Maxwell Material: Difference between revisions

From OpenSeesWiki
Jump to navigation Jump to search
No edit summary
No edit summary
Line 40: Line 40:
|The sensitivity of the viscous damper with respect to its axial stiffness is shown in Figures 2 to 5 for the following set of parameters:   
|The sensitivity of the viscous damper with respect to its axial stiffness is shown in Figures 2 to 5 for the following set of parameters:   
|-
|-
| [[File:Fig1.png|300px|thumb|left|Figure 1. Viscous Damper with K=300.0 kN/mm, Cd=73.0kN(s/mm)<sup>0.6</sup>, a=0.60]] , [[File:Fig2.png|300px|thumb|right|Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=12.0kN(s/mm)<sup>1.0</sup>, a=1.0]]  
| [[File:Fig1.png|425px|thumb|left|Figure 1. Viscous Damper with K=300.0 kN/mm, Cd=73.0kN(s/mm)<sup>0.6</sup>, a=0.60]] [[File:Fig2.png|425px|thumb|right|Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=12.0kN(s/mm)<sup>1.0</sup>, a=1.0]]  
|-
|-
| [[File:Fig1.png|425px|thumb|left|Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=683.0kN(s/mm)<sup>0.1</sup>, a=0.1]] , [[File:Fig2.png|425px|thumb|right|Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=1017.7kN(s/mm)<sup>0.01</sup>, a=0.01]]  
| [[File:Fig1.png|425px|thumb|left|Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=683.0kN(s/mm)<sup>0.1</sup>, a=0.1]] [[File:Fig2.png|425px|thumb|right|Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=1017.7kN(s/mm)<sup>0.01</sup>, a=0.01]]  
|-
|-
|-
|-

Revision as of 18:14, 21 August 2013



This command is used to construct a ViscousDamper material, which represents the Maxwell Model (linear spring and nonlinear dashpot in series). The Maxwell material simulates the hysteretic response of viscous dampers.

uniaxialMaterial ViscousDamper $matTag $K $Cd $alpha
$matTag integer tag identifying material
$K Elastic stiffness of linear spring (to model the axial flexibility of a viscous damper (brace and damper portion)
$Cd Viscous parameter of damper
$alpha Viscous damper exponent

Examples:

1. Input parameters:
Assume a viscous damper with axial stiffness K=300.0kN/mm, viscous parameter Cd=280.3kN(s/mm)0.3, and exponent a=0.30.
The input parameters for the material should be as follows:
uniaxialMaterial ViscousDamper 1 300 280.3 0.30
Using these properties, Figure 1 shows the hysteretic response of this damper for sinusoidal displacement increments of 12, 24 and 36mm and a frequency f = 0.5Hz.
The sensitivity of the viscous damper with respect to its axial stiffness is shown in Figures 2 to 5 for the following set of parameters:
Figure 1. Viscous Damper with K=300.0 kN/mm, Cd=73.0kN(s/mm)0.6, a=0.60
Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=12.0kN(s/mm)1.0, a=1.0
Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=683.0kN(s/mm)0.1, a=0.1
Figure 2. Viscous Damper with K=300.0 kN/mm, Cd=1017.7kN(s/mm)0.01, a=0.01
2. Tcl input file for Viscous Damper Calibration.
3. OpenSees Example of 1-story steel moment frame with a viscous damper: (to be posted)

References:

[1] Olsson, A.K., and Austrell, P-E., (2001), "A fitting procedure for viscoelastic-elastoplastic material models," Proceedings of the Second European Conference on Constitutive Models for Rubber, Germany, 2001.
[2] Ottosen, N.S., and Ristinmaa, M., (1999). "The mechanics of constitutive modelling, (Numerical and thermodynamical topics)," Lund University,Division of Solid Mechanics, Sweden, 1999.

Code Developed by : Prof. Kazuhiko Kasai (Tokyo Institute of Technology) and implemented by Sarven Akcelyan & Prof. Dimitrios G. Lignos, (McGill University)

Retrieved from "https://opensees.ist.berkeley.edu/wiki/index.php?title=Maxwell_Material&oldid=10765"