Adaptive base-isolation of civil structures using variable amplification

Walsh, Kenneth K.; Abdullah, Makola M.

doi:10.1007/s11803-006-0643-9

Cited by 5 publications

(4 citation statements)

References 30 publications

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“…The expression in Equation (22) provides the exact value of the scissor-jack damper amplification factor for any value of the frame displacements u(t) and v(t). However, the equation is dependent on the geometry of the scissor-jack damper system at time t and requires calculating the angle ψ(t) at each time step during dynamic analysis.…”

Section: Scissor-jack-damper Displacement Amplificationmentioning

confidence: 99%

“…Although the general form of the amplification factor in Equation (12) is convenient for expressing the amplification factors in Equations (14), (22), and (26), its numerical implementation can result in singularities for u(t) = 0. Such singularities will result in an undefined value for the control force F c (t) calculated from Equation (10) and subsequent early termination of the simulation.…”

Section: Numerical Implementationmentioning

confidence: 99%

“…Then, the true amplification factor of the system was calculated as f CAD = u D /u. These factors are presented in column 3 of Table I along with the corresponding amplification factors calculated using Equations (14), (15), (22), and (26). In addition, the percent errors between these values and the true amplification factors f CAD are also included.…”

Section: Scissor-jack Damper Model Validationmentioning

confidence: 99%

“…More recently, the displacement amplification device was developed . A similar device was proposed for semi‐active control by using variable amplification . In each case, rack and pinion mechanisms are used to connect the system between the structure and the damper .…”

Section: Introductionmentioning

confidence: 99%

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Dynamic analysis of seismically excited flexible truss tower with scissor-jack dampers

Walsh

Cronin

Rambo-Roddenberry

et al. 2011

Struct. Control Health Monit.

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SUMMARY In the proposed work, numerical simulations are conducted to investigate scissor‐jack dampers for controlling vibrations in a seismically excited flexible truss tower. For the scissor‐jack damper, new equations are developed to model the amplification factor that account for large deformations of the damper assembly. The equations are validated using computer‐aided design and are used to investigate the influence of vertical deformations on scissor‐jack damper amplification. Then, seismic analysis is carried out for scissor‐jack dampers installed on a 3D flexible truss tower. To reduce the computational effort, a bi‐model method is employed to represent the 3D truss tower as a dynamically equivalent 2D model. To describe the interaction between the structure and scissor‐jack dampers, the displacement‐dependent amplification factors of the scissor‐jack devices and the corresponding damper forces are calculated at each time step. The response of the tower with scissor‐jack damper systems is simulated for a range of damping and four major earthquakes and time histories of the displacement and absolute acceleration at each level of the tower are obtained. Results indicate that the system is effective in reducing both the displacement and absolute acceleration response of the tower without exceeding damper stroke capacity in most cases, but that damping level and earthquake intensity are important factors in the consideration of scissor‐jack dampers for flexible structures subject to seismic loads. Copyright © 2011 John Wiley & Sons, Ltd.

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Section: Scissor-jack-damper Displacement Amplificationmentioning

confidence: 99%

Section: Numerical Implementationmentioning

confidence: 99%