About zerolength element

[drowning6]

I set three zerolength elements in orthogonal directions by the command below.

element zeroLength 951 1 1111 -mat 20 20 1 -dir 1 2 3;
or
element zeroLength 951 1 1111 -mat 20 -dir 1 ;
element zeroLength 951 1 1111 -mat 20 -dir 2 ;
element zeroLength 951 1 1111 -mat 1 -dir 3;

1. But they do not work toghether in either way.
I mean it seams each zerolength element only work lonely assuming the other two direction is fixed.
Is this the setting of the zerolength element?

2. Can I consider the coupled effects of these three zerolength element?

Thanks for all.

Regards.

[mhscott]

1. They work in orthogonal directions without coupling

2. element CoupledZeroLength tag ndI ndJ 1 2 20 would, for example, couple material 20 between dirs 1 and 2 ... it computes deformation magnitude from dirs 1 and 2 and resolves resulting force along dirs 1 and 2

[drowning6]

Thank you so much, Dr. Scott.

This command is for 2d element.
For example, if I plan to couple x,y,z direction together. So I should couple x,y and y,z and x,z seperately, is this correct?