A Comparative Seismic Performance Assessment of Metallic Dissipaters Made of Mild Steel, Aluminum, and Titanium Alloys

Metallic dissipaters, which are displacement-activated devices, can be used to absorb seismic energy during an earthquake by yielding under axial, flexural, torsional, or shear deformation. They offer advantages such as simple fabrication, cost-effectiveness, the use of off-the-shelf parts such as metal plates, options for bolting or welding in connection, postearthquake replaceability, and flexibility for installation in structures made of concrete, steel, timber, and composites. Over the years, many types of metallic dissipaters have been proposed and tested. This study focuses on investigating three types of metallic dissipaters, namely, the U-shaped flexural plate (UFP), grooved dissipater (GD), and torsional beam dissipater (TBD). In addition, a modified version of UFP, referred to as M-UFP, has been investigated. While mild steel has traditionally been the material of choice for dissipater fabrication, its application is limited by its susceptibility to corrosion and the requirement for larger sizes to achieve sufficient energy dissipation, which creates challenges in terms of space and aesthetics. Therefore, in this study, aluminum and titanium alloys are proposed as alternative materials. The seismic performance of UFPs, GDs, and TBDs made of the three different alloys (mild steel, aluminum, and titanium) is experimentally investigated. The experimental results demonstrated that the dissipaters made of titanium alloy had the least residual deformation, which is 47% less than mild steel and 32% less than aluminum in UFPs. In comparison, this value is 54% and 57% less than mild steel and aluminum in GDs and 52% and 44% less than mild steel and aluminum in TBDs, respectively. Titanium dissipaters also showed the highest strength compared to the dissipaters made of aluminum and mild steel. Furthermore, M-UFP made of mild steel has been proposed with two design configurations, namely, with and without a reinforcing pipe around the bending curvature. Reinforced M-UFP showed improved seismic performance and stable hysteresis response compared to unreinforced M-UFP.