Computational and experimental study of structural fuses optimized to resist buckling

Abstract

The concept of structural fuses, i.e., replaceable hysteretic dampers that limit the forces that can be transferred to the surrounding structure, has been used in research and practice to improve the seismic performance of structural systems. A recent study used topology optimization to develop new structural fuse shapes that discourage buckling and promote stable yielding of shear-acting structural fuses. The objective of the current study is to further validate and develop the optimized shapes to allow the design and application of these optimized structural fuse shapes in practice. First, the pixelated optimized topology was interpreted as a collection of geometric shapes, parameterized to make it accessible for design, and plastic mechanism analysis was used to develop a generalized equation for shear strength. An experimental study was conducted on three specimens that were 711 mm by 762 mm by 25 mm thick, to evaluate strength, stiffness and hysteretic behavior. Finite element models were then validated against the experimental results, and used to conduct a computational parametric study to evaluate the effect of varying key design parameters on strength, stiffness, out-of-plane buckling, effective plastic strain, and energy dissipation. The experimental study showed that one of the optimized geometries possessed a good balance between buckling resistance and fracture resistance reaching approximately 11% shear angle without either. Design guidance is provided for this topology including a parameterized method for reproducing the shape, design equations, and recommendations for proportioning.