CastFuse
This command is used to construct a CastFuse uniaxial material. The CastFuse material simulates the hysteretic response a cast yielding fuse (CSF) for concentrically braced frames. The details of a CSF-brace are discussed in Gray et al. [1,2]. Isotropic hardening is modeled with the rules developed by Filippou et al. [3].
uniaxialMaterial Cast $matTag $n $bo $h $fy $E $L $b $Ro
$cR1 $cR2 <$a1 $a2 $a3 $a4>
matTag
|
integer tag identifying material |
n
|
Number of yield fingers of the CSF-brace |
bo
|
Width of an individual yielding finger at its base of the CSF-brace |
h
|
Thickness of an individual yielding finger |
fy
|
Yield strength of the steel material of the yielding finger |
E
|
Modulus of elasticity of the steel material of the yielding finger |
L
|
Height of an individual yielding finger |
b
|
Strain hardening ratio |
Ro
|
Parameter that controls the Bauschinger effect. Recommended Values for $Ro=between 10 to 30 |
|
Parameter that controls the Bauschinger effect. Recommended Value $cR1=0.925 |
|
Parameter that controls the Bauschinger effect. Recommended Value $cR2=0.150 |
|
isotropic hardening parameter, increase of compression yield envelope as proportion of yield strength after a plastic deformation of $a2*(P<sub>p</sub>/K<sub>p</sub>) |
|
isotropic hardening parameter (see explanation under $a1). (optional default = 1.0) |
|
isotropic hardening parameter, increase of tension yield envelope as proportion of yield strength after a plastic deformation of $a4*(P<sub>p</sub>/K<sub>p</sub>) |
|
isotropic hardening parameter (see explanation under $a3). (optional default = 1.0) |
Gray et al. [1] showed that the monotonic backbone curve of a CSF-brace with known properties (n, b<sub>o</sub>, h, L, fy, E) after yielding can be expressed as a close-form solution that is given by, |
P = P<sub>p</sub>/cos(2d/L), in which d is the axial deformation of the brace at increment i and P<sub>p</sub> is the yield strength of the CSF-brace and is given by the following expression |
P<sub>p</sub> = nb<sub>o</sub>h<sup>2</sup>f<sub>y</sub>/4L |
The elastic stiffness of the CSF-brace is given by, |
K<sub>p</sub> = nb<sub>o</sub>Eh<sup>3</sup>f<sub>y</sub>/6L<sup>3</sup> |
Examples:
References:
[1] |
Gray, M.G., Christopoulos, C., Packer, J.A., (2010). “Cast Steel Yielding Fuse for Concentrically Braced Frames,” Proceedings of the 9th U.S. National and 10th Canadian Conference on Earthquake Engineering, July 25-29, 2010, Toronto, Ontario, Canada, paper No. 595. |
[2] |
Gray, M.G., Christopoulos, C., Packer, J.A., Lignos, D.G. (2012). “Development, Validation and Modeling of the New Cast Steel Yielding Brace System,” Proceedings ASCE Structures Congress, March 29th-31st, Chicago, IL, USA, SEI institute. |
[3] |
Filippou, F. C., Popov, E. P., Bertero, V. V. (1983). “Effects of Bond Deterioration on Hysteretic Behavior of Reinforced Concrete Joints,” Report EERC 83-19, Earthquake Engineering Research Center, University of California, Berkeley. |
Code Developed by : by Dr. Dimitrios G. Lignos, (McGill University)