Simplified seismic code design procedure for friction-damped steel frames

1999 ◽  
Vol 26 (1) ◽  
pp. 55-71 ◽  
Author(s):  
Yaomin Fu ◽  
Sheldon Cherry
Keyword(s):  
Design Procedure ◽  
Steel Structures ◽  
Lateral Force ◽  
Building Codes ◽  
Degree Of Freedom ◽  
Friction Damper ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Damped System ◽  
Seismic Force

This paper describes the development of a proposed seismic design procedure for friction-damped steel structures, which employs the lateral force provisions used in many modern building codes. Closed-form expressions are first derived that relate the normalized response of a single degree of freedom friction-damped system with the system parameters, such as bracing stiffness ratio, damper slip ratio, and frame member ductility. A parametric analysis is then used to reveal that the seismic displacement of a friction-damped frame can be controlled by combining the frame stiffness with the bracing stiffness of the friction damper component, while the seismic force can be controlled by the damper slip force. A force modification factor (equivalent to the code R-factor) and displacement estimate for a friction-damped system are next determined. The single degree of freedom results are subsequently used to develop expressions for dealing with the multi degree of freedom situation, which permits the seismic lateral force design procedure adopted by many current building codes to be applied to friction-damped systems. The proposed procedure allows the frame response to be controlled so that the displacement can be limited to small magnitudes and the overall structural shape to an essentially straight-line deformation. Design examples illustrate that friction-damped frame systems are economical and offer a better overall response performance than that provided by conventional systems under the design earthquake.Key words: passive energy dissipation system, friction damper, steel frame, design procedure, static analysis.

scholarly journals Dynamic Response of Breasting Dolphin Moored with 40,000 DWT Ship due to Parallel Passing Ship Phenomenon

2018 ◽  
Vol 147 ◽  
pp. 05003
Author(s):  
Heri Setiawan ◽  
Muslim Muin
Keyword(s):  
Differential Equation ◽  
Ordinary Differential Equation ◽  
Dynamic Response ◽  
Computer Program ◽  
Lateral Force ◽  
Degree Of Freedom ◽  
Hydrodynamic Interactions ◽  
Single Degree Of Freedom ◽  
Sdof System ◽  
Single Degree

When a ship is moving through another ship moored nearby, hydrodynamic interactions between these ships result in movements of the moored vessel. The movement may occur as surge, sway, and/or yaw. When a ship is passing a moored vessel parallelly, this effect will give a dominant lateral force on the moored ship and response from this phenomenon will appear in a certain time. Only dynamic response due to sway force is considered in this study, the sway force shall be absorb by the breasting dolphin. 40,000 DWT shall be moored to the breasting dolphin. Three passing ships size are considered, the breasting dolphin shall be modeled as a single degree of freedom model. This model will be subjected to a force caused by parallel passing ship. The model is assumed to be in a state of quiet water, this assumption is taken so that the fluid does not provide additional force on the model. The SDOF system shall be analyzed using a computer program designed to solve an ordinary differential equation.

Single Degree of Freedom Forced Vibration System

2021 ◽  
pp. 41-79
Keyword(s):  
Forced Vibration ◽  
Influence Factor ◽  
Initial Conditions ◽  
Degree Of Freedom ◽  
Transient Solution ◽  
Vibration System ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Damped System ◽  
Arbitrary Loading

This chapter concerns the study of forced vibration of a single degree of freedom system, treating undamped and damped system under harmonic, periodic, and arbitrary loading with different cases and examples. Passing by all components of the general solution of an undamped forced system, which are a transient solution, depends only on initial conditions, transient solution due to the load at the end the stationary solution. In this chapter, a study of the dynamic influence factor depends on the ration between load frequency and structure one is presented.

On the Use of Clearance in Viscous Dampers to Limit High Frequency Force Transmission

1961 ◽  
Vol 83 (1) ◽  
pp. 50-52 ◽  
Author(s):  
M. E. Gurtin
Keyword(s):  
Steady State ◽  
High Frequency ◽  
Degree Of Freedom ◽  
Viscous Damper ◽  
Force Transmission ◽  
Viscous Dampers ◽  
Single Degree Of Freedom ◽  
High Frequencies ◽  
Single Degree ◽  
Damped System

The steady-state vibration of a single degree of freedom system with clearance in the viscous damper is investigated. The results show that the clearance damper combines the low resonant force transmission feature of the viscous damped system and the characteristic of low force transmission at high frequencies of the undamped system.

scholarly journals Analysis of Single-degree-of-freedom Systems Containing Multi-functional Friction Damper

2014 ◽  
Vol 79 ◽  
pp. 500-505
Author(s):  
Chia-Shang Chang Chien ◽  
Lyan-Ywan Lu ◽  
Yu-Lin Tsai
Keyword(s):  
Degree Of Freedom ◽  
Friction Damper ◽  
Single Degree Of Freedom ◽  
Single Degree

Analysis of Beam-Like Structures With Displacement-Dependent Friction Forces: Part II — Multi-Degree-of-Freedom Model

1995 ◽  
Author(s):  
Wayne E. Whiteman ◽  
Aldo A. Ferri
Keyword(s):  
Dry Friction ◽  
Time Integration ◽  
Degree Of Freedom ◽  
Mode Analysis ◽  
Friction Damper ◽  
Compressor Blades ◽  
Friction Forces ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Damping Characteristics

Abstract A multi-mode analysis of a beam-like structure undergoing transverse vibration and subjected to a displacement-dependent friction force is conducted. The level of displacement-dependence is governed by a ramp angle and spring arrangement as discussed in Part I. The system is studied by using harmonic balance as an approximate analytical solution and then by using a time integration method. The damping characteristics of the system are studied in detail. The results qualitatively agree with those obtained using a single-degree-of-freedom analysis of this system reported in Part I. Interesting findings include the appearance of internal resonance peaks when multiple modes are considered. Also, as with the earlier single-degree-of-freedom study, two dynamic response solutions exist at certain parameter values. It is found that the ability to control the amplitude of the response is a function of the frequency range considered. In general, near modal resonance peaks, the amplitude of the response decreases with increasing ramp angle. However, in an “overlapping” region between resonance peaks, the amplitude of the response actually increases with increasing ramp angle. Detailed analysis of the damping characteristics indicate that the dry friction damper is most effective in damping the fundamental mode. The other critical observation is that the damping contribution from the displacement-dependent dry friction damper is “viscous-like” in nature and relatively insensitive to the amplitude of the response. This result suggests that in the case of turbine or compressor blades, this type of damping arrangement may be effective in the suppression of flutter.

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