Cast steel seismic energy dissipation devices are designed so that during an earthquake, inelastic demands are concentrated in specially designed distributed yielding sections within the devices, thus ensuring a primarily elastic response elsewhere in the structure. The yielding sections of such devices are designed to preclude local buckling and exhibit a stable hysteretic response with a large energy dissipation capability. Typically, the ultimate limit state of these components is ultra-low-cyclic fatigue (ULCF) fracture of the yielding sections, where fracture begins after relatively low number of large displacement cycles.
The Yielding Connector (YC) is one variety of such devices, and is designed for use in highly ductile concentric brace frame systems, or as a damper in other configurations. The YC’s yielding sections consist of a series of triangular yielding fingers. This paper presents the calibration of the cyclic void growth model (CVGM), an ULCF fracture model, to the cast steel material in the YC by performing a series of monotonic and cyclic notched coupon tests. Advanced finite element numerical models of a full-scale experimental test were used to validate the calibrated CVGM fracture prediction with the experimental results. Use of the calibrated CVGM is then presented as a design tool in the context of the prototype design of a cast steel replaceable link for eccentrically braced frames.
