Browsing by Author "Awoyera, Paul Oluwaseun"

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    Multi-Story Buildings Equipped with Innovative Structural Seismic Shear Fuse Systems
    Farzampour, Alireza; Mortazavi, Seyed Javad; Mansouri, Iman; Awoyera, Paul Oluwaseun; Wan Hu, Jong (Elsevier, 2022-03-29)
    Infrastructures could be designed and constructed to resist seismic lateral loads without experiencing a significant amount of damage concentrations in specific area. Having sufficient strength and stiffness to reduce the structural vulnerabilities against serious damages under seismic loading, requires structural elements to have adequate ductility and energy dissipating capability, which could be provided with the use structural dampers. These elements are typically replaceable, and designed to yield and protect the surrounding members from damages, and then be accessible after a major event. In this study, butterfly-shaped links with linearly varying width between larger ends and a smaller middle section are used for redesigning the prototype structures due to substantial ductility and stable energy dissipation capability. The effect of implementation of innovative seismic dampers in multi-story structures is investigated by analyzing multi-story prototype structures with structural seismic shear dampers, and subsequently compared with simple conventional linking beams. The results of the nonlinear response history analysis are summarized for 44 ground motions under maximum considered earthquake (MCE) and designed based earthquake (DBE) hazard levels. It is shown that implementation of the butterfly-shaped dampers in buildings with similar stiffness and strength leads to higher dissipated energy and less pinched curves compared to typical eccentrically braced frame systems. It is determined that the general stiffness and strength of the system with the butterfly-shaped link is close to conventional models; however, the demands on the surrounding boundary elements are lower than the corresponding conventional model, which could be beneficent for improving the seismic performance of the structural systems.
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    Optimization of the Curved Metal Damper to Improve Structural Energy Dissipation Capacity
    Kim, Young-Chan; Mortazavi, Seyed Javad; Farzampour, Alireza; Hu, Jong Wan; Mansouri, Iman; Awoyera, Paul Oluwaseun (MDPI, 2022-01-11)
    Structural curved metal dampers are implemented in various applications to mitigate the damages at a specific area efficiently. A stable and saturated hysteretic behavior for the in-plane direction is dependent on the shape of a curved-shaped damper. However, it has been experimentally shown that the hysteretic behavior in the conventional curved-shaped damper is unstable, mainly as a result of bi-directional deformations. Therefore, it is necessary to conduct shape optimization for curved dampers to enhance their hysteretic behavior and energy dissipation capability. In this study, the finite element (FE) model built in ABAQUS, is utilized to obtain optimal shape for the curved-shaped damper. The effectiveness of the model is checked by comparisons of the FE model and experimental results. The parameters for the optimization include the curved length and shape of the damper, and the improved approach is conducted by investigating the curved sections. In addition, the design parameters are represented by B-spline curves (to ensure enhanced system performance), regression analysis is implemented to derive optimization formulations considering energy dissipation, constitutive material model, and cumulative plastic strain. Results determine that the energy dissipation capacity of the curved steel damper could be improved by 32% using shape optimization techniques compared to the conventional dampers. Ultimately, the study proposes simple optimal shapes for further implementations in practical designs.
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    Optimization of the curved metal damper to improve structural energy dissipation capacity
    Kim, Young-Chan; Mortazavi, Seyed Javad; Farzampour, Alireza; Hu, Jong Wan; Mansouri, Iman; Awoyera, Paul Oluwaseun (MDPI, 2022-01-15)
    Structural curved metal dampers are implemented in various applications to mitigate the damages at a specific area efficiently. A stable and saturated hysteretic behavior for the in-plane direction is dependent on the shape of a curved-shaped damper. However, it has been experi-mentally shown that the hysteretic behavior in the conventional curved-shaped damper is un-stable, mainly as a result of bi-directional deformations. Therefore, it is necessary to conduct shape optimization for curved dampers to enhance their hysteretic behavior and energy dissipa-tion capability. In this study, the finite element (FE) model built in ABAQUS, is utilized to obtain optimal shape for the curved-shaped damper. The effectiveness of the model is checked by com-parisons of the FE model and experimental results. The parameters for the optimization include the curved length and shape of the damper, and the improved approach is conducted by investi-gating the curved sections. In addition, the design parameters are represented by B-spline curves (to ensure enhanced system performance), regression analysis is implemented to derive optimi-zation formulations considering energy dissipation, constitutive material model, and cumula-tive plastic strain. Results determine that the energy dissipation capacity of the curved steel damper could be improved by 32% using shape optimization techniques compared to the con-ventional dampers. Ultimately, the study proposes simple optimal shapes for further imple-mentations in practical designs.