<p>This study investigates the performance optimization of LY160 low-yield-point steel prefabricated fan-shaped metallic dampers (PFMDs). A novel fan-shaped energy-dissipating damper with a cross-shaped perforation design is proposed, and the impact of different open-area ratios on its load-bearing capacity and energy dissipation is thoroughly examined. Three sets of PFMD specimens, with open-area ratios of 5%, 10%, and 15%, were designed and subjected to quasi-static cyclic loading tests. Comprehensive finite element analyses were performed to explore how the open-area ratio affects the evolution of plastic zones, stress redistribution, and hysteretic behavior. The results show that a moderate increase in the open-area ratio helps form continuous energy-dissipating bands along the diagonal of the plastic zones. This improves the stress distribution, leading to fuller hysteresis loops and significantly better energy dissipation efficiency. The peak load of the dampers follows a non-monotonic trend with the open-area ratio, initially rising and then falling. The 10% open-area ratio specimens exhibited the best overall performance. At large rotation angles (0.04&#xa0;rad), the equivalent viscous damping coefficient reached 0.27, approximately 17% higher than that of the 5% open-area ratio specimens. Numerical simulations closely match experimental results, confirming the reliability of the perforation control mechanism. This study provides a systematic explanation of the coupled relationship between open-area ratio, plastic zone distribution, energy dissipation, and load-bearing capacity, offering new insights into the behavior of low-yield-point steel fan-shaped perforated dampers. The findings offer a foundation for the parametric design of replaceable metallic dampers in prefabricated structures, ensuring a balance between load-bearing capacity and energy dissipation performance.</p>