Adjustable template stiffness device and SDOF nonlinear frequency response

Lai, Zhilu; Sun, Tiecheng; Nagarajaiah, Satish

doi:10.1007/s11071-019-04871-4

Cited by 26 publications

(8 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To further validate the proposed framework via use of experimental data, we employ the proposed scheme to learn the governing dynamics of a structure equipped with a negative stiffness device (NSD) [52][53][54][55][56][57] serving for vibration mitigation, which results in a highly nonlinear dynamical system. As shown in Figure 10, the structure is a three-story frame that has been tested on a single-axis shake table.…”

Section: Experimental Examples 41 a Structural System Equipped With A Negative Stiffness Devicementioning

confidence: 99%

Structural identification with physics-informed neural ordinary differential equations

Lai

Mylonas

Nagarajaiah

et al. 2021

Journal of Sound and Vibration

Self Cite

117

View full text Add to dashboard Cite

Section: Experimental Examples 41 a Structural System Equipped With A Negative Stiffness Devicementioning

confidence: 99%

Structural identification with physics-informed neural ordinary differential equations

Lai

Mylonas

Nagarajaiah

et al. 2021

Journal of Sound and Vibration

Self Cite

117

View full text Add to dashboard Cite

“…In essence, the NSD with the damper is able to reduce the frequency response function of the composite system significantly. The full details of the analytical and experimental evaluation under harmonic excitation (nonlinear frequency response function), evaluation of the backbone curves, of a more versatile form of the proposed adaptive stiffness device—that can produce softening or stiffening or a combination, including positive hardening tangential stiffness (like a Duffing oscillator) and softening tangential stiffness (as in buckling) or a combination thereof—have been developed and are presented in a separate study . Nagarajaiah first proposed the idea of using a compressed spring rolling over a curved block for varying stiffness in a smart tuned mass damper.…”

Section: Verification Using Shaking Table Testmentioning

confidence: 99%

Negative stiffness device for seismic protection of smart base isolated benchmark building

Sun

Lai

Nagarajaiah

et al. 2017

Struct Control Health Monit

Self Cite

View full text Add to dashboard Cite

Summary This paper presents a novel negative stiffness device (NSD) for the seismic protection of the base isolated benchmark building in near fault earthquake. The benchmark structure has eight stories and irregular plan, and the superstructure is considered to be a linear elastic system with lateral torsional behavior. Furthermore, it is equipped with low damping elastomeric rubber bearings and viscous dampers for seismic protection. The proposed NSD can change the stiffness of composite structure‐device assembly, emulate “apparent yielding” of the structure system without permanent deformations. It consists of a highly compressed spring, a wheel and a curved template that the wheel can roll on. The device can achieve any force‐displacement behavior within its designed range. Experimental results are presented to verify the analytical model of the NSD. Numerical simulation results under seven earthquake inputs show that the proposed device is effective in reducing the response of the base and superstructure in comparison with a sample clipped optimal controller and an H2/LQG sample controller.

show abstract

“…Furthermore, parallel application of negative stiffness springs can upgrade the viscous damper to a negative stiffness amplified damper with higher damping effect. [21][22][23][24] The negative stiffness characteristics and damping amplification effect of negative stiffness damped outrigger in high-rise buildings significantly reduced the seismic response of the structure. Similarly, the application of negative stiffness and inertial mechanisms combined with viscous dampers has also been applied to multimodal cable vibration control.…”

Section: Introductionmentioning

confidence: 99%

“…18 Adjustable template stiffness device (ATSD) has also been proposed as a nonlinear add-on stiffness-modification device for structural vibration mitigation. 19 Sun and Nagarajaiah further proposed a novel adaptive passive stiffness (APS) device which can produce variable stiffness in an adaptive fashion. 20 This concept provides more possibilities for controlling structural vibrations in a passively adaptive manner.…”

Section: Introductionmentioning

confidence: 99%

A theoretical vibration‐reduction effect analysis of the floating slab track supported by nonlinear variable stiffness isolators and semi‐active magneto‐rheological dampers

Zhao

Wei

Cheng

et al. 2021

Structural Contr & Hlth

View full text Add to dashboard Cite

Nonlinear vibration control theory has resolved some bottleneck problems that cannot be solved by traditional linear vibration control theories. In this study, intelligent controllable magneto-rheological dampers (MR-Ds) and highstatic-low-dynamic variable stiffness vibration isolators (VS-VIs) are innovatively applied to a traditional steel-spring floating slab track (FST) to improve its low-frequency vibration-reduction effect. To determine the reasonable parameter group of the VS-VI and the parameter matching when used with MR-D, parameter groups were first preliminarily proposed through static and dynamic analyses of the equivalent single-degree-of-freedom (SDOF) model of the FST. A vertical vehicle-variable stiffness-magneto-rheological FST coupled dynamic model was established, and the parameter group was optimized based on safety and vibration-reduction analyses. The simulated results showed that the positive and negative stiffnesses were the key parameters that determined the stiffness nonlinearity level and dynamic support capacity of the VS-VI.Improving the positive stiffness is necessary to achieve a low-dynamic stiffness under no vehicle load and to ensure the millimeter-level dynamic displacement of the FST under vehicle load. An appropriate stiffness nonlinearity level can achieve a better vibration-reduction effect, and excessive nonlinearity level will not bring more significant improvements. The damping ratio in the dynamic analysis is a key parameter to prevent the jumping phenomenon, and the recommended value should not be less than 5%. Moreover, when the VS-VI and the MR-D were efficiently incorporated, a smaller MR damping force and larger displacement threshold could not only achieve a better vibrationreduction effect but also reduce the energy consumption.

show abstract

Adjustable template stiffness device and SDOF nonlinear frequency response

Cited by 26 publications

References 30 publications

Structural identification with physics-informed neural ordinary differential equations

Structural identification with physics-informed neural ordinary differential equations

Negative stiffness device for seismic protection of smart base isolated benchmark building

A theoretical vibration‐reduction effect analysis of the floating slab track supported by nonlinear variable stiffness isolators and semi‐active magneto‐rheological dampers

Contact Info

Product

Resources

About