Aggregator command to add the Shear force-deformation

[gooddaytogo]

Hi, everybody,
I am using the section Aggregator command to add the Shear force-deformation to the existing fiber section, but I am confused about how to define the Shear force-deformation relation for the uniaxialMaterial, anybody can help or provide some reference about it? Thanks a lot.

[mhscott]

Use a uniaxialMaterial to define the section shear force-shear deformation relationship, then add it to the fiber section using 'Vy' in the aggregator. I don't have a specific example on hand, but you can search the message board as this is not an uncommon question.

[selimgunay]

If you are using an elastic response

uniaxialMaterial Elastic $matTag $GA

If inelastic (using Steel01 for example to represent bilinear relationship)

uniaxialMaterial Steel01 $matTag $Fy $GA $b

Fy is the shear capacity, GA is the multiplication of shear modulus and shear area, b is the ratio of slope after yield to GA. You can have it negative to represent brittle failure

[mhscott]

Thanks, Selim!

[gooddaytogo]

Use a uniaxialMaterial to define the section shear force-shear deformation relationship, then add it to the fiber section using 'Vy' in the aggregator. I don't have a specific example on hand, but you can search the message board as this is not an uncommon question.

Thanks, it is very helpful,

[gooddaytogo]

If you are using an elastic response

uniaxialMaterial Elastic $matTag $GA

If inelastic (using Steel01 for example to represent bilinear relationship)

uniaxialMaterial Steel01 $matTag $Fy $GA $b

Fy is the shear capacity, GA is the multiplication of shear modulus and shear area, b is the ratio of slope after yield to GA. You can have it negative to represent brittle failure

Thanks for your reply.
Can I understand it in this way, when using uniaxialMaterial command:
For shear, we use GA to describe the relation between F and gamma;
For torsion, we use GJ to describe the relation between T and theta;

As for Fy, does it mean the shear force when the section starts to yields?
Hope you can help me confirm it.

Another is for the A in GA, do we need to use the whole area or the effective area and why? Thanks.

[mhscott]

Yes, the "Fy" is interpreted as yield shear force.

You can use whatever "A" you want in GA ... it's just a number to the material model

[selimgunay]

Fy is the shear capacity and in a bilinear model that you use, it corresponds to the yield force.

A is shear area which is equal to 5/6 of the total area for rectangular sections and 9/10 of the total area for circular sections

[gooddaytogo]

Fy is the shear capacity and in a bilinear model that you use, it corresponds to the yield force.

A is shear area which is equal to 5/6 of the total area for rectangular sections and 9/10 of the total area for circular sections

Brilliant, for the shear area, I am trying to find some references where you can derive the shape factor for any shape, would you have any resources for it? Thanks.

[selimgunay]

You can find a derivation and some references here:

http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf

[gooddaytogo]

You can find a derivation and some references here:

http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf

Awesome, many thanks.