• Title/Summary/Keyword: metallic yielding devices

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Cyclic testing of a new visco-plastic damper subjected to harmonic and quasi-static loading

  • Modhej, Ahmad;Zahrai, Seyed Mehdi
    • Structural Engineering and Mechanics
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    • v.81 no.3
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    • pp.317-333
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    • 2022
  • Visco-Plastic Damper (VPD) as a passive energy dissipation device with dual behavior has been recently numerically studied. It consists of two bent steel plates and segments with a viscoelastic solid material in between, combining and improving characteristics of both displacement-dependent and velocity-dependent devices. In order to trust the performance of VPD, for the 1st time this paper experimentally investigates prototype damper behavior under a wide range of frequency and amplitude of dynamic loading. A high-axial damping rubber is innovatively proposed as the viscoelastic layer designed to withstand large axial strains and dissipate energy accordingly. Test results confirmed all assumptions about VPD. The behavior of VPD subjected to low levels of excitation is elastic while with increasing levels of excitation, a significant source of energy dissipation is provided through the yielding of the steel elements in addition to the viscoelastic energy dissipation. The results showed energy dissipation of 99.35 kN.m under a dynamic displacement with 14.095 mm amplitude and 0.333 Hz frequency. Lateral displacement at the middle of the device was created with an amplification factor obtained ranging from 2.108 to 3.242 in the rubber block. Therefore, the energy dissipation of viscoelastic material of VPD was calculated 18.6 times that of the ordinary viscoelastic damper.

Experimental study on a Cantilever Type Metallic Damper for Seismic Retrofit of Building Structures (건물의 내진보강을 위한 캔틸레버타입 강재댐퍼의 실험)

  • Ahn, Tae-Sang;Kim, Young-Ju;Park, Jin-Hwa;Kim, Hyung-Geun;Jang, Dong-Woon;Oh, Sang-Hoon
    • Journal of Korean Society of Steel Construction
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    • v.24 no.2
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    • pp.149-161
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    • 2012
  • The use of seismic energy-dissipative devices for passive control is increasing exponentially in the recent years for both new and existing buildings. Use of these devices started in and has been somewhat limited to developed countries. One of the current challenges is to promote the use of seismic dampers in earthquake-prone developing countries by lowering the cost of the devices. This paper proposed a new type of seismic damper based on yielding of a cantilever type metallic element for seismic retrofit of existing and new building structures. The hysteretic behavior and energy dissipation capacity of the proposed damper was investigated using component tests under cyclic loads. The experimental results indicated that the damping device had stable restoring force characteristics and a high energy dissipation capacity. Based on these results, a simple hysteretic model for predicting the load-displacement curve of the seismic damper was proposed.