Modelling Sealing rubber with Connector type Cartesian-Cardan

[nabilishes]

Hi everyone,

I am modelling a rubber sealing with Abaqus Connector type Cartesian-Cardan. I have local coordinate system applied to the *CONNECTOR SECTION. The coordinate system is however pointing from direction Node B to Node A (see attached picture). I am using ANSA as pre-processor and the direction of local coordinate system for the connector has been set automatically when creating the connector.

I am applying a non-linear Force vs displacement compression stiffness to the x-component of the connector elasticity as its connector behaviour. My data has positive displacement in compression direction (see image).
My question is
1. From my understanding, the forces acting on the connector is based on the relative movement of the connector nodes. By default, if B is moving towards A, it should be negative displacement and is in compression. However, in my case, i have a local coordinate system defined on the connector section. So if B moves towards A, the relative movement is considered as positive which also mean the forces magnitude should be also positive in this direction (compression). Is my understanding correct, as this will affect the direction of the force and displacement in the *CONNECTOR ELASTICITY table?

Thank you

 

[FEA way]

Connectors use so called CORM (components of relative motion) - translations and rotations relative to local CSYS. With rotations it’s not always simple as they aren’t always defined about orthogonal directions (depends on the type of connector). However, translations are simply defined in local directions. So the second node’s displacement is identified by coordinates relative to local directions at the first node.

 

[nabilishes]

So the forces defined in the force vs displacement *CONNECTOR ELASTICITY table also follows the coordinates relative to local directions at the first node?

 

[FEA way]

Yes, forces are also defined with respect to aforementioned components of relative motion.

 

[nabilishes]

Thanks for the clarification