Seismic performance of prefabricated stainless steel-composite material non-buckling restrained braces

This study proposes a novel prefabricated non-buckling restrained brace It consisted of a stainless steel inner core, glass fiber-reinforced polymer (GFRP) profile outer constraints, and polyamide unbonded filling layer. Through theoretical analysis, formulas for the equivalent axial stiffness and overall elastic buckling load of the brace were derived, and stability design criteria for the connection segments were established. Low-cycle repeated loading tests demonstrated that the brace maintains a stable non-buckling working state under compression, exhibiting full hysteresis curves, and possesses stable load-bearing performance. The stainless steel inner core exhibits distinct early yielding characteristics, enabling effective energy dissipation at lower axial strain levels. With its equivalent viscous damping ratio reaching a notable magnitude at relatively small strain amplitudes. This novel energy-dissipating brace features lightweight construction, corrosion resistance, ease of fabrication, and maintenance-free operation, showing promising applications in high-performance structures.