about the use of hysteretic material~~~

[borjiajia]

Now I want to simulate a simply supported beam with reversed load. I have uesd steel02 and concrete02, but the result don't have pinching effect as the experiment. So I want to use the hysteretic material instead of steel02, do you think it makes sense?

If yes, the problem is that I cannot find how to define the parameters in the hyseretic material. Are they defined by experiment? Is there any references for me to read? Thank you.

##----uniaxialMaterial Hysteretic $matTag $s1p $e1p $s2p $e2p <$s3p $e3p> $s1n $e1n $s2n $e2n <$s3n $e3n> $pinchX $pinchY $damage1 $damage2 <$beta>-----

[vesna]

If you have a fiber section it is not realistic to assign stress-strain relationship with pinching to your longitudinal bars, since the pinching happens due to progressive increase of tension strain in transverse reinforcement under cyclic loading. This leads to lateral dilatation of the member cross-section with the widening cracks and eventual breakdown of the integrity of the concrete core.

In the old OpenSees manual (http://opensees.berkeley.edu/OpenSees/m ... sermanual/) you can find how pinch and damage parameters affect the hysteresis curve of Hysteretic material. In general, these parameters are calibrated based on experimental results.

[borjiajia]

1,You mean a model with fiber section is not suitable with hysteretic material?
2,Then If I want to simulate the pinching effect with hyseretic material, what section should be used instead of fiber section?

[vesna]

1. what I meant is that it is not realistic to assign hysteretic material with pinching to longitudinal steel bars.
2. if you want to use hysteretic material then you can either use uniaxial section when with this material you define moment-curvature relationship or you can use this material to define zero-length elements at the location of concentrated plasticity.