The concept of “structural fuse” for seismic energy dissipation has been widely adopted in both design standards and research worldwide. Among the metallic structural fuses, slit-yielding dampers, which dissipate energy through in-plane yielding of steel strips, have shown significant promise due to their high ductility and stable hysteretic behavior. However, their effectiveness can be compromised under bi-directional deformations, which may trigger lateral-torsional buckling. This study examines how geometric parameters influence the distribution and accumulation of plastic strains, the onset of buckling, and the energy dissipation capacity of dumbbell-shaped steel strip dampers. A refined non-linear finite element model (FEM) was developed, validated against experimental results, and used to perform non-linear buckling analyses considering initial geometric imperfections. A comprehensive parametric study was carried out on dumbbell-shaped steel strips with varying geometries to assess their susceptibility to yielding and lateral-torsional buckling. The findings highlight the importance of precise geometric control in the design of dumbbell-shaped steel strip dampers to ensure stable energy dissipation under cyclic loading. This is due to the high sensitivity of buckling-induced strength degradation to geometric parameters such as the length-to-thickness ratio, slenderness, aspect ratio, and initial imperfection amplitude. For example, at an aspect ratio of 5.5, an 8 % increase in slenderness resulted in a 39 % reduction in strength, while increasing the initial imperfection from L0/1000 to L0/500 led to a 30 % drop in peak strength for slenderness of 105.63. To address this, acceptance criteria based on buckling-induced resistance degradation were defined to determine a critical slenderness threshold. A regression analysis revealed a strong correlation between critical slenderness and initial imperfection, with regression coefficients linearly dependent on the aspect ratio. The model achieved coefficients of determination (R2) ranging from 0.9818 to 0.9969 under monotonic loading, and from 0.8980 to 0.9881 under cyclic loading. Based on this analysis, a practical design formula was developed to predict the critical slenderness of dumbbell-shaped steel strips under cyclic loading. Calibrated using the FEM dataset and validated across a range of imperfections and aspect ratios, the formula demonstrated strong accuracy, with standard deviation from 0.0145 to 0.0452, and standard error varying from 0.0065 to 0.0202.
Lateral torsional buckling design of dumbbell-shaped steel strip dampers
Ferraioli M.
;Mottola S.;De Matteis G.
2025
Abstract
The concept of “structural fuse” for seismic energy dissipation has been widely adopted in both design standards and research worldwide. Among the metallic structural fuses, slit-yielding dampers, which dissipate energy through in-plane yielding of steel strips, have shown significant promise due to their high ductility and stable hysteretic behavior. However, their effectiveness can be compromised under bi-directional deformations, which may trigger lateral-torsional buckling. This study examines how geometric parameters influence the distribution and accumulation of plastic strains, the onset of buckling, and the energy dissipation capacity of dumbbell-shaped steel strip dampers. A refined non-linear finite element model (FEM) was developed, validated against experimental results, and used to perform non-linear buckling analyses considering initial geometric imperfections. A comprehensive parametric study was carried out on dumbbell-shaped steel strips with varying geometries to assess their susceptibility to yielding and lateral-torsional buckling. The findings highlight the importance of precise geometric control in the design of dumbbell-shaped steel strip dampers to ensure stable energy dissipation under cyclic loading. This is due to the high sensitivity of buckling-induced strength degradation to geometric parameters such as the length-to-thickness ratio, slenderness, aspect ratio, and initial imperfection amplitude. For example, at an aspect ratio of 5.5, an 8 % increase in slenderness resulted in a 39 % reduction in strength, while increasing the initial imperfection from L0/1000 to L0/500 led to a 30 % drop in peak strength for slenderness of 105.63. To address this, acceptance criteria based on buckling-induced resistance degradation were defined to determine a critical slenderness threshold. A regression analysis revealed a strong correlation between critical slenderness and initial imperfection, with regression coefficients linearly dependent on the aspect ratio. The model achieved coefficients of determination (R2) ranging from 0.9818 to 0.9969 under monotonic loading, and from 0.8980 to 0.9881 under cyclic loading. Based on this analysis, a practical design formula was developed to predict the critical slenderness of dumbbell-shaped steel strips under cyclic loading. Calibrated using the FEM dataset and validated across a range of imperfections and aspect ratios, the formula demonstrated strong accuracy, with standard deviation from 0.0145 to 0.0452, and standard error varying from 0.0065 to 0.0202.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
