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Analiza numeryczna ściany szczelinowej wykonanej w iłach formacji poznańskiej z wykorzystaniem wybranych programów MES

M. Superczyńska A. Zbiciak K. Józefiak
Archives of Civil Engineering | 2016 | Numerical analysis of diaphragm wall model executed in Poznań clay formation applying selected FEM codes | No 3 | 207-224
Keywords Poznań clay formation Constitutive modelling FEM Computational geotechnics Diaphragm wall
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Abstract

The paper presents results of numerical calculations of a diaphragm wall model executed in Poznań clay formation. Two selected FEM codes were applied, Plaxis and Abaqus. Geological description of Poznań clay formation in Poland as well as geotechnical conditions on construction site in Warsaw city area were presented. The constitutive models of clay implemented both in Plaxis and Abaqus were discussed. The parameters of the Poznań clay constitutive models were assumed based on authors’ experimental tests. The results of numerical analysis were compared taking into account the measured values of horizontal displacements.

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Authors and Affiliations

M. Superczyńska
A. Zbiciak
K. Józefiak

Measurement of Membrane Displacement with a Motionless Camera Equipped with a Fixed Focus Lens

Krzysztof Murawski
Metrology and Measurement Systems | 2015 | vol. 22 | No 1 | 69-78 | DOI: 10.1515/mms-2015-0011
Keywords measurement based on fuzzy signal diaphragm displacement image processing motion sensor
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Abstract

The paper presents a technique for measuring membrane displacements with one motionless camera. The method consists in measuring the distance to an object based on one image obtained from a motionless camera with a fixed-focus lens. The essence of the proposed measurement technique is to determine changes of the distance between a membrane and a video camera based on analysis of changes in the focus view of a marker placed on the membrane plane. It is proven that the used technique allows to monitor the frequency and amplitude of the membrane vibration. The tests were performed for the oscillation frequency in the range from 0.5 Hz to 6 Hz and deviations from the neutral position in the range of ±3 mm.
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Authors and Affiliations

Krzysztof Murawski

Electroacoustic Analysis of a Controlled Damping Planar CMOS-MEMS Electrodynamic Microphone

Farès Tounsi Brahim Mezghani Libor Rufer Mohamed Masmoudi
Archives of Acoustics | 2015 | vol. 40 | No 4 | 527-537 | DOI: 10.1515/aoa-2015-0052
Keywords MEMS sensor acoustical model monolithic electroacoustic microphone suspended diaphragm lumped element modeling
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Abstract

This paper gives a detailed electroacoustic study of a new generation of monolithic CMOS micromachined electrodynamic microphone, made with standard CMOS technology. The monolithic integration of the mechanical sensor with the electronics using a standard CMOS process is respected in the design, which presents the advantage of being inexpensive while having satisfactory performance. The MEMS microphone structure consists mainly of two planar inductors which occupy separate regions on substrate. One inductor is fixed; the other can exercise out-off plane movement. Firstly, we detail the process flow, which is used to fabricate our monolithic microphone. Subsequently, using the analogy between the three different physical domains, a detailed electro-mechanical-acoustic analogical analysis has been performed in order to model both frequency response and sensitivity of the microphone. Finally, we show that the theoretical microphone sensitivity is maximal for a constant vertical position of the diaphragm relative to the substrate, which means the distance between the outer and the inner inductor. The pressure sensitivity, which is found to be of the order of a few tens of μV/Pa, is flat within a bandwidth from 50 Hz to 5 kHz.
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Authors and Affiliations

Farès Tounsi
Brahim Mezghani
Libor Rufer
Mohamed Masmoudi

An application of reinforced concrete vaulted slabs and rafts in deep excavation works

Grzegorz Kacprzak Tomasz Daktera Andrzej Stańczyk Urszula Tomczak Seweryn Bodus Michał Werle
Archives of Civil Engineering | 2021 | vol. 67 | No 3 | 61-75 | DOI: 10.24425/ace.2021.138043
Keywords metro station construction urban construction construction stages soil-structure interaction diaphragm wall vaulted slab deep excavation
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Abstract

The overall efficiency of a construction of a deep excavation urban project does not depend only on the duration of the construction but also on its influence on the urban environment and the traffic [9, 10]. These two things depend greatly on the excavation method and the construction stages defined during the design process. This paper describes the construction stages of three metro stations (two stations in Warsaw and one in Paris) and discusses their advantages and disadvantages including among other things its impact on neighbouring infrastructure and the city’s traffic. An important conclusion drawn from this analysis is that the shape of the slabs used can considerably affect the design and the construction stages. For example, a vaulted top slab allows an almost immediate traffic restoration and a vaulted bottom raft allows a much shorter dewatering period.
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Bibliography

[1] A. Stańczyk, “Doświadczenia z budowy stacji metra "Ratusz" i "Marymont" w Warszawie”, Inżynieria i Budownictwo, 5, pp. 244–247, 2008.
[2] Daktera, T., Bourgeois, E., Schmitt, P., Jeanmaire, T., Delva, L., & Priol, G., “Design of deep supported excavations: comparison between real behavior and predictions based on the subgrade coefficient method”, Proceedings of the XVII European Conference on Soil Mechanics and Geotechnical Engineering, pp. 2608–2615, 2019.
[3] Daktera T. “Amélioration des méthodes de calcul des écrans de soutènement à partir du retour d'expérience de grands travaux récents » PhD Thesis, Univ Gustave Eiffel, (to be published) 2020.
[4] M. Graff, “Subway in Warsaw”, Transport systems, 12, pp. 25–35, 2018.
[5] K.F. Unrug, “Shaft design criteria”, International Journal of Mining Engineering, 2, 141–155, 1984.
[6] ILF CONSULTING ENGINEERS, “Design and construction of the underground line II from “Rondo Daszyńskiego” station to the “DworzecWileński” station in Warsaw”, 2010.
[7] M. Mitew-Czajewska, “Geotechnical investigation and static analysis of deep excavation walls – a case study of metro station construction in Warsaw”, Ann. Warsaw Univ. Life Sci. – SGGW, Land Reclam. 47 (2), pp. 163–171, 2015. http://doi.org/10.1515/sggw-2015-0022
[8] A. Sieminska-Lewandowska, “Budowa obiektu a obudowa wykopu – niełatwe zależności”, Nowoczesne Budownictwo Inżynieryjne, marzec kwiecień, pp. 64–71, 2010.
[9] A. Siemińska-Lewandowska, “Głębokie wykopy. Projektowanie i wykonawstwo.”, WKŁ, Warszawa, 2010.
[10] G. Kacprzak, S. Bodus, “The modelling of excavation protection in a highly urbanised environment”, Technical Transactions, Vol. 1, pp. 133–142, 2019. https://doi.org/10.4467/2353737XCT.19.009.10049
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Authors and Affiliations

Grzegorz Kacprzak
1
ORCID: ORCID
Tomasz Daktera
2
ORCID: ORCID
Andrzej Stańczyk
3
ORCID: ORCID
Urszula Tomczak
1
ORCID: ORCID
Seweryn Bodus
3
ORCID: ORCID
Michał Werle
3
ORCID: ORCID
  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
  2. Soletanche Bachy International 280 Avenue Napoléon Bonaparte, 92500 Rueil Malmaison, France
  3. Warbud S.A.

Development and implementation of robotized wire arc additive repair of a gas turbine diaphragm

Piotr Steckowicz Paweł Pyrzanowski Efe Bulut
Bulletin of the Polish Academy of Sciences Technical Sciences | 2024 | 72 | 2 | e147920 | DOI: 10.24425/bpasts.2023.147920
Keywords WAAM diaphragm gas turbines CMT robotic additive repair arc welding Ni-Resist
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Abstract

The current practice of reconstruction of oxidized turbine parts (due to hot corrosion) using arc welding methods facilitates restoration of the nominal shapes and dimensions, as well as other attributes and features. Intense development of 3D additive methods and techniques contributes to the repair/modification of different parts including gas turbine (GT) hardware. The article proves the viability of the concept of using a robotized additive arc welding metal active gas (MAG) process to repair and modify gas turbine diaphragms using different filler materials from the substrate. The industrialized robotic additive process (hybrid repair) shows that very good results were achieved if the diaphragm is cast of nickel-iron and the filler material for welding the passes is austenitic stainless steel (for instance 308 LSi). This is one of the novelties introduced to the repair process that was granted a patent (US11148235B2) and is already implemented in General Electric Service Centers.
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Authors and Affiliations

Piotr Steckowicz
1
ORCID: ORCID
Paweł Pyrzanowski
2
ORCID: ORCID
Efe Bulut
3
  1. GE Power Sp. z o.o. – Oddział Engineering Innovation Center w Warszawie, Al. Krakowska 110/114, 02-256 Warsaw, Poland
  2. Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics, ul. Nowowiejska 24, 00-665 Warsaw, Poland
  3. GE Marmara Technology Center Müh. Hiz. Ltd. Sti. Tubitak-Mam Teknoloji Serbest Bolgesi, 41400, Gebze/Kocaeli, Turkey

Risk of emergency situations of underground objects in the perspective of multi-criteria decision making

R. Dachowski K. Gałek
Archives of Civil Engineering | 2019 | Vol. 65 | No 2 | 149-162
Keywords open caisson sinking diaphragm wall REMBRANDT multi-criteria decision making underground objects
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Abstract

The diaphragm wall and the open caisson represent two main competitive technologies used in the construction of underground objects. In modern times, diaphragm walls are primarily applied for large-size objects, with open caissons being preferred in the case of small-sized ones. Currently, objects of this type are designed mainly for sewage treatment plants and detention reservoirs. Their construction involves highly labour-intensive processes. During the execution of works unforeseen negative effects are observed to occur. During the underground objects construction the most common phenomena are: deviations from the vertical (tilt), sagging, sinking below the designed level, cracking, scratches or leakage through the wall. The purpose of the paper is to classify undesired risk factors emerging in the process of underground objects construction and selection of the optimal technological and material solution for municipal facilities. The implementation of this task involved the selection of Multi-Criteria Decision Making methods, taking into account the cause-effect rating, as the mathematical apparatus. The Ratio Estimation in Magnitudes or deciBells to Rate Alternatives which are Non-DominaTed (REMBRANDT) method was applied. The research proved that it is possible to analytically assess unforeseen risk factors conducive to emergency situations during the implementation of underground objects, using the REMBRANDT method.

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Authors and Affiliations

R. Dachowski
K. Gałek

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