Question about zeroLength curvature

[BLJ]

Hello, I have a question about zeroLength element. I know that the curvature is the inverse radius of a beam section. But what the curvature is for zeroLength element. If I define the moment-curvature property of a zeroLength element, is the curvature here the relative rotation between two nodes of the zeroLength element? Then how to define it? thank you.

[fmk]

the zeroLength element takes a material which provides the force-deformation relationship .. there is no moment-curvature relationship provided, as you point out it has no length.

[songlianglong]

[quote="fmk"]the zeroLength element takes a material which provides the force-deformation relationship .. there is no moment-curvature relationship provided, as you point out it has no length.[/quote]
the force here refer to what?

[fmk]

when a uniaxial material is used in a zeroLength element, the material provides the relationship between global forces at the two nodes and the displacement at the nodes.

when used in a fiber-section, the material provides the stress-strain relationship for a fiber at a point in the section.

[songlianglong]

[quote="fmk"]when a uniaxial material is used in a zeroLength element, the material provides the relationship between global forces at the two nodes and the displacement at the nodes.

when used in a fiber-section, the material provides the stress-strain relationship for a fiber at a point in the section.[/quote]
how can i get the moment-theta relationship in the section where the zerolengthsection element is defined?what is different when i get the moment-theta relationship in a sectioon of another element (such as a elastic element etc. ) is defined?