• Earthquakes and Structures
• /
• v.18 no.5
• /
• pp.637-648
• /
• 2020

In this study, a new steel cylindrical shell configuration of the dissipative energy device is proposed to improve lateral ductility and to reduce the damage of the structures against seismic forces. Four nested-eccentric- cylindrical shells are used to constructing this device; therefore, this proposed device is named nested-eccentric-cylindrical shells damper (NECSD). The particular configuration of the nested-eccentric-cylindrical shells is applied to promote the mechanical characteristics, stability, and overall performance of the damper in cyclic loads. Shell-type components are performed as a combination of series and parallel non-linear springs into the in-plan plastic deformation. Numerical analysis with respect to dimensional variables are used to calculate the mechanical characteristics of the NECSD, and full-scale testing is conducted for verifying the numerical results. The parametric study shows the NECSD with thin shells were more flexible, while devices with thick shells were more capacious. The results from numerical and experimental studies indicate that the NECSD has a stable behavior in hysteretic loops with highly ductile performance, and can provide appropriate dissipated energy under cyclic loads.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2001.09a
• /
• pp.381-388
• /
• 2001

Behavior characteristics of coil shaped elastoplastic dampers, a sort of hysteretic damper, are studied on through experiments and numerical analyses. The coil shaped elastoplastic damper shows bilinear force-deformation relationship, and no stress concentration is occurred in the device. Numerical model, which is constructed through calibration with experimental results, shows good agreement with experiment, The coil shaped elastoplastic damper has lower yielding strength and stiffness under transversal loading compared to axial leading. Additional studies are required on behavior characteristics according to configuration variation of coil shaped elastoplastic dampers.

• Journal of Korean Association for Spatial Structures
• /
• v.17 no.4
• /
• pp.35-42
• /
• 2017

This study develops a new hybrid passive energy dissipation device for seismic rehabilitation of an existing structure. The device is composed of a friction damper combined with a steel plate with vertical slits as a hysteretic damper. Analytical model is developed for the device, and the capacity of the hybrid device to satisfy a given target performance is determined based on the ASCE/SEI 7-10 process. The effect of the device is verified by nonlinear dynamic analyses using seven earthquake records. The analysis results show that the dissipated inelastic energy is concentrated on the hybrid damper and the maximum interstory drift of the SMRF with damping system satisfies the requirement of the current code.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.6
• /
• pp.10-17
• /
• 2015

In this study, to examine seismic reinforcement effect of a school building constructed prior to application of seismic design, a Double I-type damper supported by wall was installed to perform comparative analysis on existing non-seismic designed RC frame. As a result of experiment, while non-seismic designed specimen showed rapid reduction in strength and brittle shear destruction as damages were focused on top and bottom of left and right columns, reinforced specimen showed hysteretic characteristics of a large ellipse with great energy absorption ability, exhibiting perfectly behavior with increased strength and stiffness from damper reinforcement. In addition, as a result of comparing stiffness reduction between the two specimens, specimen reinforced by shear wall type damper was effective in preventing stiffness reduction. Energy dissipation ability of specimen reinforced by Double I-type damper was about 3.5 times as high as energy dissipation ability of non-reinforced specimen. Such enhancement in energy dissipation ability is considered to be the result of improved strength and deformation.

• Journal of Mechanical Science and Technology
• /
• v.18 no.11
• /
• pp.1883-1890
• /
• 2004

It is important to have a precise model for the clutch damper in order to simulate the entire powertrain of a vehicle and predict the responses of the system. In this research, we developed a new model in which the spring used in the clutch damper is divided into a finite number of elements. The model takes many unique properties of arc-shaped springs into consideration and is anticipated to be more precise than conventional simple models. With the model, two meaningful results were presented which can be utilized afterwards. One is a simulation concerning the peak torque transmitted via the clutch damper. The other is a simulation that shows the hysteretic characteristics of the clutch damper.

• Journal of Korean Association for Spatial Structures
• /
• v.21 no.3
• /
• pp.61-68
• /
• 2021

In this study, a rocking behavior experiment using a guide plate and a guide channel to prevent lateral deformation of a steel damper was planned. For this purpose, strut I-type specimen I-1 and strut S-type specimen S-1 were prepared. The experimental results were compared with the existing experimental results of SI-260 and SS-260 under the same conditions without the details of lateral deformation prevention in order to evaluate the effect of preventing lateral deformation. The damper with lateral deformation prevention detail was evaluated to have superior strength capacity, deformation capacity, and energy dissipation capacity than the damper without it. Therefore, the lateral deformation prevention detail was evaluated to have a good effect in improving the design capability of the steel damper.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.5
• /
• pp.199-208
• /
• 2011

The purpose of this study is to evaluate of the strength and deformation capacity of metallic dampers with the variable slit shape. For this purpose, 12 metallic damper specimens were prepared and shear testing was performed. According to the test results, the S shaped metallic damper with the strut height of 200mm and angle of $60^{\circ}$ shows better hysteretic performance than any other specimens. By making a comparison between the yield strength in test and the proposed strength formula, test results shows larger yield strength than calculation method.

• Structural Engineering and Mechanics
• /
• v.30 no.6
• /
• pp.787-790
• /
• 2008

• Journal of Korean Association for Spatial Structures
• /
• v.16 no.3
• /
• pp.99-106
• /
• 2016

The proposed hybrid damper installs at a coupling beam and consists of a high-damping rubber (HDR) and steel pin. The proposed hybrid damper adopted a pin-lock system acts as a viscoelastic damper under wind load (small displacement) while it behaves as a hysteretic damper under earthquake load (large displacement). In this paper, the pin-lock mechanism and structural performance of the proposed hybrid damper is evaluated through experiment. Experiments were carried out with the variables which displacement, loading frequency and steel pin quantities were used. Test results showed that the pin-lock mechanism and the performance of the hybrid damper under a large displacement were verified. Also equivalent damping ratios of HDR were increasing at a small displacement as displacement amplitudes were increasing. However HDR did not depend on frequency.

• Earthquakes and Structures
• /
• v.23 no.4
• /
• pp.363-371
• /
• 2022

Traditional metal dampers have disadvantages such as a higher yield point and inadequate adjustability. The experimental results show that the low yield point steel has superior energy dissipation hysteretic capacity and can be applied to seismic structures. To overcome these deficiencies, a novel compound metal damper comprising both low yield point steel plates and common steel plates is presented. The optimization objectives, including "maximum rigidity" and "full stress state", are proposed to obtain the optimal edge shape of a compound metal damper. The numerical results show that the optimized composite metal damper has the advantages such as full hysteresis curve, uniform stress distribution, more sufficient energy consumption, and it can adjust the yield strength of the damper according to the engineering requirements. In view of the mechanical characteristics of the compound metal damper, the equivalent model of eccentric cross bracing is established, and the approximate analytical solution of the yield strength and the yield displacement is proposed. A nonlinear simulation analysis is carried out for the overall aseismic capacity of three-layer-frame structures with a compound metal damper. It is verified that a compound metal damper has better energy dissipation capacity and superior seismic performance, especially for a damper with double-objective optimized shape.