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Algorithm for detection of wave packets in a circular waveguide

Wrzeciono Piotr, Szymański Michał, Bayat Hydayatullah

Vibrations in Physical Systems

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2024

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Vol. 35, nr 1

art. no. 2024111

EN

This paper presents an algorithm for detecting wave packets in a circular waveguide. The waveguide terminated with a concrete plug was used to test the method. The concrete was made in accordance with the Eurocode standard. During the tests, a significant difference was observed between the behavior of the speaker and the concrete plug. The pulse reflected from the plug maintained its shape regardless of the sound level. The reflection of the pulse from the speaker's diaphragm resulted in a significant change in the form and duration of the wave packet. These changes were dependent on the sound level of the wave packet. As a result of these modifications was a significant difference between the measurement uncertainty of detecting a pulse reflected from the concrete and the speaker. In the case of reflection from the speaker, an uncertainty of 0.036% was obtained. The smallest measurement error value for the pulse reflected from the speaker was 2.5%.

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Wpływ stopnia zbrojenia i średnicy prętów na odkształcenia trwałe w belkach wykonanych z betonu o wysokiej wytrzymałości

Bayat Hydayatullah, Ubysz Andrzej

Przegląd Budowlany

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2024

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R. 95, nr 7

35--38

PL

Na podstawie badań doświadczalnych wykonanych na belkach w skali półnaturalnej z betonu o wysokiej wytrzymałości pokazano, jak stopień zbrojenia i średnica stalowych prętów zbrojeniowych wpływają na wartości rezydualnych ugięć belek przy jej cyklicznych obciążeniach. Badania przeprowadzono na 4 seriach belek, w których na poszczególnych poziomach obciążenia pomierzono ugięcia całkowite i pozostające w zależności od poziomu wytężenia belki. Wyniki pokazano w postaci stosunku ugięć resztkowych do całkowitych w zależności od wartości obciążenia. Zmiana stosunku deformacji dla każdego zestawu belek jest analizowana pod kątem wymuszających cykli obciążeń na podstawie założeń sprężysto-plastycznego modelu betonu. Artykuł przedstawia również analizę dotychczasowych wyników badań opisanych w literaturze oraz wniosków autorów, które mają na celu ulepszenie współpracy betonu i stali dla betonów o wysokiej wytrzymałości.

EN

Based on experimental studies conducted on semi-natural scale beams made of high-strength concrete, it has been shown how the degree of reinforcement and the diameter of the steel reinforcing bars influence the values of residual deflections of beams under cyclic loads. The research was carried out on 4 series of beams, in which total and residual deflections were measured at different load levels, depending on the degree of beam stress. The results are presented in the form of the ratio of residual deflections to total deflections in relation to the load value. The change in the deformation ratio for each set of beams is analysed in terms of the imposed load cycles based on the assumptions of a elastic-plastic model of concrete. The article also presents an analysis of existing research results described in the literature, as well as the authors’ conclusions aimed at improving the interaction between concrete and steel for high-strength concretes.

3

The cyclic load effect on the elasticity and plasticity deformation of high-strength reinforced concrete elements

Bayat Hydayatullah, Chalecki Marek, Lesniewska Aleksandra, Maj Marek, Rybak Jarosław, Ubysz Andrzej

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e135, 2024

EN

This article investigates the degradation of stiffness in high and standard-strength concrete due to the influence of repeated loading and considers the non-linear behavior arising from localized or natural defects of concrete. The article also refers to the models from existing literature that evaluate the characteristics of concrete by enhancing its physicochemical properties through the application of natural and synthetic fibers. The impact of the service load, which influences the change in concrete stiffness, is illustrated using the elastic-plastic concrete model. The elastic-plastic model of concrete, combined with experimentally determined data such as elastic and residual deformations, simplifies the analysis of concrete beams or surface elements. This model enables static solutions of inelastic materials based on the classical theory of elasticity. The degradation of element stiffness in this model is described by the local increment of the rotation angle. Based on the model we can assume a constant stiffness along the length of the beam before as well as after exceeding the value of the cracking moment. In the case of cyclic loads, it can be assumed that residual deformations have the greatest influence on the displacement values, which in the calculation model are described by the component of the angle of rotation in the crack, describing permanent displacements.