Browsing by Author "Zhang, Xihong"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    33
    (33, 33) Hernández Prado, Francisco Javier; Contreras, Nicolás; Zhang, Xihong; Hao, Hong; 33
    Interlocking bricks have emerged as a promising alternative to traditional masonry, primarily due to their self-aligning capabilities, which accelerate construction and reduce dependency on skilled labour—advantages particularly valuable for addressing Australia's labour shortages and high costs. However, dry-stacked interlocking brick assemblies inherently exhibit gaps between bricks arising from surface roughness and dimensional variations. Extensive research has shown that these gaps induce stress concentrations and initial non-linear behaviour under static compressive and shear loading while enhancing energy absorption and dissipation under dynamic loading. Despite their known influence on dynamic performance parameters, the impacts of inter-brick gaps on the dynamic response of dry-stacked interlocking bricks during impact loading remain unknown. This study characterises the dynamic response through a combination of experimental testing, analytical simplifications, and stochastic analysis of interlocking brick assemblies. Instrumented impact hammer tests conducted on interlocking assemblies revealed that the inherent gaps cause pounding between adjacent bricks, resulting in high-frequency dynamic responses. An analytical approach was developed to characterise the inter-brick pounding, with results indicating that the timing of pounding events primarily influences the dominant frequency of the assembly. A stochastic method was employed to directly assess the influence of inter-brick gaps on the Fourier spectrum and to establish the boundaries of the analytical analysis. Furthermore, a novel design integrating meta-concrete with interlocking bricks is proposed to exploit these high-frequency responses beneficially. Numerical simulations demonstrated that meta-concrete interlocking brick systems attenuated acceleration responses induced by impact forces by up to 26 %, highlighting the synergy between these technologies for potential applications.
  • Thumbnail Image
    Item
    33
    (33, 33) Hernández, Francisco; Astroza, Rodrigo; Beltrán, Juan Felipe; Zhang, Xihong; Mercado, Vicente; 33
    An energy dissipation mechanism made of a cable-pulleys system placed in series with a spring-damper device (fluid viscous) is experimentally studied. The system aims to provide high damping ratios for all the structural modes by using a unique spring-damper device to dissipate the seismic energy of the entire structure (and all its structural modes). Shake table tests and pull-back tests are carried out on a scaled five-story structure to compare the dissipation capabilities provided by the proposed system. Therefore, the same structure is tested under different configurations that included: i) the structure itself without any energy mitigation device, ii) the structure with viscous dampers installed on each story, iii) the structure with the proposed cable-pulleys and the spring-damper system, and iv) the structure with the cable-pulleys system but without any dissipation device. The experimental results showed that the structure with the proposed system exhibits a highly nonlinear response (mainly explained by the cable-pulleys interaction) evidenced by the significant change of the structure's dynamic properties during the time. The Short-Time Transfer Function plots show that the structure's natural frequencies change significantly when the cable-pulleys system is included. Complementarily, a novel time-variant system identification approach, termed Mod-?(var), is proposed, which allows estimating the time-variant evolution of the structure's dynamic properties during seismic tests (natural frequencies, damping ratios, and mode shapes). Moreover, the Mod-?(var) approach also enables computing relevant engineering quantities such as the empirical response spectrum from experimental data. It is found that the analyzed energy dissipation system provides high damping ratios (>10%) for all the structural modes, allowing reducing the seismic demands in terms of the empirical response spectrum, inter-story drifts, inter-story shear forces, peak accelerations, and Housner Intensities at each floor.
  • Thumbnail Image
    Item
    Analysis of fuel storage tanks under internal deflagrations with different venting technologies: an experimental and numerical study
    Hernandez, Francisco; Carcamo, Luis; Hao, Hong; Zhang, Xihong; Contreras, Nicolas; Astroza, Rodrigo
  • Thumbnail Image
    Item
    Application of elastic metamaterials/meta-structures in civil engineering: a review
    Contreras, Nicolás; Zhang, Xihong; Hao, Hong; Hernández, Francisco
  • Thumbnail Image
    Item
    Time variant system identification of superstructures of base-isolated buildings
    Hernández, Francisco; Díaz, Pablo; Astroza, Rodrigo; Ochoa-Cornejo, Felipe; Zhang, Xihong