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Pierwszy krok w kierunku normalizacji konstrukcji betonowych wykonywanych w technologii druku 3D

Sikora Paweł, Federowicz Karol, Skibicki Szymon, Techman Mateusz, Hoffmann Marcin, Ludwiczak-Sarzała Aleksandra, Chougan Mehdi, Pacheco Joao

Przegląd Budowlany

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2024

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R. 95, nr 5

146--152

PL

Technologia wytwarzania przyrostowego (druku 3D) z kompozytów cementowych znajduje zastosowanie w prefabrykacji elementów budowlanych oraz w konstrukcji całych obiektów, takich jak domy i mosty. Ta nowatorska metoda przyczynia się do redukcji kosztów produkcji i skrócenia czasu budowy. Kluczowa jest jednak normalizacja i standaryzacja procesów, by w pełni wykorzystać potencjał technologii. Artykuł omawia amerykańskie kryteria akceptacji ICC-ES AC509, które ustalają wytyczne do projektowania, badania i wykonania ścian drukowanych 3D. Dokument ten określa kryteria akceptacji, uwzględniając właściwości materiałowe, trwałość, analizę statyczną i kontrolę jakości. Przedstawiono również wymogi dotyczące mieszanki cementowej, takie jak konsystencja, czas przydatności do druku, wytrzymałość, mrozoodporność i skurcz. Kryteria zawierają także wskazówki dotyczące współczynnika bezpieczeństwa w projektowaniu, rodzajów badań wytrzymałościowych dla ścian oraz stosowanego zbrojenia. Ponadto obejmuje kwestie związane z badaniem połączenia ściany drukowanej ze stropem, co jest kluczowe dla zapewnienia integralności strukturalnej budynków.

EN

Additive manufacturing technology (3D printing) with cement composites is applied in the prefabrication of building elements and in constructing entire structures, such as houses and bridges. This innovative method contributes to reducing production costs and shortening construction time. However, the normalization and standardization of processes are crucial to fully exploit the technology’s potential. The article discusses the American acceptance criteria ICC-ES AC509, setting guidelines for designing, testing, and executing 3D printed walls. This document defines acceptance criteria, considering material properties, durability, static analysis, and quality control. It also presents requirements for the cement mixture, such as consistency, printability, strength, freeze-thaw resistance, and shrinkage. The standard includes safety factor guidelines for design, types of strength tests for walls, and reinforcement application. Additionally, it covers issues related to testing the connection between the printed wall and the ceiling, vital for ensuring the structural integrity of buildings.

2

Badania techniką spektroskopii Ramana zmiany struktury wybranych macerałów węgla brunatnego w procesie zgazowania

Bielowicz Barbara

Przemysł Chemiczny

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2019

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T. 98, nr 2

241--245

PL

Za pomocą spektroskopii Ramana zanalizowano zmianę struktury macerałów węgla brunatnego zachodzącą w trakcie fluidalnego zgazowania węgla w atmosferze CO₂. Do badań wytypowano macerały w węglu i ich odpowiedniki w karbonizacie. Otrzymane widma Ramana poddano dekonwolucji na dwa pasma G i D₁. Oznaczono ich liczbę falową, intensywność i szerokość połówkową, a także iloczyny ID1/IG oraz AD1/AG. Stwierdzono wyraźne różnice wartości badanych parametrów dla węgla i karbonizatu. W karbonizacie pasmo G jest przesunięte w stronę wyższej liczby falowej, a pasmo D₁ w stronę niższej. Najmniejsze różnice zaobserwowano dla pary fuzynit-fuzynoid, a największe dla pary densynit-inertoid. Szerokość połówkowa dla obu pasm jest mniejsza w karbonizacie. Stosunek intensywności pasm D₁ i G jest większy w karbonizacie. Na podstawie badań spektralnych stwierdzono wyższy stopień aromatyzacji i uporządkowanie struktury w karbonizacie niż w węglu brunatnym.

EN

Lignite from Szczerców deposit and its carbonizate were analyzed by Raman spectroscopy. Spectral parameters of lignite macerals and carbonizate (wave no., intensity, half width, intensity ratio) differed signicantly. The carbonizate had a higher degree of aromatization and a more ordered structure than the lignite.

3

Fabrication of screens for electromagnetic fields shielding with threats analysis at the position

Spilka M., Kania A., Griner S.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 62, nr 1

38--44

EN

Purpose: The aim of this article is to pay attention on the necessary of protection of the people and devices from the harmful electromagnetic radiation. The special role play the screens (materials or systems) for shielding which have a very diversified construction depending on the frequency of electromagnetic fields. Design/methodology/approach: In the paper a problem of electromagnetic fields shielding was presented. Moreover, the occupational risk assessment at the vacuum sublimation position was showed. Findings: The screening methods and materials used for screens were discussed. The threats occurring at the vacuum sublimation position and the preventive actions decreasing the risk level were presented. Research limitations/implications: The paper presents the one of the methods for screens fabrication – vacuum sublimation in a simple laboratory vacuum sublimation equipment. The structure testing and investigation of thickness of fabricated screen (constructed from four layers: aluminum – polypropylene – aluminum – metallic glass of Metglas type) were carried out. The occupational risk assessment was made by three-stage scale method according to PN-N-18002 standard. Practical implications: The results of microscopic observation of fabricated material system unequivocally reject the vacuum sublimation method using a laboratory vacuum sublimation equipment for the screens fabrication. Originality/value: In the article the different kinds of threats occurring at the vacuum sublimation position were presented. The various preventive actions were proposed.

4

Modal frequency shift analysis for prestressed concrete beams developed by integrity loss

Zielnica J., Barczewski R.

Vibrations in Physical Systems

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2008

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Vol. 23

441--446

EN

The paper presents a method of initial analysis of the modal parameter change (e.g. modal frequency shift) due to progressive integrity loss for prestressed concrete beams (sensitivity analysis). A global rescaling method of the numerical modal frequency set was proposed in order to fit the real vibration components determined experimentally. The aim of simulation is numerical determination of frequency modal components and modes for specific boundary conditions, determined by the tested element support system. On the basis of static and dynamic FEM simulation results the optimal location of excitation points, location of transducers recording structure vibration response can be determined. The presented methodology can be helpful and is necessary for determination of possibilities of application of VA methods for testing the prestressed concrete structures.

5

Research of the dynamic properties of structures the models of interpretation

Wiśniowski W.

Journal of KONES

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2008

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Vol. 15, No. 3

561-565

EN

Experimental research of the dynamic properties of structures is performed during of prototype perfectioning, current exploitation and even after the withdrawal from the exploitation for the estimation of the residual durabilities. The aim for research of the dynamic properties of structures is the assurance of its safety, reliability, economic management and comfort. Researcher records the amplitudes of vibrations in the function of the actuation frequencies. Local raise of the amplitude is qualified as resonance. From the researcher point of view, the shape of resonance curves justifies the discrimination of two types of phenomena's: „single resonance" and „close frequencies resonance". For better understanding of these occurrences „the models of interpretation" were proposed. Up to three models of interpretation were assigned to the single resonance: one-degree-of-freedom system, one-degree-of-freedom system with share of the backlashes, two one-degree-of-freedom systems with the same frequencies. From above reasoning, the conclusion results that researcher can expect that the preliminary isolated single resonance belongs to one from the three, mentioned above cases. The judgment of these occurrences, just as the disentanglement of relations in the resonance pair with close frequencies, determines next challenge for the researcher.