Alternative to SLIDER MPC* for enforcing planar sections 1

[bfillery]

Hi all

I was wondering if somebody could suggest an alternative way of enforcing a planar section requirement as described by the SLIDER MPC* (i.e. enforces a line to remain plane but allows the line to change length) by using either coupling or constraint equations in ABAQUS CAE so that Python scripting, rather than a full batch input may be utilised.

Thanks

Brent

 

[brep]

If you mean you want a plane to remain plane...

1. Create a reference point on the plane
2. Create a local csys with original that ref pnt and with a direction (e.g. direction 1) normal to the plane
3. Create a kinematic coupling with the ref pnt as the control point and the planar face as the surface. Constrain only the U1 direction.

All of this can be done easily in ABAQUS/CAE, and if you want to create a macro/plugin to automate the 3 steps, then that's pretty simple too.

 

[brep]

Sorry, step 2 should read: (stupid autocorrect - I was typing this in Outlook)


2. Create a local csys with origin at that ref pnt and with a direction (e.g. direction 1) normal to the plane

 

[bfillery]

Thanks for that brep

I have little experience with local csys' and therefore have the following questions.

1. By placing the local csys origin at the referece point, is the local csys effectively coupled to the motion of the reference point.

2. I am guessing it is important to define the local csys such that the 1 direction (as mentioned above) is always normal to the plane to be constrained, even during subsequent deformations (i.e. translations and rotations of the plane). How is the local csys defined to ensure this condition is met?

Thanks

Brent

 

[gurmeet2003]

bfillery,

The local co-ordinate system is just what it says. It has it's own origin and co-ordinate directions. It is not coupled to anything else.

If you are using Abaqus CAE, to create a local co-ordinate system go to tools>datum> co-ordinate system. There are a number of options to create a local co-ordinate system and you can pick the one that suits you.

Gurmeet