inż. Błażej Popławski

Zakład Technologii Inteligentnych (ZTI)
Pracownia Inżynierii Bezpieczeństwa (PIB)
stanowisko: doktorant
telefon: (+48) 22 826 12 81 wew.: 168
pokój: 411
e-mail: bpop

Ostatnie publikacje
1.Popławski B., Mikułowski G., Mróz A., Jankowski Ł., Decentralized semi-active damping of free structural vibrations by means of structural nodes with an on/off ability to transmit moments, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2017.08.012, Vol.100, pp.926-939, 2018

Streszczenie:

This paper proposes, tests numerically and verifies experimentally a decentralized control algorithm with local feedback for semi-active mitigation of free vibrations in frame structures. The algorithm aims at transferring the vibration energy of low-order, lightly-damped structural modes into high-frequency modes of vibration, where it is quickly damped by natural mechanisms of material damping. Such an approach to mitigation of vibrations, known as the prestress-accumulation release (PAR) strategy, has been earlier applied only in global control schemes to the fundamental vibration mode of a cantilever beam. In contrast, the decentralization and local feedback allows the approach proposed here to be applied to more complex frame structures and vibration patterns, where the global control ceases to be intuitively obvious. The actuators (truss–frame nodes with controllable ability to transmit moments) are essentially unblockable hinges that become unblocked only for very short time periods in order to trigger local modal transfer of energy. The paper proposes a computationally simple model of the controllable nodes, specifies the control performance measure, yields basic characteristics of the optimum control, proposes the control algorithm and then tests it in numerical and experimental examples.

Słowa kluczowe:

Damping of vibrations, Smart structures, Semi-active control, Decentralized control, Truss-frame nodes

Afiliacje autorów:

Popławski B.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Jankowski Ł.-IPPT PAN

Prace konferencyjne
1.Popławski B., Mikułowski G., Mróz A., Jankowski Ł., Decentralized damping of vibrations in 2D frame structures using controllable nodes, SMART 2017, 8th Conference on Smart Structures and Materials, 2017-06-05/06-08, Madrid (ES), pp.94-103, 2017

Streszczenie:

Extensive research efforts have been recently devoted to semi-active structural control with its paradigms of smart self-adaptivity and low consumption of energy, which is used for local adaptation rather than to generate external control forces. Considered application areas include adaptive landing gears, seismic isolation systems, vehicle-track/span systems, power train electro-mechanical systems, damping of flexible space structures, vehicle crashworthiness, arctic engineering, wind turbines, etc. A part of the research concerns semi-active management of strain energy for damping of structural vibrations. Early works considered truss structures with stiffness-switched bars. They later evolved into either standalone one degree of freedom stiffness-switched dampers and isolators or investigations in triggering modal energy transfer to highly-damped high-order modes. The latter researches seem all to study the fundamental vibration mode of a cantilever beam with two detachable layers and differ mainly in the actuator technologies; the main idea is to employ actuators for a quick release of the vibration-related strain energy. This research extends the problem to general 2D frames. Controllable truss-frame nodes are incorporated into the structure. Thanks to their controllable ability to transmit moments, they allow for a quick transition between truss and frame modes. We propose a new, decentralized, closed-loop control strategy based on local energy measures. Vibration damping is more effective than in the previously studied control scheme based on a global energy measure, especially for higher vibration modes. Mitigation of vibrations will be presented in representative numerical examples, including a comparison to the global energy-based control strategy. Finally, results of experimental study, conducted on a structure analogous to the one from numerical simulations, will be demonstrated.

Słowa kluczowe:

Vibration damping, Smart structures, Semi-active control, PAR strategy, Decentralized damping strategy

Afiliacje autorów:

Popławski B.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Jankowski Ł.-IPPT PAN
2.Faraj R., Popławski B., Suwała G., Jankowski Ł., Holnicki-Szulc J., Mitigation of dynamic response in frame structures by means of smart joints, SMART 2017, 8th Conference on Smart Structures and Materials, 2017-06-05/06-08, Madrid (ES), pp.138-144, 2017

Streszczenie:

This paper discusses passive and semi-active techniques of structural control by means of smart joints, and then it proposes a specific smart joints system for frame structures and tests its capability in mitigation of free vibrations. Basically, the proposed solution modifies frame beams by addition of truss-type hinges, and its effectiveness relies on the softening effect that occurs in compression due to geometric nonlinearities and which triggers the highly-damped high-frequency response modes of the structure. First, the finite element (FE) model of the specific frame structure with geometrical nonlinearities is derived, and the proposed passive joints are described and incorporated into the model. Then, their principle of operation and effectiveness is examined numerically for the first two natural modes of vibrations with various initial displacement amplitudes. An objective function is proposed to assess joints placement, based on the efficiency in mitigation of the excited vibrations.

Słowa kluczowe:

Vibration Damping, Structure Response, Smart Structure, Structural Control

Afiliacje autorów:

Faraj R.-IPPT PAN
Popławski B.-IPPT PAN
Suwała G.-IPPT PAN
Jankowski Ł.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
3.Popławski B., Graczykowski C., Jankowski Ł., Controllable Truss-Frame Nodes in Semi-Active Damping of Vibrations, Advances in Science and Technology, ISSN: 1662-0356, DOI: 10.4028/www.scientific.net/AST.101.89, Vol.101, pp.89-94, 2017

Streszczenie:

In recent years, vibration damping strategies based on semi-active management of strain energy have attracted a large interest and were proven highly effective. However, most of published research considers simple one degree of freedom systems or study the same basic example (the first vibration mode of a cantilever beam) with the same control strategy. This contribution focuses on truss-frame nodes with controllable moment-bearing ability. It proposes and tests an approach that allows the control strategy to be extended to more complex structures and vibration patterns.

Słowa kluczowe:

adaptive impact absorption, smart structures, semi-active control, safety engineering

Afiliacje autorów:

Popławski B.-IPPT PAN
Graczykowski C.-IPPT PAN
Jankowski Ł.-IPPT PAN
4.Jankowski Ł., Graczykowski C., Pawłowski P., Mikułowski G., Ostrowski M., Popławski B., Faraj R., Suwała G., Holnicki-Szulc J., Adaptive Self-Protection against Shock and Vibration, Advances in Science and Technology, ISSN: 1662-0356, DOI: 10.4028/www.scientific.net/AST.101.133, Vol.101, pp.133-142, 2017

Streszczenie:

This contribution reviews the challenges in adaptive self-protection of structures. A proper semi-active control strategy can significantly increase structural ability to absorb impact-type loads and damp the resulting vibrations. Discussed systems constitute a new class of smart structures capable of a real-time identification of loads and vibration patterns, followed by a low-cost optimum absorption of the energy by structural adaptation. Given the always surging quest for safety, such systems have a great potential for practical applications (in landing gears, road barriers, space structures, etc.). Compared to passive systems, their better performance can be attributed to the paradigm of self-adaptivity, which is ubiquitous in nature, but still sparsely applied in structural engineering. Being in the early stages of development, their ultimate success depends on a concerted effort in facing a number of challenges. This contribution discusses some of the important problems, including these of a conceptual, technological, methodological and software engineering nature.

Słowa kluczowe:

adaptive impact absorption, smart structures, semi-active control, safety engineering

Afiliacje autorów:

Jankowski Ł.-IPPT PAN
Graczykowski C.-IPPT PAN
Pawłowski P.-IPPT PAN
Mikułowski G.-IPPT PAN
Ostrowski M.-IPPT PAN
Popławski B.-IPPT PAN
Faraj R.-IPPT PAN
Suwała G.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
5.Popławski B., Mikułowski G., Mróz A., Sekuła K., Jankowski Ł., A decentralized strategy of structural reconfiguration in mitigation of vibrations, Procedia Engineering, ISSN: 1877-7058, DOI: 10.1016/j.proeng.2017.09.363, No.199, pp.1683-1688, 2017

Streszczenie:

This contribution proposes a decentralized closed-loop control algorithm for semi-active mitigation of free vibrations in frame structures. The control uses dedicated dissipative devices, which consist of two controllable structural nodes placed pairwise in both ends of selected structural beams. The nodes are capable of a controlled transition between the standard frame mode of operation (full moment-bearing ability) and the truss mode in which they do not bear any moments and constitute in fact structural hinges. Synchronous switching is equivalent to reconfiguration of the global structure by (dis)allowing the involved beams to transmit moments and to accumulate vibration energy in the form of their bending strain. Upon switching to the truss mode, the accumulated energy is released into high-frequency local vibrations, which undergo quick dissipation by standard mechanisms of material damping. The approach is illustrated in a numerical example and verified in a preliminary experimental test.

Słowa kluczowe:

Mitigation of vibrations, Semi-active control, Decentralized control, Structural reconfiguration

Afiliacje autorów:

Popławski B.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Sekuła K.-IPPT PAN
Jankowski Ł.-IPPT PAN

Abstrakty konferencyjne
1.Popławski B., Mikułowski G., Jankowski Ł., On-off damping of free vibrations and optimum actuator placement, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), pp.1-2, 2016