Research on Design Methodology and Finite Element Analysis of Inner Cores for Multi-Level Energy Dissipation and Self-Centering BRBs—Part II: Self-Centering Circular Frustum Device

This paper introduces an innovative inner core for buckling-restrained braces, referred to as the Aluminum-Engineered Cementitious Composite-Circular Frustum Composite (ALECCYT) inner core, which incorporates multi-stage energy dissipation mechanisms and self-centering capabilities. The initial stiffness calculation formula for the self-centering circular frustum (YT) device is derived theoretically, and a sizing design methodology for its critical components is proposed, specifically tailored to achieve a preset failure mode. Based on this, seven YT device specimens with varying tonnages, both conforming and non-conforming to the design methodology, were designed and analyzed through finite element simulations. The results demonstrate that the hysteretic curve of the appropriately designed YT device exhibits a flag-like shape, with minimal residual displacement after unloading, effective hysteretic energy dissipation, and robust self-centering capabilities, while adhering to the intended failure mode. Conversely, specimens that fail to meet the buckling constraints may encounter failures such as Shape Memory Alloy (SMA) buckling, steel ring buckling, and Carbon Fiber Reinforced Polymer (CFRP) ring buckling during loading, leading to the inefficient utilization of material strengths. The findings from the finite element analyses provide preliminary validation of the effectiveness of the proposed design methodology.