Yazar "Demirci, Mustafa" seçeneğine göre listele

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  • Küçük Resim Yok
    Öğe
    Prevention of Wave Propagation via Circular Arrangement of Seismic Metamaterials Formed with Concrete Piles
    (Mdpi, 2023) Kacin, Selcuk; Ozturk, Murat; Sevim, Umur Korkut; Karaaslan, Muharrem; Akgol, Oguzhan; Ozer, Zafer; Demirci, Mustafa
    It is known that the low frequencies of seismic surface waves have a destructive effect. The main purpose of seismic metamaterials is to protect structures from seismic waves at low frequencies, especially in a wide band. In this study, the effects of seismic metamaterials formed using circular array concrete piles on surface waves were investigated. Each concrete pile has been selected due to symmetric properties to investigate the band diagram. Therefore, the direction independence can also be determined with respect to frequency. This study was conducted both numerically and experimentally in the low-frequency range of 5-15 Hz. Two fields, with and without metamaterials, have been designed and compared. In numerical analysis, transmission loss graphs were drawn using the finite element method (FEM), and wave propagation at frequencies where the loss happened was simulated. In numerical analysis, optimum dimensions such as radius and depth were determined, and these dimensions were applied exactly in the experimental field. The results obtained from the experiment using a harmonic vibration device are mapped. In this numerical and experimental study, it has been revealed that the proposed structure prevents the propagation of seismic surface waves.
  • Küçük Resim Yok
    Öğe
    Sinusoidally located concrete metastructures for attenuation of seismic surface vibrations
    (Springer, 2023) Kacin, Selcuk; Ozturk, Murat; Sevim, Umur Korkut; Karaaslan, Muharrem; Akgol, Oguzhan; Ozer, Zafer; Demirci, Mustafa
    In this numerical and experimental study, we designed sinusoidal located concrete-based boreholes which are candidate for seismic shielding applications. To attenuate seismic wave transmission in an area, proposed design is created in most dangerous part of seismic frequencies which corresponds 1-15 Hz band. Firstly, transmission loss characteristics of proposed design is obtained numerically, and it is clearly shown that proposed design has multiband blocking capability. Afterwards, total surface displacements were plotted, analysed and explained. Thus, proposed design attenuates seismic wave transmission according to numerical results. Moreover, to support proposed design, various experimental measurements were carried out by using a harmonic vibration source and 14 accelerometers as sensors. Experiments conducted in time domain and obtained results were converted to the frequency domain by fast Fourier transform, and mapping processes were done by interpolation technique. The obtained measured map of the seismic radiation between 5 and 15 Hz bands is given, and a good matching between simulations and experiments has been seen. As obtained numerical and experimental results, the proposed metamaterial structure could be used in seismic shielding applications because of its highly blocking capability of seismic wave transmission.