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Paper Information

Journal:   MODARES CIVIL ENGINEERING JOURNAL   APRIL 2017 , Volume 17 , Number 1 ; Page(s) 243 To 252.
 
Paper: 

CONSTITUTIVE MODEL FOR CONTRACTIBLE VISCOUS DASHPOTS

 
 
Author(s):  MOUSAVI SH.*, ZIAEIFAR M.*
 
* STRUCTURAL RESEARCH CENTER, INTERNATIONAL INSTITUTE OF EARTHQUAKE ENGINEERING AND SEISMOLOGY (IIEES)
 
Abstract: 

New techniques in seismic design of structural systems are based on flexibility and energy dissipation approach. In this approach, the role of energy dissipaters is quite important. The behaviors of these devices and the way they dissipate energy have always been a concern for many researchers to improve the efficiency of these important parts of the structural systems. There has been a large number of investigations on behavioral aspects of energy dissipating devices capable of using in seismic design of structural systems.
The concept of adding dissipating supplemental devices to a structure assumes that much of the energy imposed to the structure from a transient will be absorbed, not by the structure itself, but rather by supplemental damping elements. Among them, viscous devices have received considerable attention. The behavior of these energy dissipaters are dependent, not only on the relative velocity, but also on a large number of other parameters including relative displacement, compressibility of fluid, internal friction etc.
The behavior of viscous devices are also dependent on the frequency of excitation and their thermal conditions. Determination of mechanical characteristics of these devices is usually based on experimental studies including cyclic tests in different amplitudes and frequencies.
In this study, a new type of viscous dashpot in which the main body of the device has been made of contractible steel bellows (developed in IIEES) is chosen for experimental studies. The viscous device has the capacity of 500 kN and axial deformability of
±150mm. The tests have been carried out using an actuator capable of providing axial forces up to 300 kN in cyclic tests with displacement range of ±120mm. Axial forces on dashpot and resulted deformations on the device during experiments have been used to find the relationships between applied forces and induced relative displacement and velocity on the device.
According to the results, the dashpot shows a dominant viscous behavior. It also represents a small frictional behavior in order of 10 kN (on average). The device also shows a frictional feature that is proportional to its internal fluid pressure. This feature is due to a small asymmetry in manufacturing some parts of the device, but it can be used later to improve the behavior of contractible dashpots. To be able to develop a model for this device, the test results are used in the form of cyclic behavior and time series. The time series results show the fact that there is not a linear proportionality between forces and velocity experienced by the dashpot in all the range of excitation frequencies. In addition, according to the test results, damping constants for this device is also dependent on the excitation frequency. Different types of behavioral models have been examined for the device. The proper model is proposed based on the three element type Maxwell model. The model can be further improved to represent the pressure dependent frictional forces in this dashpot.

 
Keyword(s): ENERGY DISSIPATERS, EXPERIMENTAL STUDIES, CONTRACTIBLE DASHPOTS, FRICTIONAL BEHAVIOR, VISCOUS BEHAVIOR
 
 
References: 
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Click to Cite.
APA: Copy

MOUSAVI, S., & ZIAEIFAR, M. (2017). CONSTITUTIVE MODEL FOR CONTRACTIBLE VISCOUS DASHPOTS. MODARES CIVIL ENGINEERING JOURNAL, 17(1 ), 243-252. https://www.sid.ir/en/journal/ViewPaper.aspx?id=570303



Vancouver: Copy

MOUSAVI SH., ZIAEIFAR M.. CONSTITUTIVE MODEL FOR CONTRACTIBLE VISCOUS DASHPOTS. MODARES CIVIL ENGINEERING JOURNAL. 2017 [cited 2021May12];17(1 ):243-252. Available from: https://www.sid.ir/en/journal/ViewPaper.aspx?id=570303



IEEE: Copy

MOUSAVI, S., ZIAEIFAR, M., 2017. CONSTITUTIVE MODEL FOR CONTRACTIBLE VISCOUS DASHPOTS. MODARES CIVIL ENGINEERING JOURNAL, [online] 17(1 ), pp.243-252. Available: https://www.sid.ir/en/journal/ViewPaper.aspx?id=570303.



 
 
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