A Method for Extracting Building Empirical Capacity Curves from Earthquake Response Data

2016 ◽  
Vol 32 (4) ◽  
pp. 2229-2244 ◽  
Author(s):  
Jeffrey Dowgala ◽  
Ayhan Irfanoglu
Keyword(s):  
Small Scale ◽  
Earthquake Response ◽  
Viscous Damping ◽  
Acceleration Response ◽  
Damping Force ◽  
Restoring Force ◽  
Equivalent Viscous Damping ◽  
Strong Base ◽  
Capacity Curves ◽  
Response Data

A method is presented for extracting empirical capacity curves from building earthquake response data. The method can be applied to buildings with acceleration response records from each floor to develop story empirical capacity curves assuming the building has flexible columns and rigid floors. The method can also be applied to buildings with acceleration response records from the roof and ground to develop a fundamental mode empirical capacity curve. The method relies on extracting the restoring force and relative displacement of the system by removing damping force, considered as equivalent viscous damping, from the inertial response, using a proposed viscous damping identification procedure. The method is demonstrated using data from a small-scale, three-story experimental model subjected to strong base motion.

An Advanced Test Method to Determine Viscous Damping of Floating Structures

2010 ◽  
Author(s):  
Z. J. Huang ◽  
B. J. O’Donnell ◽  
T. W. Yung ◽  
S. T. Slocum
Keyword(s):  
Low Frequency ◽  
Test Method ◽  
Total Force ◽  
Viscous Damping ◽  
Damping Force ◽  
Restoring Force ◽  
Viscous Forces ◽  
Motion Time ◽  
Research Company ◽  
Time Histories

ExxonMobil Upstream Research Company developed an advanced model test method to determine reliable damping values for predicting low frequency motions of an FLNG barge and an LNG carrier. Since viscous damping forces are a very small portion of the total force on the model, how to separate the viscous forces from the total forces is the key technical challenge. To better isolate viscous damping forces, an inertial compensation system consisting of springs was employed in the test. The spring stiffness was designed such that the restoring force cancelled the large inertial loads at the oscillation frequency. Furthermore, double-body models were built and were deeply submerged to minimize surface wave damping. With such an experimental setup, the total force measured was mainly the viscous damping force. Viscous damping was derived from the measured force and motion time histories.

Study on the Effect of Modified Differential Restoring Force Model on Seismic Response of Isolation Structure

2014 ◽  
Vol 501-504 ◽  
pp. 1619-1622
Author(s):  
Jian Min Jin ◽  
Ping Tan ◽  
Xiang Yun Huang ◽  
Yan Hui Liu
Keyword(s):  
Numerical Analysis ◽  
Seismic Response ◽  
Significant Error ◽  
Earthquake Response ◽  
Force Model ◽  
Acceleration Response ◽  
Shear Tests ◽  
Comparison Result ◽  
Restoring Force ◽  
Restoring Force Model

Based on the compression-shear tests of different specifications LRBs (diameter 700mm,1000mm,1100mm) and shear strain correlation formula, the modified differential restoring force model (modified Bouc-Wen model) is suggested to simulate LRB. An isolated model, nine-story superstructure, is used as the numerical example. Using the unmodified and the modified differential restoring force model of the LRB, the differences of the seismic response of isolated structure are studied by numerical analysis and comparison. Result shows that, unmodified differential restoring force model commonly used in isolation design, except for acceleration response, other earthquake response has not significant error.

Actively Controlled Bearing Dampers for Aircraft Engine Applications

2000 ◽  
Vol 122 (3) ◽  
pp. 466-472 ◽  
Author(s):  
John M. Vance ◽  
Daniel Ying ◽  
Jorgen L. Nikolajsen
Keyword(s):  
Aircraft Engine ◽  
Companion Paper ◽  
Viscous Damping ◽  
Aircraft Engines ◽  
Damping Force ◽  
Equivalent Viscous Damping ◽  
Experimental Development ◽  
Critical Speeds ◽  
Coulomb Type ◽  
Er Damper

This paper describes some of the requirements for bearing dampers to be used in an aircraft engine and briefly discusses the pros and cons of various types of dampers that were considered as candidates for active control in aircraft engines. A disk type of electrorheological (ER) damper was chosen for further study and testing. The paper explains how and why the choice was made. For evaluating potential applications to aircraft engines, an experimental development engine (XTE-45) was used as an example for this study. Like most real aircraft engines, the XTE-45 ran through more than one critical speed in its operating speed range. There are some speeds where damping is desirable and other speeds where it is not. Thus, the concept of a damper with controllable forces appears attractive. The desired equivalent viscous damping at the critical speeds along with the available size envelope were two of the major criteria used for comparing the dampers. Most previous investigators have considered the ER damper to produce a purely Coulomb type of damping force and this was the assumption used by the present authors in this study. It is shown in a companion paper, however, that a purely Coulomb type of friction cannot restrain the peak vibration amplitudes at rotordynamic critical speeds and that the equivalent viscous damping for rotordynamics is different from the value derived by previous investigators for planar vibration. The type of control scheme required and its effectiveness was another criterion used for comparing the dampers in this paper. [S0742-4795(00)00803-6]

Vibration Isolation With Nonlinear Damping

1971 ◽  
Vol 93 (2) ◽  
pp. 627-635 ◽  
Author(s):  
Jerome E. Ruzicka ◽  
Thomas F. Derby
Keyword(s):  
Relative Velocity ◽  
Vibration Isolation ◽  
Damping Ratio ◽  
Nonlinear Damping ◽  
System Response ◽  
Viscous Damping ◽  
Damping Force ◽  
Isolation System ◽  
Equivalent Viscous Damping ◽  
Arbitrary Power

This paper discusses the performance characteristics of single degree-of-freedom vibration isolation systems in which the isolator damping force is proportional to the relative velocity across the isolator raised to an arbitrary power. The concept of equivalent viscous damping is employed to develop a general equation for the equivalent viscous damping ratio which is used to determine approximate isolation system response parameters. A range of isolator damping nonlinearity is studied by varying the relative velocity exponent between 0.5 and 5 for a fixed value of damping. Detailed results for parametric variations in damping are presented for specific values of the relative velocity exponent that correspond to Coulomb, viscous, quadratic, and cubic damping mechanisms.

Supplemental Damping for Improved Seismic Performance

1993 ◽  
Vol 9 (3) ◽  
pp. 319-334 ◽  
Author(s):  
Robert D. Hanson
Keyword(s):  
Energy Dissipation ◽  
Earthquake Response ◽  
Code Design ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Single Degree Of Freedom ◽  
Equivalent Damping ◽  
Supplemental Damping ◽  
Stiffness Characteristics ◽  
Energy Dissipation Devices

The results of several studies on the effects of supplemental viscous damping on the response of elastic and elasto-plastic single-degree-of-freedom systems are used to provide insight to the effects of large damping on the earthquake response of buildings and the interpretation of studies reporting the equivalent damping and increased stiffness characteristics of specific types of supplemental energy dissipation devices. Extension to multi-story buildings is discussed briefly. Conversion of the properties of viscous, viscoelastic, friction, and metallic yield device characteristics to equivalent viscous damping are proposed. Specific recommendations for the incorporation of the effects of supplemental energy dissipation devices in the code design process are given.

Damping characteristics of a magneto-rheological damper with dual independent controllable ducts

2021 ◽  
pp. 1045389X2110188
Author(s):  
Jianqiang Yu ◽  
Xiaomin Dong ◽  
Tao Wang ◽  
Zhengmu Zhou ◽  
Yaqin Zhou
Keyword(s):  
Dynamic Range ◽  
Fluid Flows ◽  
Mr Damper ◽  
Viscous Damping ◽  
The Novel ◽  
The Finite Element Method ◽  
Damping Force ◽  
Damping Characteristics ◽  
Magneto Rheological ◽  
The Mathematical Model

This paper presents the damping characteristics of a linear magneto-rheological (MR) damper with dual controllable ducts based on numerical and experimental analysis. The novel MR damper consisting of a dual-rod cylinder system and a MR valve is used to reduce the influences of viscous damping force and improve dynamic range. Driven by the dual-rod cylinder system, MR fluid flows in the MR valve. The pressure drop of the MR valve with dual independent controllable ducts can be controlled by tuning the current of two independent coils. Based on the mathematical model and the finite element method, the damping characteristics of the MR damper is simulated. A prototype is designed and tested on MTS machine to evaluate its damping characteristics. The results show that the working states and damping force of the MR damper can be controlled by the two independent coils.

scholarly journals Stochastic P-bifurcation in a bistable Van der Pol oscillator with fractional time-delay feedback under Gaussian white noise excitation

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Yajie Li ◽  
Zhiqiang Wu ◽  
Guoqi Zhang ◽  
Feng Wang ◽  
Yuancen Wang
Keyword(s):  
Time Delay ◽  
White Noise ◽  
Gaussian White Noise ◽  
Singularity Theory ◽  
Van Der Pol Oscillator ◽  
Order System ◽  
Damping Force ◽  
Van Der Pol ◽  
Restoring Force ◽  
White Noise Excitation

Abstract The stochastic P-bifurcation behavior of a bistable Van der Pol system with fractional time-delay feedback under Gaussian white noise excitation is studied. Firstly, based on the minimal mean square error principle, the fractional derivative term is found to be equivalent to the linear combination of damping force and restoring force, and the original system is further simplified to an equivalent integer order system. Secondly, the stationary Probability Density Function (PDF) of system amplitude is obtained by stochastic averaging, and the critical parametric conditions for stochastic P-bifurcation of system amplitude are determined according to the singularity theory. Finally, the types of stationary PDF curves of system amplitude are qualitatively analyzed by choosing the corresponding parameters in each area divided by the transition set curves. The consistency between the analytical solutions and Monte Carlo simulation results verifies the theoretical analysis in this paper.

High Efficient Viscoelastic Damper for Heavy Trucks

2012 ◽  
Vol 215-216 ◽  
pp. 318-321 ◽  
Author(s):  
Sai Fei Zhang ◽  
Xiao Ling Liu ◽  
Yong Liu
Keyword(s):  
Flow Rate ◽  
Viscous Damping ◽  
Calculation Formula ◽  
Performance Curve ◽  
Test Results ◽  
Viscoelastic Damper ◽  
Damping Force ◽  
Heavy Trucks ◽  
High Efficient ◽  
Damper Design

In this paper, a new viscoelastic damper design for heavy trucks is presented and a calculation formula of viscous damping force considering the effect of Viscoelastic Fluids (VF) flow rate is carried out. By numerically simulating this equation, curves of the viscoelastic damper performance curve is obtained, and the results show that theoretical calculation result and the test results are well consistent, with the exception at the start point. Theoretical curves are more plumpness in compared with test curves.

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