is conducted were discussed. The first are energy harvester devices, thanks to which we can obtain or save significant amounts of energy, and thus reduce the amount of greenhouse gases. The next discussed issue helps in the design of structures using vibrations and describes the algorithms that allow to identify and search for optimal parameters for the devices being developed. The next section describes vibration in multi-body systems and modal analysis, which are key to understanding the phenomena in vibrating machines. The last part describes the properties of granulated materials from which modern, intelligent vacuum-packed particles are made. They are used, for example, as intelligent vibration damping devices.

Słowa kluczowe:
mechanical vibrations, energy harvesting, modal analysis, granular material

Afiliacje autorów:
Garus S. - Czestochowa University of Technology (PL)
Błachowski B. - IPPT PAN
Sochacki W. - Czestochowa University of Technology (PL)
Jaskot A. - Czestochowa University of Technology (PL)
Kwiatoń P. - Czestochowa University of Technology (PL)
Ostrowski M. - IPPT PAN
Šofer M. - Technical University of Ostrava (CZ)
Kapitaniak T. - Lodz University of Technology (PL)
100p.
6.  Ostrowski M., Błachowski B., Popławski B., Pisarski D., Mikułowski G., Jankowski Ł., Semi‐active modal control of structures with lockable joints: general methodology and applications, STRUCTURAL CONTROL AND HEALTH MONITORING, ISSN: 1545-2255, DOI: 10.1002/stc.2710, Vol.28, No.5, pp.e2710-1-24, 2021

Streszczenie:
In this study, a novel modal control strategy by means of semi-actively lockable joints is proposed. The control strategy allows for a directed flow of energy between vibrational modes, which makes it suitable not only for vibration attenuation purposes but also for energy scavenging driven by electromechanical energy harvesters. The proposed control strategy is an extension of the prestress-accumulation release (PAR) technique; however, it introduces also new concepts that increase the efficiency of the overall control system. Contrary to the PAR, the proposed method requires measurement of both strains in the vicinity of the semi-active joints and translational velocities that provide global information about system behavior. The latter aspect requires the control system to be organized within a hierarchical feedback architecture. The benefit from this higher complexity of the control system is its better performance compared to the PAR. The proposed semi-active modal control not only attenuates structural vibration faster, but it also achieves this goal with a smaller number of switches implemented in the joints. The effectiveness of the proposed methodology has been demonstrated on structures equipped with two lockable joints. Two practical examples have been investigated: one employs the concept of vibration-based energy harvesting for a two-story frame structure, while the second one reduces vibration of an eight-story frame structure subjected to kinematic excitation.

Słowa kluczowe:
energy harvesting, lockable joint, modal coupling, semi-active control, vibration attenuation

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Popławski B. - IPPT PAN
Pisarski D. - IPPT PAN
Mikułowski G. - IPPT PAN
Jankowski Ł. - IPPT PAN
140p.
7.  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, Vol.35, No.10, pp.1085-1100, 2020

Streszczenie:
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.

Słowa kluczowe:
optimal sensor placement, effective independence method, Fisher information matrix

Afiliacje autorów:
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
140p.
8.  Ostrowski M., Błachowski B., Bocheński M., Piernikarski D., Filipek P., Janicki W., Design of nonlinear electromagnetic energy harvester equipped with mechanical amplifier and spring bumpers, BULLETIN OF THE POLISH ACADEMY OF SCIENCES: TECHNICAL SCIENCES, ISSN: 0239-7528, DOI: 10.24425/bpasts.2020.135384, Vol.68, No.6, pp.1-11, 2020

Streszczenie:
The main drawback of vibration-based energy harvesting is its poor efficiency due to small amplitudes of vibration and low sensitivity at frequencies far from resonant frequency. The performance of electromagnetic energy harvester can be improved by using mechanical enhancements such as mechanical amplifiers or spring bumpers. The mechanical amplifiers increase range of movement and velocity, improving also significantly harvester efficiency for the same level of excitation. As a result of this amplitude of motion is much larger comparing to the size of the electromagnetic coil. This in turn imposes the need for modelling of electromagnetic circuit parameters as the function of the moving magnet displacement. Moreover, high velocities achieved by the moving magnet reveal nonlinear dynamics in the electromagnetic circuit of the energy harvester. Another source of nonlinearity is the collision effect between magnet and spring bumpers. It has been shown that this effect should be carefully considered during design process of the energy harvesting device. The present paper investigates the influence of the above-mentioned nonlinearities on power level generated by the energy harvester. A rigorous model of the electromagnetic circuit, derived with aid of the Hamilton's principle of the least action, has been proposed. It includes inductance of the electromagnetic coil as the function of the moving magnet position. Additionally, nonlinear behaviour of the overall electromagnetic device has been tested numerically for the case of energy harvester attached to the quarter car model moving on random road profiles. Such a source of excitation provides wide band of excitation frequencies, which occur in variety of real-life applications.

Słowa kluczowe:
energy harvesting, velocity amplification, nonlinear electromagnetic circuit, spring bumper, quarter car model

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Bocheński M. - Lublin University of Technology (PL)
Piernikarski D. - inna afiliacja
Filipek P. - Lublin University of Technology (PL)
Janicki W. - inna afiliacja
100p.
9.  Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Modal energy transfer by controlled structural connections, DIAGNOSTYKA, ISSN: 1641-6414, DOI: 10.29354/diag/116692, Vol.21, No.1, pp.61-70, 2020

Streszczenie:
This paper describes a semi-active control strategy that allows to transfer the vibration energy from an arbitrarily induced to a selected structural mode. The intended aim of the proposed control strategy is energy harvesting from structural vibrations. Another potential application is related to structural safety. In the paper, a mathematical model is first introduced to describe the phenomenon of vibrational energy transfer, and then, based on this model, an efficient semi-active control strategy is proposed. Finally, some problems related to measurement techniques are discussed. The effectiveness of the proposed methodology is demonstrated in an example of energy transfer between vibrational modes of a three-bar planar frame structure.

Słowa kluczowe:
vibration energy, modal control, lockable joint, modal coupling

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Jankowski Ł. - IPPT PAN
Pisarski D. - IPPT PAN
20p.
10.  Bocheński M., Augustyniak M., Ostrowski M., Jarzyna W., The influence of control algorithms on the effectiveness of vibration reduction of an active composite beam, PRZEGLĄD ELEKTROTECHNICZNY, ISSN: 0033-2097, DOI: 10.15199/48.2016.08.45, No.8, pp.166-169, 2016

Streszczenie:
The paper presents application of the MFC actuator and selected control algorithms to the suppression of the composite cantilever beam vibrations. The first part concentrates on the identification of the real structure’s parameters. The numerical model is based on the Euler-Bernoulli beam theory with a nonlinear curvature component. The second part draws on numerical simulations and leads to the identification of optimal control parameters. Finally, the determined parameters are examined in an experimental laboratory system equipped with a DSP controller.

Słowa kluczowe:
MFC actuator, control algorithm, active beam, DSP controller

Afiliacje autorów:
Bocheński M. - Lublin University of Technology (PL)
Augustyniak M. - Induster Sp. z o.o. (PL)
Ostrowski M. - IPPT PAN
Jarzyna W. - Lublin University of Technology (PL)
14p.
11.  Filipek P.Z., Ostrowski M., Optimal energy source for an environmentally-friendly go-kart, Journal of Ecological Engineering, ISSN: 2299-8993, DOI: 10.12911/22998993/65454, Vol.17, No.5, pp.90-95, 2016

Streszczenie:
A method for a sizing of an electromechanical battery for electrical go-kart was presented in the paper. The main goal of this research was to replace the internal combustion (IC) engine by an electric drive system taking into account the traction properties, on the one hand and the duration of operation on a single charge and the number of the battery life cycles on the other. The proposed method permits an entire depreciation of the price of the vehicle before the degradation of the battery occurs. The results of the study have been used to adjust the source for electric go-karts that will be mass produced.

Słowa kluczowe:
electrical vehicle, go-kart, optimal battery sizing, traction simulation

Afiliacje autorów:
Filipek P.Z. - Lublin University of Technology (PL)
Ostrowski M. - inna afiliacja
12p.
12.  Ostrowski M., Jarzyna W., Redukcja drgań obiektu nieliniowego z regulatorem adaptacyjnym proporcjonalno-różniczkującym o strukturze MRAS, IAPGOŚ, ISSN: 2083-0157, DOI: 10.5604/20830157.1194278, Vol.6, No.1, pp.51-54, 2016

Streszczenie:
W artykule zaprezentowano metodę adaptacji algorytmu sterowania aktuatorem MFC służącym do redukcji drgań nieliniowych belki wysięgnikowej. Zastosowany opis matematyczny regulatora PD zaprojektowano jako strukturę MRAS, a algorytm adaptacji oparty jest o zasadę Lapunowa. Przeprowadzone badania symulacyjne określiły odporność algorytmu na błędy modelowania oraz na występujące w rzeczywistych systemach opóźnienia sprzętowe.

Słowa kluczowe:
regulacja adaptacyjna, algorytm adaptacji Lapunowa, drgania belki wysięgnikowej, aktuator MFC

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Jarzyna W. - Lublin University of Technology (PL)
7p.

Lista rozdziałów w ostatnich monografiach
1. 
Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Projektowanie i dynamika urządzeń mechatronicznych, rozdział: Structural vibration control using semi-actively switched lockable joints, Katedra Robotyki i Mechatroniki AGH, pp.221-228, 2019

Prace konferencyjne
1.  Błachowski B., Ostrowski M., Mikułowski G., Jankowski Ł., Mode matching vs Bayesian approach for model updating of frame structure with uncertain bolted connection, ISMA2022 / USD2022, International Conference on Noise and Vibration Engineering / International Conference on Uncertainty in Structural Dynamics, 2022-09-12/09-14, Leuven (BE), pp.1325-1334, 2022

Streszczenie:
In this study we show pros and cons of two frequently used approaches for model updating and parametric identification of structural system assembled by uncertain bolted connections. The comparison between classical mode matching and a recently proposed Bayesian approach is demonstrated. Classical methods for modal updating based on modal sensitivity require matching of modal parameters extracted from measurement data with those obtained numerically. Alternative approach is based on a probabilistic framework with the aid of Bayesian methodology. Such an approach explicitly includes the problem of a trade-off between modeling and measurement errors. These two methods are compared an a laboratory-scale three-story frame with unknown parameters corresponding to bolted connections. A total of 82 degrees of freedom are measured using 4 bidirectional accelerometers and roving sensor technique.

Afiliacje autorów:
Błachowski B. - IPPT PAN
Ostrowski M. - IPPT PAN
Mikułowski G. - IPPT PAN
Jankowski Ł. - IPPT PAN
20p.
2.  Błachowski B., Ostrowski M., Żarski M., Wójcik B., Tauzowski P., Jankowski Ł., An Efficient Computer Vision-Based Method for Estimation of Dynamic Displacements in Spatial Truss Structures, EWSHM 2022, 10th European Workshop on Structural Health Monitoring, 2022-07-04/07-07, Palermo (IT), DOI: 10.1007/978-3-031-07258-1_49, Vol.254, pp.474-484, 2022

Streszczenie:
In the present study a comparison of frequently used computer vision (CV)-based methods for structural health monitoring of truss structures is shown. The attention is paid to template matching methods that can be classified into one of two groups: area-based and feature-based methods. Synthetic but realistic video is used in this study. Results of the comparison are reliable due to the fact that the exact displacements are known from the finite element model of the investigated structure. From the variety of tested CV methods, the Kanade–Lucas–Tomasi algorithm with FREAK-based repetitive correction outperforms the remaining tested methods in terms of the computation time with a negligibly greater estimation error.

Słowa kluczowe:
computer vision, structural health monitoring, physics-based graphics models (PBGM), IC-SHM 2021, benchmark test

Afiliacje autorów:
Błachowski B. - IPPT PAN
Ostrowski M. - IPPT PAN
Żarski M. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Wójcik B. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Tauzowski P. - IPPT PAN
Jankowski Ł. - IPPT PAN
20p.
3.  Błachowski B., Świercz A., Ostrowski M., Tauzowski P., Jankowski Ł., Multi-type sensor placement for structural health monitoring of tied-arch bridges, EWSHM 2020, 10th European Workshop on Structural Health Monitoring, 2020-07-04/07-07, Palermo (IT), DOI: 10.1007/978-3-030-64594-6_29, Vol.127, pp.286-297, 2021

Streszczenie:
Performance of any Structural Health Monitoring (SHM) system strongly depends on a set of sensors which are distributed over the structure under investigation. Optimal deployment of sensors on large scale structures such as tied-arch bridges is quite a challenging problem. Moreover, deployment of a sensor network consisting of different types of sensors (accelerometers, inclinometers or strain gauges) over a large scale bridge renders the task of optimization even more demanding. In the present study, a conventional sensor placement method for distribution of a homogenous sensor network is expanded to the heterogeneous case. First, the basic equations governing the estimation error will be recalled. Then, the Fisher information matrix is assembled using normalized translational and rotational mode shapes. Finally, a computational procedure is proposed which allows optimal sensor positions to be selected among thousands candidate locations. The effectiveness of the proposed strategy is demonstrated using a realistic example of a tied-arch bridge located in Poland.

Słowa kluczowe:
optimal sensor placement, structural health monitoring, tied-arch bridges, multi-type sensor network

Afiliacje autorów:
Błachowski B. - IPPT PAN
Świercz A. - IPPT PAN
Ostrowski M. - IPPT PAN
Tauzowski P. - IPPT PAN
Jankowski Ł. - IPPT PAN
4.  Błachowski B., Ostrowski M., 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), DOI: 10.1063/5.0007817, Vol.2239, No.1, pp.020002-1-11, 2020

Streszczenie:
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.

Afiliacje autorów:
Błachowski B. - IPPT PAN
Ostrowski M. - IPPT PAN
Tauzowski P. - IPPT PAN
Świercz A. - IPPT PAN
Jankowski Ł. - IPPT PAN
20p.
5.  Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Inverse Lyapunov based method for semi-active control of energy transfer between vibration modes, SMART 2019, 9th ECCOMAS Thematic Conference on Smart Structures and Materials, 2019-07-08/07-11, Paris (FR), pp.345-356, 2019

Streszczenie:
This contribution proposes a semi-active control approach for a directed energy transfer between structural vibrational modes. The motivation is the intended localization of the vibration energy in a selected mode for the purpose of energy harvesting and mitigation of structural vibrations. The proposed control strategy aims at the instantaneous maximization of the energy transfer to the target mode. It is based on an untypical approach of dynamic structural reconfiguration and implemented using a semi-actively controllable node: a lockable joint. Such a joint, depending on the control signal, can act as a hinge or as a typical frame node. Effectively, it provides thus an on/off ability to control the transfer of bending moments between the adjacent structural elements. The effectiveness of the approach is demonstrated in a numerical example of a plane frame structure.

Słowa kluczowe:
Modal control, Semi-active control, Lockable joints, Energy harvesting

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Jankowski Ł. - IPPT PAN
Pisarski D. - IPPT PAN

Abstrakty konferencyjne
1.  Tauzowski P., Jarosik P., Żarski M., Wójcik B., Ostrowski M., Blachowski B., Jankowski Ł., Computer vision-based inspections of civil infrastructure, Modelling in Mechanics 2022, 2022-05-26/05-27, Rožnov pod Radhoštěm (CZ), pp.1-7, 2022

Streszczenie:
The uNET neural network architecture has
shown very promising results when applied to semantic
segmentation of biomedical images. The aim of this work
is to check whether this architecture is equally applicable
to semantic segmentation distinguishing the structural
elements of railway viaducts. Artificial images generated
by a computer graphics program rendering the 3D model
of the viaduct in a photorealistic manner will be used as
data sets. This approach produces a large number of
images that provide a solid training set for machine
learning model.

Słowa kluczowe:
Computer vision, deep learning semantic segmentation

Afiliacje autorów:
Tauzowski P. - IPPT PAN
Jarosik P. - IPPT PAN
Żarski M. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Wójcik B. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Ostrowski M. - IPPT PAN
Blachowski B. - inna afiliacja
Jankowski Ł. - IPPT PAN
2.  Ostrowski M., Błachowski B., Mikułowski G., Jankowski Ł., Comparison of mode matching and bayesian approach for parametric identification of frames with bolted connections, EACS 2022, 7th European Conference on Structural Control, 2022-07-10/07-13, Warszawa (PL), pp.86-86, 2022

Streszczenie:
Nowadays engineering studies require the use of the sophisticated finite element (FE) models consisting of hundreds if not thousands of degrees of freedom. However, using only such models does not allow for accurate reproduction of physical properties of real structures. To overcome this problem usually model updating (MU) techniques are employed. MU usually has one of two goals: 1) modification of some parameters of the model in order to minimize error between output of the FE model and experimental data obtained from the real system, and 2) identification of some properties of the real system using both experimental data and updated FE model. The former case relates to finding the model for performing simulations of the behaviour of the real system. In the later case MU can be applied in damage assessment process. Due to modelling uncertainties minimization of the error between measured and model output does not always provides the most accurate parametric identification. In this research unknown parameters describing rotational stiffness of bolted connections in a frame structure are estimated. Effectiveness of the two competitive model updating methods are compared. The first is based on modal sensitivities and minimizes error between numerical and experimental modal data. It requires matching of the numerical modes with the experimental ones, hence it is often called mode matching. The second is based on probabilistic Bayesian framework. In this approach maximum a posteriori (MAP) estimate of the unknown parameters is searched. It provides an augmented optimization allowing for model updating without mode matching. Moreover, this method is intended for parametric identification and explicitly includes the modelling errors into the problem formulation. In this study vibration modes are obtained from laboratory-scale frame with uncertain bolted connections. It is shown that assembly imperfections have significant influence on the mode shapes of the frame. The results also show that the two methods for model updating provide significantly different values of the identified stiffness parameters for the investigated bolted connections.

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Mikułowski G. - IPPT PAN
Jankowski Ł. - IPPT PAN
3.  Ostrowski M., Błachowski B., Żarski M., Wójcik B., Tauzowski P., Jankowski Ł., Comparison of the accuracy of computer vision-based methods for estimation of structural displacements using synthetic video data, EACS 2022, 7th European Conference on Structural Control, 2022-07-10/07-13, Warszawa (PL), pp.66-67, 2022

Streszczenie:
Despite significant advances in structural health monitoring (SHM), the design of contact sensor networks and their power supply for large-scale structures is still expensive and difficult. Due to the recent progress in computer vision (CV) it is possible to monitor structural components or even whole structures with the aid of digital cameras that allow to avoid the use of the contact sensors. However, CV-based measurements have a significantly lower accuracy than the techniques based on the contact sensors. Moreover, the amount of benchmark data available for development, testing and comparison of CV-based methods is limited. This problem has been partially overcome in recent years by the use of the physics-based graphical models (PBGM) in generation of synthetic but realistic video data. In this work, a comparison of two popular methods of CV-based object tracking applicable in SHM is discussed. PBGM-based videos used in this study are a part of The 2nd International Competition for Structural Health Monitoring'. Exact structural displacements are available due to the fact that PBGM-based video are generated using the structural model. Hence, calculation of the error metrics is straightforward and reliable. The PBGM-based videos show a spatial truss subjected to an unknown excitation.

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Żarski M. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Wójcik B. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Tauzowski P. - IPPT PAN
Jankowski Ł. - IPPT PAN
4.  Jankowski Ł., Popławski B., Ostrowski M., Jedlińska A., Mikułowski G., Błachowski B., Pisarski D., Wiszowaty R., Mróz A., Orłowska A., Hou J., Holnicki-Szulc J., Semi-active mitigation of free and forced vibrations by means of truss-frame nodes, CMM-SolMech 2022, 24th International Conference on Computer Methods in Mechanics; 42nd Solid Mechanics Conference, 2022-09-05/09-08, Świnoujście (PL), pp.1-2, 2022

Streszczenie:
This contribution reviews a recently proposed control strategy for mitigation of vibrations based on the Prestress-Accumulation Release (PAR) approach [1]. The control is executed by means of semi-actively controllable truss-frame nodes. Such nodes have an on/off ability to transfer bending moments: they are able to temporary switch their operational characteristics between the truss-like and the frame-like behaviors. The focus is not on local energy dissipation in the nodes treated as friction dampers, but rather on stimulating the global transfer of vibration energy to high-order modes. Such modes are high-frequency and thus highly dissipative by means of the standard mechanisms of material damping. The transfer is triggered by temporary switches to the truss-like state performed at the moments of a high local bending strain. A sudden removal of a kinematic constraint releases the locally accumulated strain energy into high-frequency and quickly damped vibrations.
The first formulation investigated global control laws [1]. Recent approaches generalized it to decen-tralized control with a local-only feedback, which was tested in damping of free vibrations [2] as well as forced vibrations [3]. Recently, a global formulation was proposed that aims at a targeted energy transfer between specific vibration modes [4], and attempts were made to go beyond skeletal struc-tures [5]. Numerical and experimental results will be presented to confirm the high effectiveness of the approach in mitigation of free, forced random and forced harmonic vibrations.

Afiliacje autorów:
Jankowski Ł. - IPPT PAN
Popławski B. - IPPT PAN
Ostrowski M. - IPPT PAN
Jedlińska A. - IPPT PAN
Mikułowski G. - IPPT PAN
Błachowski B. - IPPT PAN
Pisarski D. - IPPT PAN
Wiszowaty R. - IPPT PAN
Mróz A. - IPPT PAN
Orłowska A. - IPPT PAN
Hou J. - Dalian University of Technology (CN)
Holnicki-Szulc J. - IPPT PAN
5.  Ostrowski M., Błachowski B., Mikułowski G., Jankowski Ł., Identification of dynamic characteristics of uncertain bolted connections in a frame structure, CMM-SolMech 2022, 24th International Conference on Computer Methods in Mechanics; 42nd Solid Mechanics Conference, 2022-09-05/09-08, Świnoujście (PL), pp.1-2, 2022

Streszczenie:
Parametric identification of structures and their components can be encountered in many engineering problems such as damage assessment or model updating for the control purposes. In the present study the attention is on two approaches to model updating. The first approach is the classical penalty func-tion that minimizes the square norm of the error between experimental and numerical modal data. The second one is a probabilistic Bayesian framework that maximizes the a posteriori probability density function of the unknown parameters based on the experimental data. The main difference between these two approaches is related to the fact that the penalty function methods requires matching of the numerical data with those obtained experimentally. The Bayesian approach is not vulnerable to this problem, but it requires more weighting parameters to be selected. An improper selection of these parameters leads to a worse identification accuracy. In this work, the two approaches are compared using data obtained from experiments on a laboratory-scale frame with highly uncertain bolted connec-tions. 17 uncertain stiffness parameters are to be identified: 16 of them correspond to the bolted con-nections and one to the Young modulus of the beams. 82 degrees of freedom are measured with the aid of 4 bidirectional accelerometers and roving sensor technique. Experimental modal data used for model updating contain nine mode shapes and the corresponding natural frequencies within the fre-quency range from 0 to 1 kHz. The research is divided into three steps: (1) model class selection, (2) assessment of the parameter identifiability and (3) updating of the selected model with the aid of both examined model updating methods.

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Mikułowski G. - IPPT PAN
Jankowski Ł. - IPPT PAN
6.  Ostrowski M., Błachowski B., Żarski M., Wójcik B., Tauzowski P., Jankowski Ł., Computer vision-based vibration measurement, Modelling in Mechanics 2022, 2022-05-26/05-27, Rožnov pod Radhoštěm (CZ), pp.1-6, 2022

Streszczenie:
In the present study a benchmark test of selected methods of template matching-bated methods for computer vision-based object tracking is performed. The attention is paid to compare these methods in terms of estimation of nodal displacements in a flexible truss structure, aiming at assessment of their reliability in Structural Health Monitoring (SHM) applications. Thanks to the use of synthetic but realistic videos generated with the aid of physics-based graphics models (PBGM), exact displacement of tracked structural nodes are known. Therefore, reliable assessment of the accuracy of the examined methods is possible.

Słowa kluczowe:
computer vision, structural health monitoring, physics-based graphics models (PBGM)

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Żarski M. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Wójcik B. - Institute of Theoretical and Applied Informatics, Polish Academy of Sciences (PL)
Tauzowski P. - IPPT PAN
Jankowski Ł. - IPPT PAN
7.  Ostrowski M., Błachowski B., Świercz A., Tauzowski P., Olaszek P., Jankowski Ł., Efficient Method for Optimal Sensor Placement in Large-scale Structures, CIMTEC 2022, 15th International Conference on Modern Materials and Technologies - 9th Forum on New Materials, 2022-06-25/06-29, Perugia (IT), pp.1, 2022

Streszczenie:
In practice, the broadly used finite element (FE) models can have very large number of degrees of freedom (DOFs). A small subset of DOFs representing sensor locations that provides an extremum of a selected objective function corresponding to a metric of the expected measurement accuracy is sought. Thus, optimal sensor placement is characterized by its complex combinatorial nature and tremendous computational effort required. With the aid of convex relaxation, the proposed approach allows one to transform the original combinatorial problem into its continuous counterpart, which requires smaller computational effort – by a few orders of magnitude than famous Effective Independence method. The effectiveness of the method has been demonstrated using an example of a FE model of an existing railway bridge. First, the FE model has been calibrated with measured responses of the bridge under the moving load of a passing train. Then, sensor layout has been obtained in such a way that it optimises the estimate of modal coordinates of the mode shapes participating most significantly in the measured structural response. The authors acknowledge the support of the National Science Centre, Poland (grant agreement 2018/31/B/ST8/03152).

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Świercz A. - IPPT PAN
Tauzowski P. - IPPT PAN
Olaszek P. - Instytut Badawczy Dróg i Mostów (PL)
Jankowski Ł. - IPPT PAN
8.  Jankowski Ł., Popławski B., Ostrowski M., Jedlińska A., Mikułowski G., Błachowski B., Pisarski D., Wiszowaty R., Mróz A., Holnicki-Szulc J., Semi-active damping of structural vibrations using controllable truss-frame nodes, 8WCSCM, 8th World Conference on Structural Control and Monitoring, 2022-06-05/06-08, Orlando, Florida (US), pp.1, 2022

Streszczenie:
This contribution reviews a recently proposed semi-active control approach based on the Prestress-Accumulation Release strategy, which aims at damping of structural vibrations by promoting vibration energy transfer from lower- into higher-order modes that have significant material damping. Unlike typical semi-active control, which focuses on local dissipation in actuators, the aim is to trigger natural global damping mechanisms. The actuators are controllable truss-frame nodes: lockable hinges that can change their mode of operation from a frame node (locked hinge) into truss node (free rotation). Sudden removal of such a kinematic constraint releases the accumulated bending energy into high-frequency quickly damped local vibrations. Two formulations are reviewed: decentralized with local-only feedback, and global, which aims at a targeted energy transfer between specific modes. Experimental results confirm the effectiveness using free, forced harmonic and random vibrations.

Afiliacje autorów:
Jankowski Ł. - IPPT PAN
Popławski B. - IPPT PAN
Ostrowski M. - IPPT PAN
Jedlińska A. - IPPT PAN
Mikułowski G. - IPPT PAN
Błachowski B. - IPPT PAN
Pisarski D. - IPPT PAN
Wiszowaty R. - IPPT PAN
Mróz A. - IPPT PAN
Holnicki-Szulc J. - IPPT PAN
9.  Ostrowski M., Błachowski B., Mikułowski G., Jankowski Ł., Parametric identification of uncertain bolted connections with Bayesian approach, LSCE, XXVII Conference of Lightweight Structures in Civil Engineering, 2021-12-02/12-03, Łódź (PL), pp.93-96, 2021

Streszczenie:
The paper presents the parametric identification of structural connections characterised by highly uncertain stiffness. Such uncertainties often appear in structural bolted connections. One of the common problems in parametric identification with the use of modal data is the problem of the mode matching. In this work the model updating method based on the Bayesian approach was used to identify the unknown parameters. Due to the probabilistic framework it allows to avoid the problem of the mode matching. A laboratory-scale frame structure is considered in this research, however this structure contains bolted connections common also in large-scale light-weight structures. The problem of parametric identification has been decomposed into the following tasks: (a) selection of the finite element model, (b) evaluation of the identifiability of the parameters, and (c) updating the finite element model with the use of available measurement data.

Słowa kluczowe:
Bayesian approach, mode matching, system identification, model updating, bolted connections

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Mikułowski G. - IPPT PAN
Jankowski Ł. - IPPT PAN
10.  Ostrowski M., Błachowski B., Mikułowski G., Jankowski Ł., Bayesian approach for efficient identification of highly uncertain structural parameters, WEO 2021, 2nd Workshop on Engineering Optimization, 2021-10-07/10-08, Warszawa (PL), pp.39-43, 2021
11.  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

Streszczenie:
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.

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Świercz A. - IPPT PAN
Błachowski B. - IPPT PAN
Tauzowski P. - IPPT PAN
Jankowski Ł. - IPPT PAN
12.  Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Półaktywne sterowanie drganiami konstrukcji przy użyciu dynamicznie aktywowanych połączeń, SAM2019, XVIII Szkoła Analizy Modalnej, 2019-06-06/06-07, Kraków (PL), pp.1, 2019

Streszczenie:
W ostatnim czasie wiele prac naukowych poświęcono problemom półaktywnego sterowania drganiami układów mechanicznych. Większość tych prac jednak dotyczy zagadnienia tłumienia drgań, natomiast znacznie mniej z nich obejmuje strategie sterowania na potrzeby odzyskiwania energii z drgających układów. Celem niniejszej pracy jest opracowanie strategii półaktywnego sterowania drganiami, mającej za zadanie przenosić energię drgań wzbudzanych losowo do jednej wybranej postaci drgań własnych. Sterowanie takie realizowane jest przy pomocy dynamicznie rozłączanych węzłów konstrukcyjnych. Węzły w zależności od sygnału sterowania mogą być blokowane w celu przenoszenia momentu zginającego pomiędzy łączonym członami konstrukcji lub odblokowywane, aby pracować jak połączenie przegubowe. Prowadzone badania podstawowe mają wiele potencjalnych zastosowań. Wraz ze zmianą postaci drgań, istnieje możliwość zmiany amplitudy w miejscach, w których zainstalowany jest tłumik lub urządzenie odzyskujące energię (ang. energy-harvester). Możliwe jest również szybkie przeniesienie energii mechanicznej do postaci drgań, która nie zakłóca funkcjonalności konstrukcji lub nie powoduje jej uszkodzenia bądź zmęczenia. W porównaniu do sterowania aktywnego stosowanie sterowania półaktywnego pozwala obniżyć koszty układu, dodatkowo nie powodując destabilizacji konstrukcji [1]. Sterowanie takie może z powodzeniem znaleźć zastosowanie w konstrukcjach o wielu stopniach swobody [2]. Strategia półaktywnego sterowania z użyciem blokowalnych węzłów pierwotnie została opracowana w celu przeniesienia energii drgań do wyższych postaci własnych w celu skutecznej ich redukcji przez tłumienie materiałowe [3]. W niniejszej pracy zaprezentowany zostanie model matematyczny transferu energii oraz oparte na nim prawo sterowania. Dodatkowo przedstawiony zostanie przykład numeryczny pokazujący, że transfer energii mechanicznej jest możliwy nawet wtedy, gdy mierzone są tylko pierwsze – podstawowe – postacie drgań własnych. Prowadzone badania zostały wsparte przez Narodowe Centrum Nauki w ramach projektu Re-Conf (DEC-2017/25/B/ST8/01800).

Słowa kluczowe:
sterowanie półaktywne, analiza modalna, blokowane węzły

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Jankowski Ł. - IPPT PAN
Pisarski D. - IPPT PAN
13.  Ostrowski M., Błachowski B., Jankowski Ł., Pisarski D., Semi-Active Control of Mechanical Energy Transfer Between Vibrational Modes, SolMech 2018, 41st SOLID MECHANICS CONFERENCE, 2018-08-27/08-31, Warszawa (PL), No.P136, pp.408-409, 2018

Streszczenie:
The vibration attenuation problem has been solved using many different methods, some of which involve the use of advanced control algorithms. The topic of harvesting the energy of structural vibrations is less explored. For that reason, this contribution studies the problem of conversion of mechanical energy of vibrations. The paper presents a method of semi-active control, which is applied to dynamically transfer the vibration energy into a selected vibration mode. The target mode is selected in such a way that the amount of energy that can be recovered during the vibration process is maximized. In other words, switching between two modes is not intended to dissipate the energy of vibrations, but rather to maximize the energy-harvesting potential of the overall system. The concept will be illustrated using an example of a simple frame structure, in which semi-actively controlled lockable joints modify the modal properties of the structure.

Słowa kluczowe:
semi-active control, lockable joints, energy-harvesting

Afiliacje autorów:
Ostrowski M. - IPPT PAN
Błachowski B. - IPPT PAN
Jankowski Ł. - IPPT PAN
Pisarski D. - IPPT PAN

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