PSI - Issue 78

Yangwen Zhang et al. / Procedia Structural Integrity 78 (2026) 1008–1015

1009

Among such devices, the Maurer SHARK ® Hysteretic Damper stands out as an advanced, precisely engineered, and cost-e ff ective solution, as introduced in Huber and Weber (2023); Gandelli et al. (2021). It is composed of spe cially shaped lamellas arranged in both series and parallel configurations, forming the dissipative core, the key com ponent responsible for absorbing and dissipating seismic energy. The SHARK ® damper is available in two main configurations: one with a single dissipative core and another with a double dissipative core, as illustrated in Fig.1 (MAURER (2022)). This modular design allows for flexible application in various structural systems and performance requirements. The lamellas themselves are inspired by the gills of a shark, which is reflected in the product’s name. This distinctive geometry enables reliable sti ff ness, e ffi cient energy dissipation, and the capacity to endure a large number of deformation cycles before failure.

Fig. 1. SHARK ® Hysteretic Damper: (a) single core; (b) double core (adaptive).

Since hysteretic dampers dissipate energy through plastic deformation, making their low-cycle fatigue (LCF) per formance a critical concern (Usami et al. (2011); Fang et al. (2021); Zhou et al. (2025)). This is particularly critical in earthquake-prone regions, where a major seismic event is often followed by several strong aftershocks. For example, during the 2015 Nepal earthquake, the Gorkha region experienced seven aftershocks with magnitudes greater than 5.3 (Chen et al. (2017)). In such scenarios, dampers may face repeated seismic excitations without time for repair or replacement. Therefore, metallic hysteretic dampers must exhibit excellent and reliable LCF performance to ensure structural safety throughout their service life. Several seismic design codes specify requirements for the low-cycle fatigue performance of metallic hysteretic dampers. The American Institute of Steel Construction (AISC) stipulates that buckling-restrained braces (BRBs) must be capable of sustaining cumulative inelastic axial deformations equal to at least 200 times their yield deformation (AISC (2010)). In the Chinese seismic design code (JGJ (2013)), an index known as the Equivalent Hysteretic Cycles (EHCs) is used to evaluate the low-cycle fatigue performance of metallic dampers. This index must not be less than 30 cycles. The European code for seismic protection devices EN 15129 demands indirectly a low-cycle fatigue resistance of a magnitude greater than the applied load cycles in the factory production control which are in total 20 cycles including 10 cycles with the design displacement d bd . This paper presents a comprehensive study on the low-cycle fatigue performance of a double core Maurer SHARK ® Hysteretic Damper. A strain-based low-cycle fatigue life assessment is carried out using FEM simulation results obtained from Ansys. In addition, a prototype specimen is tested under quasi-static cyclic loading at an independent, certified testing facility. The experimental results are used to further evaluate the energy dissipation behaviour of the damper under repeated loading and assess the impact of low-cycle fatigue-induced cracking on its performance, providing valuable insights into the damper’s durability and seismic resilience.

2. Low-cycle fatigue analysis based on FEM

2.1. Strain life curve

The total strain amplitude ε a consists of both elastic and plastic components. Previous studies have shown that the relationship between plastic strain amplitude and fatigue life for steel forms an approximately linear trend when plotted on a log-log scale. This observation is commonly known as the Co ffi n-Manson relationship (Co ffi n (1954);