DESIGN PROCEDURES FOR SHOCK ISOLATION SYSTEMS OF UNDERGROUND PROTECTIVE STRUCTURES. VOLUME 3. RESPONSE SPECTRA OF SINGLE-DEGREE-OF-FREEDOM ELASTIC AND INELASTIC SYSTEMS

1964 ◽  
Author(s):  
A. S. Veletsos ◽  
N. M. Newmark
Keyword(s):  
Response Spectra ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Design Procedures ◽  
Single Degree ◽  
Shock Isolation ◽  
Isolation Systems ◽  
Protective Structures

Effects of human-induced load models on tuned mass damper in reducing floor vibration

2019 ◽  
Vol 22 (11) ◽  
pp. 2449-2463
Author(s):  
Jun Chen ◽  
Ziping Han ◽  
Ruotian Xu
Keyword(s):  
Response Spectra ◽  
Tuned Mass Damper ◽  
Design Guidelines ◽  
Degree Of Freedom ◽  
Dynamic Responses ◽  
Single Degree Of Freedom ◽  
Load Model ◽  
Load Models ◽  
Single Degree ◽  
Mass Damper

Dozens of human-induced load models for individual walking and jumping have been proposed in the past decades by researchers and are recommended in various design guidelines. These models differ from each other in terms of function orders, coefficients, and phase angles. When designing structures subjected to human-induced loads, in many cases, a load model is subjectively selected by the design engineer. The effects of different models on prediction of structural responses and efficiency of vibration control devices such as a tuned mass damper, however, are not clear. This article investigates the influence of human-induced load models on performance of tuned mass damper in reducing floor vibrations. Extensive numerical simulations were conducted on a single-degree-of-freedom system with one tuned mass damper, whose dynamic responses to six walking and four jumping load models were calculated and compared. The results show a maximum three times difference in the acceleration responses among all load models. Acceleration response spectra of the single-degree-of-freedom system with and without a tuned mass damper were also computed and the response reduction coefficients were determined accordingly. Comparison shows that the reduction coefficient curves have nearly the same tendency for different load models and a tuned mass damper with 5% mass ratio is able to achieve 50%–75% response reduction when the structure’s natural frequency is in multiples of the walking or jumping frequency. All the results indicate that a proper load model is crucial for structural response calculation and consequently the design of tuned mass damper device.

A Modular-Type Three-Axis Vibration Isolation System Using Negative Stiffness

2010 ◽  
Author(s):  
Md. Emdadul Hoque ◽  
Takeshi Mizuno ◽  
Yuji Ishino ◽  
Masaya Takasaki
Keyword(s):  
Vibration Isolation ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Negative Stiffness ◽  
Isolation System ◽  
Single Degree Of Freedom ◽  
Vibration Isolation System ◽  
Single Degree ◽  
In Series ◽  
Isolation Systems

A vibration isolation system is presented in this paper which is developed by the combination of multiple vibration isolation modules. Each module is fabricated by connecting a positive stiffness suspension in series with a negative stiffness suspension. Each vibration isolation module can be considered as a self-sufficient single-degree-of-freedom vibration isolation system. 3-DOF vibration isolation system can be developed by combining three modules. As the number of motions to be controlled and the number of actuators are equal, there is no redundancy in actuators in such vibration isolation systems. Experimental results are presented to verify the proposed concept of the development of MDOF vibration isolation system using vibration isolation modules.

Vibration of Satellite Subsystem During Orbiter Lift-Off

1993 ◽  
Vol 8 (3) ◽  
pp. 167-176 ◽  
Author(s):  
Gina Lee-Glauser ◽  
Goodarz Ahmadi
Keyword(s):  
Response Spectra ◽  
Degree Of Freedom ◽  
Mass Ratio ◽  
Acceleration Response ◽  
Single Degree Of Freedom ◽  
Lump Parameter Model ◽  
Single Degree ◽  
Acceleration Response Spectra ◽  
Lift Off ◽  
Sinusoidal Excitation

Vibrations of a satellite and one of its sensitive subsystems during orbiter lift-off are studied. A single degree-of-freedom representation of the subsystem and a five degree-of-freedom lump parameter model of the satellite are considered. Deflection and acceleration response spectra of the satellite and its subsystem subject to sinusoidal excitation and the STS - 41 lift-off accelerations are evaluated. The significance of the subsystem and primary satellite interaction is investigated. The effect of mass ratio and damping coeficient of the subsystem on the peak deflection and acceleration response spectra of the satellite and its subsystem are examined.

scholarly journals On the Optimal Shock Isolation of a System with One and a Half Degrees of Freedom

1999 ◽  
Vol 6 (4) ◽  
pp. 159-167
Author(s):  
D.V. Balandin ◽  
N.N. Bolotnik ◽  
W.D. Pilkey
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Numerical Examples ◽  
Single Degree ◽  
Shock Isolation

The limiting performance of shock isolation of a system with one and a half degrees of freedom is studied. The possibility of using a single-degree-of-freedom model for this analysis is investigated. The error of such an approximation is estimated. Numerical examples are presented.

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