Piotr Pawłowski, Ph.D., Eng.

Department of Intelligent Technologies (ZTI)
Division of Safety Engineering (PIB)
position: main specialist
telephone: (+48) 22 826 12 81 ext.: 197
room: 444
e-mail: ppawl

Doctoral thesis
2011-10-27Systemy adaptacyjnej absorpcji obciążeń udarowych: identyfikacja udaru, sterowanie absorberów, dyssypacja energii 
supervisor -- Prof. Jan Holnicki-Szulc, Ph.D., Dr. Habil., Eng., IPPT PAN
644
 
Recent publications
1.Fras T., Murzyn A., Pawłowski P., Defeat mechanisms provided by slotted add-on bainitic plates against small-calibre 7.62 mm x 51 AP projectiles., INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, ISSN: 0734-743X, DOI: 10.1016/j.ijimpeng.2017.01.015, Vol.103, pp.241-253, 2017
Abstract:

Thin steel plates with an array of holes, i.e. perforated plates, are used as a passive add-on improving protective properties of armours against small-calibre projectiles. A number of holes in such plates increases the probability of asymmetrical contact between the plate and the projectile, due to which small-calibre projectiles may be destabilized or fragmented before they reach the main-armour. The aim of the study is to analyse the defeat mechanisms provided by 4-mm-thick slotted super-bainitic plates (Pavise™ SBS 600P) against hard-core 7.62mm P80 0.30 AP×51 (0.308 Win) projectiles. To show the dependence between the hit-point and projectile failure, moments when projectiles hit the pre-armour plate were recorded by an ultra-high speed camera and their behaviour after the impact was captured by the flash X-ray radiography. The obtained results complemented by the Lagrangian FEM analysis confirm that slotted steel plates have high protection effectiveness against small-calibre projectiles.

Keywords:

Light-weight ballistic protectionPerforated add-on armourSuper-bainitic steelArmour-piercing (AP) projectile

Affiliations:
Fras T.-IPPT PAN
Murzyn A.-French-German Research Institute of Saint-Louis (DE)
Pawłowski P.-IPPT PAN
2.Graczykowski C., Pawłowski P., Exact physical model of magnetorheological damper, Applied Mathematical Modelling, ISSN: 0307-904X, DOI: 10.1016/j.apm.2017.02.035, Vol.47, pp.400-424, 2017
Abstract:

This paper attempts to fill the gap in the literature by introducing and discussing an enhanced physical model of the MR damper. The essence of the presented model is to combine the effect of compressibility of the MR fluid enclosed in each chamber with the effect of blocking the flow between the chambers in the case of a low pressure difference. As it will be shown, the concurrence of both considered phenomena significantly affects mechanical behaviour of the damper, influences its dissipative characteristics, and in particular, it is the reason behind the distinctive ‘z-shaped’ force–velocity hysteresis loops observed in experiments. The paper presents explanation of the observed phenomena, detailed derivation of the thermodynamic equations governing response of the damper, their implementation for various constitutive models of the magnetorheological fluid and, finally, formulation of the corresponding reduced and parametric models. Experimental validation shows that proper identification of physical parameters of the proposed mathematical model yields the correct shapes of force–velocity hysteresis loops.

Keywords:

Magnetorheological fluid dampers, Smart fluids, Hysteresis modelling

Affiliations:
Graczykowski C.-IPPT PAN
Pawłowski P.-IPPT PAN
3.Chikahiro Y., Ario I., Nakazawa M., Ono S., Holnicki-Szulc J., Pawłowski P., Graczykowski C., Watson A., Experimental and numerical study of full-scale scissor type bridge, Automation in Construction, ISSN: 0926-5805, DOI: 10.1016/j.autcon.2016.05.007, Vol.71, pp.171-180, 2016
Abstract:

Mobile Bridge™ is a deployable bridge that uses a scissors mechanism to achieve its useful structural form. The bridge has a compact size in its undeployed state and can be transported easily to where it is needed. Its rapid deployment makes this type of bridge very useful in areas struck by natural disasters by enabling vehicles to cross terrain that has been made impassable. In previous research, experiments and analyses were conducted on a small-scale bridge designed for pedestrians. In order to consider a bridge of increased size, it is necessary to assess whether design and analysis techniques of the small scale bridge are applicable to the full-scale one. In this paper, we consider a full-scale deployable bridge with a lower deck and two scissor units, that allows for a light vehicle to pass across. We have carried out a light vehicle loading test in order to investigate its basic structural characteristics. Furthermore, the paper presents the theoretical design method and numerical models based on the experimental work followed by validation and comparison with the obtained experimental values.

Keywords:

Full-scale Mobile Bridge, Scissor type of emergency bridge, Scissors mechanism, Vehicle loading test

Affiliations:
Chikahiro Y.-Shinshu University (JP)
Ario I.-Hiroshima University (JP)
Nakazawa M.-Tohoku Gakuin University (JP)
Ono S.-Japan Construction Method and Machinery Research Institute (JP)
Holnicki-Szulc J.-IPPT PAN
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Watson A.-Loughborough University (GB)
4.Górecka K., Skłodowski M., Pawłowski P., Osowicki G., Belgijski pacjent. Polskie prace badawczo – konserwatorskie przy wielkoformatowym krzywoliniowym obrazie z XVIII w. z katedry Saint-Aubain w Namur, , Vol.21, No.80, pp.62-71, 2016
Abstract:

Paper discusses a concept and conservation methodology of the XVII. century curvilinear canvas painting "Adoration of the Magi" from the Saint-Aubain Cathedral church in Namur (Belgium). Atypical form of the painting bowed in the horizontal plane, adapted to a, wall and its enormous size (3.70 x 4.50 m) required using some innovative technologies and materials. Restoration work required access to both the face and the back of the picture. But how to overturn the painting? How to strengthen its support? How to tight. it? Such problems can be solved only by the interdisciplinary collaboration of a team of professionals. In this way decisions about the conservation were discussed in the group of experts from various disciplines. The article focuses o! n the problem of curvilinear canvas stretching, which is presented fro m different points of view. In the council participated restorers, scientist and engineers. Finally, we agreed that the basic premise of the conservation process was a detailed analysis of the canvas shape and its preservation on each step of the conservation works. The concept required construction of two curved platforms: concave and convex. The new system of the canvas overturning was also designed. An innovating method of strengthening of the canvas vertical direction during lining process by using Kevlar fibres was applied. The XVII. century stretcher frame was preserved as an example of historical construction. The new stretching system was built out of the original stretcher frame. The conservation works were finished in 2014, the painting was put in the frame and fixed on the wall. The optical analysis of its shape achieved one year after showed that its state is stable.

Affiliations:
Górecka K.-Academy of Fine Arts in Warsaw (PL)
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Osowicki G.-other affiliation
5.Holnicki-Szulc J., Graczykowski C., Mikułowski G., Mróz A., Pawłowski P., Wiszowaty R., Adaptive Impact Absorption - the Concept and Potential Applications, INTERNATIONAL JOURNAL OF PROTECTIVE STRUCTURES, ISSN: 2041-4196, DOI: 10.1260/2041-4196.6.2.357, Vol.6, No.2, pp.357-377, 2015
Abstract:

Adaptive Impact Absorption focuses on adaptation of energy absorbing structures to actual dynamic loading by using system of sensors detecting and identifying impact in advance and embedded semi-active dissipaters with controllable mechanical properties. Application of such devices allows to modify dynamic characteristics of the structure during the period of impact and to precisely control the process of energy dissipation. The paper presents an overview of research conducted at the Department of Intelligent Technologies of the Institute of Fundamental Technological Research dedicated to design and applications of various systems of Adaptive Impact Absorption. Wide range of presented examples covers adaptive hydraulic and pneumatic landing gears, skeletal systems equipped with controllable elements and detachable joints as well as adaptive inflatable structures.

Keywords:

adaptive impact absorption, safety engineering, smart structures, optimal control

Affiliations:
Holnicki-Szulc J.-IPPT PAN
Graczykowski C.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Pawłowski P.-IPPT PAN
Wiszowaty R.-IPPT PAN
6.Frąś T., Colard L., Pawłowski P., Perforation of aluminum plates by fragment simulating projectiles (FSP), THE INTERNATIONAL JOURNAL OF MULTIPHYSICS, ISSN: 1750-9548, DOI: 10.1260/1750-9548.9.3.267, Vol.9, No.3, pp.267-286, 2015
Abstract:

The paper describes the ballistic impact test, in which fragment simulating projectiles (FSPs) of a 20-mm-diameter have been used against 40-mmthick plates made of an aluminum alloy AA7020-T651. To perforate plates, the projectiles must have reached a velocity higher than 890 m/s. Based on the performed ballistic test, the plugging failure mode is numerically modeled using the LS-DYNA software package. Results obtained due to the calculations in the Finite Element Method (FEM) are compared with the results from the Smoothed Particle Hydrodynamics (SPH). A condition of geometrical similarity between the target deformed experimentally and its numerical representation is introduced to evaluate the performed simulations.

Keywords:

Ballistic impact test, Fragment simulating projectile (FSP), Plugging failure mode, Smooth Particle Hydrodynamics (SPH), Optical scanning

Affiliations:
Frąś T.-IPPT PAN
Colard L.-French-German Research Institute of Saint-Louis (DE)
Pawłowski P.-IPPT PAN
7.Górecka K., Skłodowski M., Pawłowski P., Szpor J., New materials and methods used in the conservation of the XVIIIth century curvilinear canvas painting 'Adoration of the Magi' from the Ssaint-Aubain cathedral church in Namur, European Journal of Science and Theology, ISSN: 1841-0464, Vol.11, No.2, pp.45-53, 2015
Abstract:

Paper discusses a concept and conservation methodology of the XVIIIth century curvilinear canvas painting ‘Adoration of the Magi’ from the Saint–Aubain Cathedral church in Namur (Belgium). Atypical form of the painting bowed in the horizontal plane, adapted to the apse wall and its very large size (3.70 x 4.50 m) required using some innovative technologies and materials. The basic premise of the conservation process was a detailed analysis of the canvas shape and its preservation on each step of the conservation works. The concept required construction of two curved platforms: concave and convex. The new system of the canvas overturning was also designed. An innovative method of strengthening of the canvas during lining process in vertical direction by using Kevlar fibres was applied. Required strengthening and modification of the stretching frame is also discussed.

Keywords:

curvilinear, large-size, lining, stretching, Kevlar fibres

Affiliations:
Górecka K.-Academy of Fine Arts in Warsaw (PL)
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Szpor J.-Academy of Fine Arts in Warsaw (PL)
8.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.-IPPT PAN
Mróz A.-IPPT PAN
Sala D-IPPT PAN
Pawłowski P.-IPPT PAN
Sekuła K.-other affiliation
Świercz A.-IPPT PAN
9.Górecka K., Skłodowski M., Pawłowski P., Szpor J., Arendarski H., XVIII Century Wooden Stretchers Structure Designed for Large Canvas and an Example of the Assessment Method, ADVANCED MATERIALS RESEARCH, ISSN: 1662-8985, DOI: 10.4028/www.scientific.net/AMR.778.113, Vol.778, pp.113-118, 2013
Abstract:

Paper discusses large size canvas paintings stretching methods and deformations and damages specific for large canvas resulting from an incorrect stretching. Analysis of the preservation state of a wooden stretcher construction and its functionality was an important step in development of the program of conservation work. The case study of M. H Loders painting "Adoration of the Magi" (XVIII c.) from the cathedral Saint - Aubain in Namur (Belgium) is presented. The painting is exhibited 5,5 m above the floor and has a unique shape, as the wooden stretcher frame is adjusted to the round apse walls. Thus usual direct inspection was difficult due to poor access to the reverse side of the painting. Preliminary conclusions on the construction and preservation state of the stretcher frame were drawn on the basis of a thorough inspection of the painting surface. Actual shape of the painting and precise stretchers dimensions were measured with a laser scanner. More information concerning the stretcher frame construction was obtained from a simple micro-camera system combined with LED lighting introduced from the canvas reverse side.

Keywords:

3D Laser Scanner, Deformation, Large - Size Painting, Wooden Stretcher Frame

Affiliations:
Górecka K.-Academy of Fine Arts in Warsaw (PL)
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Szpor J.-Academy of Fine Arts in Warsaw (PL)
Arendarski H.-Academy of Fine Arts in Cracow (PL)
10.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.-IPPT PAN
Świercz A.-IPPT PAN
Sekuła K.-other affiliation
11.Holnicki-Szulc J., Graczykowski C., Mikułowski G., Mróz A., Pawłowski P.K., Smart technologies for adaptive impact absorption, SOLID STATE PHENOMENA, ISSN: 1012-0394, DOI: 10.4028/www.scientific.net/SSP.154.187, Vol.154, pp.187-194, 2009
Abstract:

The article presents a review of recent research carried out in the Department of Intelligent Technologies of Institute of Fundamental Technological Research, dedicated to application of systems for adaptive impact absorption to adaptive aircraft landing gears, novel concept of protective MFM structures, flow-control based airbags, maritime applications of inflatable structures, and development of adaptive wind turbine blade – hub connections.

Keywords:

Adaptive Impact Absorption, Adaptive Structure, Optimal Control

Affiliations:
Holnicki-Szulc J.-IPPT PAN
Graczykowski C.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Pawłowski P.K.-IPPT PAN
12.Graczykowski C., Mikułowski G., Pawłowski P.K., Koncepcja absorbera pneumatycznego do zastosowania w podwoziach aparatów latających z wykorzystaniem układu rozpoznania energii uderzenia, JOURNAL OF AERONAUTICA INTEGRA, ISSN: 1896-8856, Vol.1, No.5, pp.25-31, 2009
Abstract:

Podwozia lotnicze są traktowane przez konstruktorów samolotów jako elementy konieczne, ale z wielu względów mające negatywny wpływ na projekt. Z punktu widzenia aerodynamiki podwozia w trakcie lotu, stawiają dodatkowy opór aerodynamiczny (mniejszy w przypadku podwozi chowanych), a z punktu widzenia możliwości przewożenia ładunków, pochłaniają część masy startowej samolotu, która mogłaby być wykorzystana na transport towarów lub pasażerów. Biorąc pod uwagę takie uwarunkowania, idealne podwozie lotnicze powinno ważyć jak najmniej i zajmować minimalną ilość miejsca.
Obecnie najpopularniejszym rodzajem podwozia stosowanego w lotnictwie jest typ olejowo-gazowy, który charakteryzuje się najkorzystniejszym stosunkiem sprawności do wagi. Sprawność obecnie stosowanych podwozi lotniczych dochodzi do 80%. Aczkolwiek jest to wartość, która jest uzyskiwana dla jednego predefiniowanego przypadku lądowania z określoną energią uderzenia samolotu o pas startowy. Praktyka pokazuje, że w rzeczywistości zmienność warunków lądowania jest dużo większa niż zakres, na jaki można zaprojektować klasyczne podwozie pasywne. Najczęściej energia uderzenia przy lądowaniu jest znacząco mniejsza od tej, jaką konstruktorzy zakładają do obliczeń w procesie projektowania.
Dwa przedstawione problemy w projektowaniu podwozi lotniczych mogą zostać rozwiązane dzięki koncepcji nowego podwozia gazowego przedstawionego w tym artykule. Po pierwsze, dzięki zastosowaniu technologii inteligentnych i wykorzystaniu materiału funkcjonalnego stało się możliwe zaprojektowanie amortyzatorów czysto gazowych w podwoziach do aparatów latających, dzięki czemu możliwe jest wyeliminowanie oleju hydraulicznego o znacznie większej gęstości od gazu i efektywne obniżenie ciężaru podwozia samolotu. Po drugie dzięki wprowadzeniu inteligentnego sterowania przepływem gazu w amortyzatorze, stała się możliwa adaptacja rzeczywistych charakterystyk pracy amortyzatora do aktualnej wartości energii uderzenia samolotu o pas startowy.
Artykuł przedstawia wstępną fazę badań koncepcyjnych nad gazowym absorberem uderzeń przeznaczonym od zastosowania w podwoziu aparatu latającego, sterowanym przy pomocy zaworu piezoelektrycznego. W trakcie badań wykonano serię prób na modelu numerycznym, która została zweryfikowana przy pomocy badań eksperymentalnych, do których zaprojektowano i zrealizowano sterowanie w pętli zamkniętej dla szybkiego zaworu piezo elektrycznego zintegrowanego z absorberem gazowym.

Keywords:

podwozia lotnicze, podwozie adaptacyjne, adaptacyjna dyssypacja energii

Affiliations:
Graczykowski C.-IPPT PAN
Mikułowski G.-IPPT PAN
Pawłowski P.K.-IPPT PAN
13.Mikułowski G., Pawłowski P.K., Wołejsza Z., Podwozie lotnicze z adaptacyjnym systemem absorpcji energii, JOURNAL OF AERONAUTICA INTEGRA, ISSN: 1896-8856, Vol.1, pp.125-129, 2007
Abstract:

Podczas każdego lądowania samoloty są narażone na duże przeciążenia dynamiczne mające zdecydowany wpływ na trwałość i niezawodność konstrukcji nośnej. Wielkość przeciążeń, jakim poddawany jest kadłub samolotu, zależy w dużej mierze od poprawnej pracy podwozia lotniczego. Głównym elementem podwozia, który pochłania największą ilość energii kinetycznej związanej z momentem przyziemienia jest amortyzator. Optymalne działanie amortyzatora lotniczego ma decydujący wpływ na zużycie zmęczeniowe materiałów konstrukcyjnych oraz na bezpieczeństwo lądowania.
Wprowadzenie systemu adaptacyjnego, który będzie w stanie modelować charakterystykę dyssypacji po przeprowadzeniu diagnozowania energii kinetycznej związanej z prędkością przyziemienia i ciężarem samolotu, znacznie poprawi efektywność działania amortyzatora lotniczego, zwiększając niezawodność eksploatacyjną konstrukcji i bezpieczeństwo lotu.

Keywords:

podwozia lotnicze, podwozie adaptacyjne, adaptacyjna dyssypacja energii

Affiliations:
Mikułowski G.-IPPT PAN
Pawłowski P.K.-IPPT PAN
Wołejsza Z.-IPPT PAN

List of chapters in recent monographs
1.
343
Skłodowski M., Pawłowski P., Górecka K., Computer Vision and Graphics, ICCVG 2014, rozdział: Geometrical Models of Old Curvilinear Paintings, Springer Verlag, LNCS , pp.578-585, 2014
2.
344
Skłodowski M., Pawłowski P., Monitorowanie obciążeń i stanu technicznego konstrukcji mostowych, rozdział: System monitorowania konstrukcji stadionu, IPPT Reports on Fundamental Technological Research, pp.197-207, 2014
3.
417
Chikahiro Y., Ario I., Nakazawa M., Ono S., Holnicki-Szulc J., Pawłowski P., Graczykowski C., Mobile and Rapidly Assembled Structures IV, rozdział: An Experimental Study On The Design Method Of A Real-sized Mobile Bridge For A Moving Vehicle, N. De Temmerman,Vrije, C.A. Brebbia, WITPress, pp.93-106, 2014
4.
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
5.
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
6.
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
7.
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
8.
196
Pawłowski P.K., Mikułowski G., Graczykowski C., Ostrowski M., Jankowski Ł., Holnicki-Szulc J., Smart technologies for safety engineering, rozdział: Adaptive impact absorption, Wiley, Holnicki-Szulc J. (Ed.), pp.153-213, 2008

Conference papers
1.Chikahiro Y., Ario I., Pawlowski P., Graczykowski C., Nakazawa M., Holnicki-Szulc J., Ono S., Dynamics of the scissors-type Mobile Bridge, EURODYN 2017, X International Conference on Structural Dynamics, 2017-09-10/09-13, Rome (IT), DOI: 10.1016/j.proeng.2017.09.339, No.199, pp.2919-2924, 2017
Abstract:

We have experienced many times a phenomenon in which a bridge is washed away due to a typhoon, heavy rain in the rainy season, localized torrential rain, tsunami, and other flood disasters, or in which a bridge is damaged by an earthquake or a tremor. There is accordingly increasing demand for new technology and science to restore bridges that have been washed away or damaged. The paper presents a new type of emergency bridge, called Mobile Bridge™(MB), which can be quickly constructed in case of damages after a natural disaster. The concept of the bridge is based on the application of scissor-type mechanism, which provides its rapid deployment. Up to now several experimental MBs of different size were constructed and tested. The presented research reviews fundamental numerical and experimental results for the MB version 4.0 (MB4.0). Experimental testing included strain and acceleration measurements in free and forced loading conditions. From these results, it was possible to estimate basic dynamic characteristics of the bridge. Besides, in order to provide a basis for development of new construction methods for structural reinforcement and suppression of vibrations, various numerical analyses were conducted. The conducted research allows for a better and safer design of the movable and foldable full-scale bridge, the MB.

Keywords:

deployable bridge, scissors-type bridge, emergency bridge, light-weight structure, temporary bridge

Affiliations:
Chikahiro Y.-Shinshu University (JP)
Ario I.-Hiroshima University (JP)
Pawlowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Nakazawa M.-Tohoku Gakuin University (JP)
Holnicki-Szulc J.-IPPT PAN
Ono S.-Japan Construction Method and Machinery Research Institute (JP)
2.Graczykowski C., Pawłowski P., Mathematical Modelling of Adaptive Skeletal Structures for Impact Absorption and Vibration Damping, EURODYN 2017, X International Conference on Structural Dynamics, 2017-09-10/09-13, Rome (IT), DOI: 10.1016/j.proeng.2017.09.093, No.199, pp.1671-1676, 2017
Abstract:

The paper describes mathematical modelling of adaptive skeletal structures, which are equipped with semi-active dissipaters based on smart fluids or fast-operating valves and utilize the paradigm of real-time adaptation to external loading. The proposed approach is based on three subsequent stages: i) exact thermodynamic modelling of a single semi-active dissipater with the use of mass, momentum and energy conservation laws, ii) global description of the entire skeletal structure considered as an assembly of semi-active dissipaters in certain geometrical configuration, iii) real-time control of the fluid flow inside semi-active dissipaters providing instantaneous adaptability to actual dynamic loading. This methodology enables accurate representation of mechanical characteristics of the skeletal structure and reliable analysis of its adaptation capabilities.

Keywords:

adaptive structures, skeletal structures, impact absorption, vibration damping

Affiliations:
Graczykowski C.-IPPT PAN
Pawłowski P.-IPPT PAN
3.Pawłowski P., Frąś T., Numerical and experimental investigation of asymmetrical contact between a steel plate and armour-piercing projectiles, LS-DYNA 2017, European LS-DYNA Conference 2017, 2017-05-09/05-11, Salzburg (AT), pp.1-9, 2017
Abstract:

Protection of combat-vehicles against impacts of small-calibre projectiles may be improved by the application of relatively thin and hard steel plates perforated by a plurality of holes. It is observed that due to the contact with a plate,the core of armour-piercing (AP) projectiles may be shattered, partially eroded or rotated, depending on the hit-position. The contact asymmetry is the strongest when a projectile hits a hole edge, its core undergoes bending and tends to fracture. The presented study discusses two methods of modelling of the contact and interactions between a bullet and a steel target. One of them is the explicit Lagrangian simulation of impacts of a fully represented AP projectile, another one is the semi-analytical model based on the integration of the motion equations of a 6 DOF rigid projectile. The results of numerical and semi-analytical approaches are compared with the ballistic impact experiment, in which the defeat mechanisms provided by 4-mm-thick slotted bainitic plates (Pavise™ SBS 600P) against hard-core 7.62 mm P80 0.30 AP x 51 (.308 Win) projectiles were verified, [1].

Affiliations:
Pawłowski P.-IPPT PAN
Frąś T.-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
Abstract:

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.

Keywords:

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

Affiliations:
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.Frąś T., Roth M., Pawłowski P., Thermo-viscoplastic behavior of AA7020-T651 in application for modeling of dynamic loadings, ICCEE 2016, International Conference on Civil and Environmental Engineering, 2016-10-17/10-19, Hiroshima (JP), pp.1-8, 2016
Abstract:

The stress–strain behavior of the rolled AA7020 aluminum tempered in T651 conditions is studied at various strain rates and temperatures. Basing on tensile, shear and compression tests, the effects of strain and strain-rate hardening, thermal softening and plastic anisotropy are discussed. The parameters of the thermo-viscoplastic flow and fracture models proposed by Johnson and Cook are identified and validated basing on the numerical modeling.
The obtained constitutive relations may be applied to model more complex states of stresses resulted from different loading conditions.

Keywords:

AA7020-T651, flow and fracture models, metals under dynamic loadings, numerical simulation of metal deformation

Affiliations:
Frąś T.-IPPT PAN
Roth M.-Giessen University of Applied Sciences (DE)
Pawłowski P.-IPPT PAN
6.Skłodowski M., Pawłowski P., Smartphone aided structural monitoring and measurements, SAHC 2106, Structural Analysis of Historical Constructions, 2016-09-13/09-15, Leuven (BE), pp.140-144, 2016
Abstract:

Environmental and mechanical quantities need to be measured and registered in order to provide engineers and researchers with data required for diagnostics of heritage structures' condition. Analysis of the needs of diagnostic measurements and monitoring of historic structures shows that a large number of structures should be supervised. However hardware costs and resources needed to implement existing technologies constitute a barrier for a wide usage of modern sensors. The presented research shows that everyday usage of smartphones can be extended into a technology suitable for technical diagnostic purposes. Smartphone has many intrinsic sensors factory installed so it is already a sensing device. By calibrating the sensors the smartphone can be upgraded from being a sensing device to become the real measuring equipment. This emerging technology called Smartphone Aided Structural Monitoring and Measurements (SASMM) is not limited to the examples presented in this paper.

Affiliations:
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
7.Graczykowski C., Pawłowski P., Physical Modeling of Magnetorheological Damper, 6WCSCM, 6th World Conference on Structural Control and Monitoring, 2014-07-15/07-17, Barcelona (ES), pp.1-10, 2014
Abstract:

The paper describes enhanced physical model of MR damper which takes into account the effects of blocking the flow between the chambers in case of low pressure difference and the compressibility of the fluid enclosed in each chamber. Combination of both effects is considered as the reason of gene ration of the characteristic shapes of force-velocity hysteresis loops. The subsequent sections of the paper contain derivation of the thermodynamic equations governing response of the damper and their implementation for two constitutive models of the magnetorheological fluid. Successful qualitative comparison against the experiment proves the correctness of applied assumptions and the relevance of the proposed model.

Keywords:

magnetorgeological fluids, MRF dampers, physical-based modeling

Affiliations:
Graczykowski C.-IPPT PAN
Pawłowski P.-IPPT PAN
8.Pawłowski P., Ostrowski M., Graczykowski C., High performance valves for adaptive inflatable structures with flow driven control, SMART2013, 6th ECCOMAS Thematic Conference on Smart Structures and Materials, 2013-09-03/09-06, Turyn (IT), pp.1-10, 2013
Abstract:

The paper presents a concept of new adaptive valve s, which can be applied in the Adaptive Inflatable Structures for impact absorption - high-performance membrane and bistable snap-through valve. The main idea behind those concepts is to employ fluid flow in order to assist actuation of the system.

Keywords:

adaptive impact absorption, inflatable structures, high performance valves

Affiliations:
Pawłowski P.-IPPT PAN
Ostrowski M.-IPPT PAN
Graczykowski C.-IPPT PAN
9.Pawłowski P., Graczykowski C., Holnicki-Szulc J., Ario I., Smart, deployable skeletal structures for safety engineering, SMART2013, 6th ECCOMAS Thematic Conference on Smart Structures and Materials, 2013-09-03/09-06, Turyn (IT), pp.1-10, 2013
Abstract:

This contribution presents the concept of smart, deployable skeletal structures along with existing and prospective applications. The first part introduce s the concept of multi-folding, which is the basis for the design of all smart deployable skeletal structures. In the second part three diverse innovative applications are described: deployable mobile bridge, adaptive impact absorber and controllable valve.

Keywords:

smart skeletal structures, adaptive impact absorption, safety engineering

Affiliations:
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
Ario I.-Hiroshima University (JP)
10.Skłodowski M., Pawłowski P., Wójcicki P., Pilotażowy System Monitorowania Stanu Deformacji Konstrukcji Stadionu Piłkarskiego, XL Ogólnopolskie Sympozjum Diagnostyka Maszyn, 2013-03-04/03-08, Wisła (PL), pp.1-8, 2013
Abstract:

Znaczny rozwój inwestycji wielkogabarytowych obiektów sportowych stworzył potrzebę równoległego rozwoju metod monitorowania bezpieczeństwa stadionów mogących pomieścić dziesiątki tysięcy ludzi. Powszechną cechą eksploatacji wielkich stadionów jest ich wykorzystanie zarówno do organizacji imprez sportowych jak i masowych imprez kulturalnych np. koncertów. Specyfika takich dużych imprez sportowych i kulturalnych niesie w sobie zagrożenia dla konstrukcji na skutek nieprzewidywalnych na etapie projektowania zmian obciążeń wywołanych drganiami i montażem na elementach konstrukcji dodatkowego ciężkiego sprzętu.
Mając na uwadze powyższe uwarunkowania jako cel badań przyjęto opracowanie, wdrożenie i przetestowanie w praktyce światłowodowego systemu monitorowania deformacji konstrukcji stadionu mieszczącego się w Warszawie przy ulicy Łazienkowskiej 3, należącego do WOSiR, a obecnie użytkowanego przez Klub Piłkarski

Keywords:

monitorowanie konstrukcji, systemy FBG, monitorowanie deformacji konstrukcji stadionu

Affiliations:
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Wójcicki P.-IPPT PAN
11.Holnicki-Szulc J., Graczykowski C., Grzędziński J., Mikułowski G., Mróz A., Pawłowski P., Wiszowaty R., Adaptive Impact Absorption - the concept, simulations and potential applications, 4th International Conference on Protection of Structures Against Hazards, 2012-11-15/11-16, , pp.1-16, 2012
Abstract:

Adaptive Impact Absorption focuses on adaptation of energy absorbing structures to actual dynamic loading by using system of sensors detecting and identifying impact in advance and semi -active dissipaters with controllable mechanical properties which enable change of system dynamic characteristics in real time. The article present s a review of research conducted at the Department of Intelligent Technologies of the Institute of Fundamental Technological Research dedicated to applications of systems for Adaptive Impact Absorption. Wide range of presented examples covers pneumatic landing gears, bumpers for offshore towers, wind turbine blade-hub connections and d protective barriers for automotive applications.

Keywords:

adaptive impact absorption, safety engineering, smart structures, optimal control

Affiliations:
Holnicki-Szulc J.-IPPT PAN
Graczykowski C.-IPPT PAN
Grzędziński J.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Pawłowski P.-IPPT PAN
Wiszowaty R.-IPPT PAN
12.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
13.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
14.Sala D., Pawłowski P., Kołakowski P., Wireless transmission system dedicated to SHM of railway infrastructure, EWSHM 2010, 5th European workshop on Structural Health Monitoring, 2010-06-29/07-02, Sorrento (IT), pp.659-664, 2010
Abstract:

In-situ measurements collected with standard cabling suffer from the serious disadvantage of no automation, which implies frequent visits to the monitored structure in order to gather the requested data. For minimizing the man effort involved, a system of wireless transmission (WT) of in-situ collected data has been proposed. Principal ideas of such system should be pretty universal in a number of applications related to structural health monitoring (SHM). However each WT system should be customized for a specific application to provide the best performance. The proposed WT system is dedicated to rail traffic monitoring and SHM of railway bridges. The idea is to design smart sensors to be mounted on the bridge and equipped with electronic modules for short-range wireless transfer of SHM data. The far-range wireless transfer from the local bridge unit to a remote analysis centre will be performed using the GSM technology.

Keywords:

SHM, monitoring of railway bridges

Affiliations:
Sala D.-IPPT PAN
Pawłowski P.-IPPT PAN
Kołakowski P.-IPPT PAN
15.Pawłowski P., Holnicki-Szulc J., Struktury mechaniczne typu harmonijkowego (multifolding) w adaptacyjnych układach dyssypacji energii, XXXVII Ogólnopolskie Sympozjum Diagnostyka Maszyn, 2010-03-08/03-13, Wisła (PL), pp.1-8, 2010
16.Motylewski J., Pawłowski P., Rak M., Zieliński T.G., Identyfikacja źródeł aktywności wibroakustycznej maszyn metodą kształtowania wiązki sygnału (beamforming), XXXVII Ogólnopolskie Sympozjum Diagnostyka Maszyn, 2010-03-08/03-13, Wisła (PL), pp.1-8, 2010
Abstract:

W zagadnieniach identyfikacji i lokalizacji źródeł aktywności wibroakustycznej maszyn, istotnym problemem jest wizualizacja pól rozkładu wielkości akustycznych na wybranych powierzchniach oraz określenie udziału poszczególnych źródeł w bilansie energetycznym sygnału wibroakustycznego maszyny.
Stosowane w wibroakustyce metody formowania wiązki (beamforming) polegają na przestrzenno-czasowym przetwarzaniu sygnału rejestrowanego przez matrycę mikrofonową. Identyfikacja źródła odbywa się poprzez analizę zależności amplitudowo-fazowych sygnałów akustycznych padających na poszczególne przetworniki matrycy.
Ponieważ z metodologicznego punktu widzenia interesujące jest określenie możliwości zastosowania metody kształtowania wiązki w przypadku złożonych urządzeń posiadających źródła o małej aktywności wibroakustycznej, obiektem wstępnych prac był zasilacz hydrauliczny typu Silentflo firmy MTS.
Rezultaty otrzymane w wyniku przeprowadzonych badań w pełni potwierdzają zalety metody beamformingu w określeniu lokalizacji i identyfikacji źródeł aktywności wibroakustycznej maszyn.

Keywords:

Wibroakustyka, Lokalizacja źródeł akustycznych, Beamforming

Affiliations:
Motylewski J.-IPPT PAN
Pawłowski P.-IPPT PAN
Rak M.-other affiliation
Zieliński T.G.-IPPT PAN
17.Mikułowski G., Pawłowski P., Graczykowski C., Wiszowaty R., Holnicki-Szulc J., On a pneumatic adaptive landing gear system for a small aerial vehicle, SMART 2009, 4th ECCOMAS Thematic Conference on Smart Structures and Materials, 2009-07-13/07-15, Porto (PT), pp.1-9, 2009
Abstract:

The class of ultra-light aircraft becomes more and more popular among the enthusiasts of aviation due to low formal requirements of getting the pilot license and low costs of the equipment. Therefore, the training of the pilots starts to be a large-scale task. One of the most difficult operation for the inexperienced pilots is touch-down and it often happens to strike the ground with a high sink speed. In consequence the training machines are endangered of fast structural damage. A potential solution would be to mount a system of adaptive landing gear for light aircraft with a capability of recognition of the actual landing impact and tuning the landing struts in order to conduct the smoothest landing operation possible. In the case of the ultra-light aircraft class the weight of the components is the crucial task and therefore the low-weight pneumatic system is proposed for these application.
The paper presents a concept of an adaptive landing system and adequate control strategy for a small aerial vehicle. The objective of the work was to develop a fully functional model of the landing system and experimental verification of it. The system is based on the new pneumatic impact absorbers actuated via piezo-stacks. The concept assumes designing of the system with the capability of adaptation to actual energy of impact scenario identified by a dedicated sensing system for impact energy recognition.
The designed control system was dedicated to process the data from the system of impact energy recognition in order to perform the optimal landing scenario. The objective of the control strategy was minimization of the structure’s deceleration peaks during the touchdown.
The presented results consist of numerical analysis of the adopted strategy of control and experimental verification of the concept on the dedicated experimental device. The results proved that the proposed method allowed minimization of the maximal deceleration level acting on the demonstrator.

Affiliations:
Mikułowski G.-IPPT PAN
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Wiszowaty R.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN

Conference abstracts
1.Chikahiro Y., Ario I., Adachi K., Shimizu S., Zenzai S., Pawłowski P., Graczykowski C., Holnicki-Szulc J., FUNDAMENTAL STUDY ON DYNAMIC PROPERTY OF SCISSORING BRIDGE FOR DISASTER RELIEF, ENOC 2017, 9th European Nonlinear Dynamics Conference , 2017-06-25/06-30, Budapest (HU), pp.1-2, 2017
Abstract:

The world has seen many kinds of natural disasters, which have critically influenced the residents’ lives by causing damage to infrastructure. To realize rapid rescue efforts in an emergency situation,we propose a deployable emergency bridge, called Mobile Bridge TM [1], based on the theory of foldable structures[2]and the concept of Multi-Folding Microstructures (MFM)[3]. The current research presents the fundamental,numerical and experimental results obtained for the pedestrian and vehicle Mobile Bridges. In this paper, it is considered the localized linearization problem with the fixed an angle although this bridge contains a geometrical nonlinearity of scissors structure.Additionally, a seismic response analysis is conducted for the case where the Mobile Bridge is used in the disaster area as an emergency bridge. This allows for a better and safer structural design of the Mobile Bridge, which is patented in [4],[5].

Affiliations:
Chikahiro Y.-Shinshu University (JP)
Ario I.-Hiroshima University (JP)
Adachi K.-Hiroshima University (JP)
Shimizu S.-Shinshu University (JP)
Zenzai S.-Shinshu University (JP)
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
2.Chikahiro Y., Ario I., Holnicki-Szulc J., Pawłowski P., Graczykowski C., A Study on Optimal Reinforcement of Scissor Type of Bridge with Additional Strut Members, ICCEE 2016, International Conference on Civil and Environmental Engineering, 2016-10-17/10-19, Hiroshima (JP), pp.1-2, 2016
Keywords:

scissor type of bridge, emergency bridge, strut reinforcement, sectional optimization

Affiliations:
Chikahiro Y.-Shinshu University (JP)
Ario I.-Hiroshima University (JP)
Holnicki-Szulc J.-IPPT PAN
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
3.Frąś T., Roth M., Pawłowski P., Thermo-viscoplastic behavior of AA7020-T651 in application for modeling of dynamic loadings, ICCEE 2016, International Conference on Civil and Environmental Engineering, 2016-10-17/10-19, Hiroshima (JP), pp.1-2, 2016
Abstract:

The stress–strain behavior of the rolled AA7020 aluminum tempered in T651 conditions is studied at various strain rates and temperatures. Basing on tensile, shear and compression tests, the effects of strain and strain-rate hardening, thermal softening and plastic anisotropy are discussed. The parameters of the thermo-viscoplastic flow and fracture models proposed by Johnson and Cook are identified and validated basing on the numerical modeling.
The obtained constitutive relations may be applied to model more complex states of stresses resulted from different loading conditions.

Keywords:

AA7020-T651, flow and fracture models, metals under dynamic loadings, numerical simulation of metal deformation

Affiliations:
Frąś T.-IPPT PAN
Roth M.-Giessen University of Applied Sciences (DE)
Pawłowski P.-IPPT PAN
4.Pawłowski P., Graczykowski C., Ostrowski M., Sekuła K., Mróz A., Controllable high performance valves for improved crashworthiness of inflatable structures, PETER 2015, Annual International Workshop on Dynamic Behaviour of Structures and Materials, Interaction and Friction Across the Strain Rates, 2015-08-26/08-28, London (GB), pp.52-53, 2015
Keywords:

adaptive inflathigh performance valves, adaptive inflatable structures

Affiliations:
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Ostrowski M.-IPPT PAN
Sekuła K.-other affiliation
Mróz A.-IPPT PAN
5.Ostrowski M., Pawłowski P., Exploding wire technology for control of structure subjected to low velocity impact, PETER 2015, Annual International Workshop on Dynamic Behaviour of Structures and Materials, Interaction and Friction Across the Strain Rates, 2015-08-26/08-28, London (GB), pp.25, 2015
Abstract:

Control of crash or impact process may be based on change of mechanical characteristics due to modification of inner structural connections. Presented work covers numerical and experimental analysis of sandwich fabric composite cantilever beam subjected to a low velocity impact. A set of metallic electrical conductors was placed between composite layers causing their controlled delamination when subjected to an electrical explosion. In result, separation of initially connected components in the vicinity of the exploded conductor is obtained, leading to the change of global mechanical characteristics, allowing for modification of beam behavior. Exploding bridge wire (EBW) phenomenon is known from the end of the 18th century [1] and being in use today, mainly for ignition of high explosive materials [2] as well as in physics of high energy [3]. This effect is caused by a rapid heating of a conductor subjected to a pulse of high voltage electric current, what changes its state of matter from solid to vapor, expanding in surrounding continuum and forming a strong pressure wave. Afterwards, in result of current discharge through the formed plasma channel, additional heat is applied to the system increasing the effect. Depending on explosion parameters and properties of continuum elastic, elasto-plastic or shock waves can be observed. In case of action on the composite, exploding wire embedded between layers acts on adjacent surfaces causing their progressive separation in the vicinity of the explosion. Delamination decoupling adhesive is being extended by the pressure acting in the direction normal to the surface of the composite. Figure 1 depicts an example of experimental delamination process from a medium voltage EBW system. A cantilever beam made of layered sandwich composite was modelled with shell finite elements. Problem was solved in a commercial FEM LS-DYNA package using explicit time integration with nonlinear material and geometric formulation. The delamination was simulated by a controlled separation of a connection between layers in the area surrounding the predefined location of the EBW wire. The initiation time of layers’ separation was one of controllable parameters allowing for a wide search for solution dependencies. Numerical solution was compared with experimental results, showing good convergence and proving control feasibility. Also an analytical, rigid perfectly plastic model for explanation of first order effects was used for demonstration of governing principles [4].

Keywords:

Exploding bridge wire

Affiliations:
Ostrowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
6.Holnicki-Szulc J., Faraj R., Graczykowski C., Jankowski Ł., Mikułowski G., Mróz A., Ostrowski M., Pawłowski P., Wiszowaty R., Adaptive impact absorption - potential applications for safety engineering, SMART 2015, 7th ECCOMAS Thematic Conference on Smart Structures and Materials, 2015-06-03/06-05, Ponta Delgada (PT), pp.1-2, 2015
Keywords:

Smart And Adaptive Structures, Adaptive Impact Absorption, Safety Engineering

Affiliations:
Holnicki-Szulc J.-IPPT PAN
Faraj R.-IPPT PAN
Graczykowski C.-IPPT PAN
Jankowski Ł.-IPPT PAN
Mikułowski G.-IPPT PAN
Mróz A.-IPPT PAN
Ostrowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Wiszowaty R.-IPPT PAN
7.Skłodowski M., Pawłowski P., Górecka K., Wójcicki P., Stretching of Curvilinear Canvas of Religious Paintings, 6th European Symposium on Religious Art Restoration and Conservation, 2014-06-09/06-11, Florencja (IT), pp.149-152, 2014
Abstract:

Religious art objects preserved in the form of curved canvas paintings present a very interesting subject for the research, both from technical and conservation points of view. The work concentrates on theoretical and experimental analysis of mechanically correct stretching of curvilinear canvas to avoid folding and buckling of paintings. It is shown that treating curvilinear canvas as a ruled surface might be a very promising solution. Reverse engineering can help to discover the ruled surface shape adequate to the individual curved painting.

Keywords:

canvas, stretching, ruled surface, religious paintings

Affiliations:
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Górecka K.-Academy of Fine Arts in Warsaw (PL)
Wójcicki P.-IPPT PAN
8.Górecka K., Skłodowski M., Pawłowski P., Szpor J., New Materials and Methods Used in the Conservation of the XVII Century Curvilinear Canvas Canvas Painting , 6th European Symposium on Religious Art Restoration and Conservation, 2014-06-09/06-11, Florencja (IT), pp.199-202, 2014
Abstract:

Paper discusses a concept and conservation methodology of the XVIIIth century curvilinear canvas painting “Adoration of the Magi” from the Saint – Aubain Cathedral church in Namur (Belgium). Atypical form of the painting bowed in the horizontal plane, adapted to the apse wall and its very large size (3.70 x 4.50 m) required using some innovative technologies and materials. The basic premise of the conservation process was a detailed analysis of the canvas shape and its preservation on each step of the conservation works. The concept required construction of two curved platforms: concave and convex. The new system of the canvas overturning was also designed. An innovative method of strengthening of the canvas during lining process in vertical direction by using Kevlar fibres was applied. Required strengthening and modification of the stretching frame is also discussed.

Keywords:

curvilinear, large-size canvas painting, lining, stretching, Kevlar fibres

Affiliations:
Górecka K.-Academy of Fine Arts in Warsaw (PL)
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Szpor J.-Academy of Fine Arts in Warsaw (PL)
9.Pawłowski P., Graczykowski C., Holnicki-Szulc J., Bistable Elements for Application in Controllable High Performance Valves, 6WCSCM, 6th World Conference on Structural Control and Monitoring, 2014-07-15/07-17, Barcelona (ES), pp.1, 2014
Keywords:

high performance valve, bistable elements, snap-through, adaptive impact absorption

Affiliations:
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
Holnicki-Szulc J.-IPPT PAN
10.Chikahiro Y., Ario I., Nakazawa M., Ono S., Holnicki-Szulc J., Pawłowski P., Graczykowski C., Structural Analysis and Experimental Study for realsized MB Travelable Vehicles, ENOC 2014, 8th European Nonlinear Dynamics Conference, 2014-07-06/07-11, Wiedeń (AT), pp.1-2, 2014
Abstract:

Many natural disasters such as earthquakes, floods, torrential rains occur around the world, and we to undertake quick rescue actions. However, there are many recovery problems because of the occurrence of secondary disasters at each rescue worksite.So, from the previous study of optimal structures and control regulation of MFM[1]-[2], we propose a new type of foldable bridge with scissors structure called Mobile Bridge[3]. Applying scissors mechanism to bridge form, Mobile Bridge provides not only mobility but also good structural performance, because the whole bridge can be expand or fold quickly. In this paper, we discuss the vehicles passing test on the real scale Mobile Bridge in order to evaluate the design method and application limits.

Keywords:

Mobile Bridge, deployable structures, temporary bridges, scissors-type structures

Affiliations:
Chikahiro Y.-Shinshu University (JP)
Ario I.-Hiroshima University (JP)
Nakazawa M.-Tohoku Gakuin University (JP)
Ono S.-Japan Construction Method and Machinery Research Institute (JP)
Holnicki-Szulc J.-IPPT PAN
Pawłowski P.-IPPT PAN
Graczykowski C.-IPPT PAN
11.Skłodowski M., Pawłowski P., Posenato D., FBG System for Monitoring of Dynamic Loads Caused by Cheering During Football Competitions, SMART2013, 6th ECCOMAS Thematic Conference on Smart Structures and Materials, 2013-09-03/09-06, Turyn (IT), pp.1-2, 2013
Abstract:

Nowadays large stadium structures are designed for assumed static loads and it is difficult to calculate important influence of real stresses resulting from dynamic loads caused by moving crowds. The paper presents Structural Health Monitoring System, based on multiplexed Fiber Bragg Grating sensors. They are used to measure strains and temperature of structural elements and allow us to measure dynamic deformations to observe changes in structural behaviour of the stadium during cheering on a football competition and calculate instantaneous anthropogenic loads.

Keywords:

Structural Health Monitoring, FBG sensors, monitoring of concrete structures

Affiliations:
Skłodowski M.-IPPT PAN
Pawłowski P.-IPPT PAN
Posenato D.-SMARTEC SA (CH)
12.Holnicki-Szulc J., Graczykowski C, Pawłowski P., Ario I., High Performance Valve for Adaptive Pneumatic Impact Absorbers, SolMech 2012, 38th Solid Mechanics Conference, 2012-08-27/08-31, Warszawa (PL), pp.1-2, 2012
Abstract:

Dissipation of the energy in mechanical systems is a vitally important engineering and scientific problem. Current stringent safety requirements enforce substantial change of methods of structural design and application of new solutions and technologies which ensure structural integrity.
Currently applied passive safety systems are typically not equipped with control devices. Their dynamic characteristics remains unaltered and thus it is well adjusted to a narrow range of actual loadings. In case of impact loading, it is highly advantageous to apply systems of Adaptive Impact Absorption (AIA), which are capable of fast change of the dynamic characteristics. Recent fast development of the material technologies and, in particular, development in the field of functional (smart) materials and electronic measurement and control systems had created new possibilities of practical applications of the AIA systems.
During the adaptation process the choice of optimal control strategy is followed by adjustment of the dynamic characteristics of adaptive elements of the absorber. These elements can entirely made of functional materials (as e.g. shape memory alloys) or, alternatively, they can be equipped with controllable devices, so-called structural fuses, which provide controlled response of the element. Depending on type of applied control, the changes of structural parameters occur only once (usually before impact) or they are controlled in real time during the impact process.
The systems of Adaptive Impact Absorption can be effectively used to increase the level of safety during the action of the impact loading. In particular, very promising results are obtained with the use of adaptive inflatable structures. However, the possibilities of their practical applications are limited due to the lack methods allowing for the efficient and fast control of the gas flow during impact.
The presented work focuses on the pneumatic adaptive impact absorbing system equipped with a novel, high performance valve, which utilizes bistable snap-through effect. Snap-through effects are mainly the subject of theoretical analysis and they do not find many practical engineering applications.

Keywords:

smart structures, high performance valves, adaptive pneumatic systems, adaptive impact absorption

Affiliations:
Holnicki-Szulc J.-IPPT PAN
Graczykowski C-IPPT PAN
Pawłowski P.-IPPT PAN
Ario I.-Hiroshima University (JP)

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pdf
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