Hysteretic
This command is used to construct a uniaxial bilinear hysteretic material object with pinching of force and deformation, damage due to ductility and energy, and degraded unloading stiffness based on ductility.
uniaxialMaterial Hysteretic $matTag $s1p $e1p $s2p $e2p
<$s3p $e3p> $s1n $e1n $s2n $e2n <$s3n $e3n> $pinchX $pinchY
$damage1 $damage2 <$beta>
matTag
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integer tag identifying material |
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stress and strain (or force & deformation) at first point of the envelope in the positive direction |
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stress and strain (or force & deformation) at second point of the envelope in the positive direction |
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stress and strain (or force & deformation) at third point of the envelope in the positive direction (optional) |
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stress and strain (or force & deformation) at first point of the envelope in the negative direction |
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stress and strain (or force & deformation) at second point of the envelope in the negative direction |
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stress and strain (or force & deformation) at third point of the envelope in the negative direction (optional) |
pinchx
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pinching factor for strain (or deformation) during reloading |
pinchy
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pinching factor for stress (or force) during reloading |
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damage due to ductility: D1(mu-1) |
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damage due to energy: D2(Eii/Eult) |
beta
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power used to determine the degraded unloading stiffness based on ductility, mu-beta (optional, default=0.0) |


NOTE:
- In cases $s3p > \(s2p and abs(\)s3n) > abs($s2n), the envelope of the hysteretic material after $e3p or $e3n follows the slope defined by 2nd and 3rd point of the envelope.
- In cases $s3p <= \(s2p and abs(\)s3n) <= abs($s2n) the envelope of the hysteretic material after $e3p or $e3n is a flat line with a constant stress (or force) equal to $s3p or $s3n.
Examples
Effects of Hysteretic-Material Parameters 1
Code Developed by: Michael Scott (Oregon State University) & Filip Filippou (UC Berkeley)
Images Developed by: Silvia Mazzoni