Experimental and mathematical model of the variable friction adaptive self-centering energy dissipative brace

The self-centering energy dissipative (SCED) brace can limit the maximum story drift and eliminate residual drift during an earthquake. The inadequate reliability or excessive complexity of the energy dissipative system, the contradiction between the energy dissipative system and self-centering system, the limited elongation capacity, and the difficulty in replacement and reuse are the main challenges faced by the existing developed SCED brace. To solve these problems, a variable friction adaptive self-centering energy dissipative (VFA-SCED) brace has been proposed. First, the details of the VFA-SCED brace are introduced, and the force analysis of each component and the working mechanism of the brace are expounded. Then, the equations that govern the brace performance have been derived, key parameters and mathematical models have been identified. Finally, the feasibility of the new system was demonstrated with a set of experiments, in which five specimens with different key parameters were fabricated, tested, and analyzed. The test results show that the hysteretic curve of the VFA-SCED brace is typically flag-shaped, and there is almost no residual deformation after multiple cyclic loadings, which means that the brace has good energy dissipative capacity and self-centering ability, replaceable and recyclable for each component, and stable working performance. The elongation capacity, friction, energy dissipative capacity, and self-centering ability can be changed by adjusting the relevant key parameters of the spring and wedge block, and the proposed mathematical model can well predict the force-deformation hysteresis of the brace with different parameters. The results show that the VFA-SCED brace successfully avoids the main obstacles of previous SCED braces.